First Ride: ARC8 Evolve FS - The Future of XC Race Bikes?

May 27, 2022 at 13:03
by Dan Roberts  



In recent times we've seen the infiltration of more aggressive geometry into bikes with shorter and shorter travel. The current crop of trail bikes is as capable as ever. But what happens when you take some of that geometry recipe and sprinkle it on something with even less travel?

XC bikes have been getting a bit more aggressive in recent years as a response to the tougher tracks. But perhaps not quick enough for the Swiss brand ARC8. In the same way that Mike Levy used his crystal ball to predict the geometry of the future with the Grim Donut, ARC8 looked into their, arguably clearer, crystal ball to see what XC bikes of the future could look like
Evolve FS Details
• 29" wheels
• Carbon fiber front & rear triangles
• Slider suspension
• 100mm - 110mm rear travel
• 100mm - 120mm front travel
• M and L sizes
• 1775g frame weight (actual, size L, with shock)
• Bike Pricing: €5,999 to €9,999
• Frame Pricing: €3,299
arc8bicycles.com

What they saw was not only truly aggressive geometry for an XC bike, but some innovative solutions to suspension, manufacture and bike segmentation. The result is the Evolve FS.




ARC8's first bike - the Essential. Intended as an aggressive trail bike at the time, it also saw its fair share of XC racing thanks to its lightweight and efficient character.

Some History

The bike that started ARC8, the Essential, was done back in 2016, long before the public ever laid eyes on it. It was designed to be an aggressive trail bike for the time, and while it delivered on that it also turned out to be quite an efficient and light package that saw quite some action in XC racing.

Since then, XC has been evolving (no pun intended). Scott’s latest iteration of the Spark boasts 120mm of travel in a field of race bikes that still cling to 100mm. Wider tires and dropper posts are bringing the bikes closer to the average person’s mountain bike, ridden weekend after weekend all over the hills and forests.

At the same time that XC was embracing, well, less XC things, certain media people were also coining phrases and inadvertently defining new categories of bike. While the downcountry tag may be new, these bikes have been existing for much longer. Taking an XC bike and making it more capable on the downs isn’t anything new. When I worked for Scott I did the same with a previous generation Spark and loved the results. Jonas, founder of ARC8, enjoyed this too, riding a beefed up BMC XC bike for years before down country was ever a market segment.

Jonas, one of the main men behind ARC8, was riding downcountry long before it became a defined segment. His BMC got wider bars, meatier tires, a dropper and a bit more travel up front. This aggro XC bike concept has been something brewing in the minds of ARC8 for quite some time.

All these thoughts of XC progression and downcountry were whirling round the minds at ARC8 prior to starting the development of the Evolve. One more was the slow, but consistent, infiltration of aggressive geometry into shorter travel bikes. Perhaps this is where ARC8 used its relatively small size to its advantage. Instead of slackening the head angle just a touch, or adding a couple of mms to the reach, they went all in.

They decided on a geometry that really stands out in this travel bracket but is something they believe might be the resting point for XC bikes in the future, going even further to say that they believe there will be no border between the two categories. Their thought, and maybe hope, is that bikes like the Evolve will be the XC race bikes of the future.

I rode a lot of XC during my tenure at Scott, even dabbling in a few XC races here and there. The infamous Lunchtime World Cup was nothing short of a battle each day that could rival the live stream of any race weekend. And if the ARC8 Evolve represents the future of XC racing, then boy are we in for a treat.





Surface are was reduced by 11% in the front triangle, compared to the Essential, without impacting the stiffness and strength of the overall frame.
But the rear triangle saw a drop in surface area of 22%, which was one of the biggest factors in saving weight. But it certainly wasn't the only one.

Frame Development & Details

Weight is still the priority of XC race bikes. Well, I thought it was but then we started to stuff everything inside the frame and now I’m not so sure anymore.

Either way, ARC8 put it pretty high up their list and used all the tools in their toolbox to shed as much weight as possible. The original Essential wasn’t designed as an XC bike but ended up being competitively light while having a very low number of warranty cases. So ARC8 used it as a starting point. And with very few warranty cases over the years, there was big confidence in their production partner to push the limits of lightweight manufacturing.

Reducing the surface area of a frame is a good way to drop the weight. It has to go hand in hand with balancing stiffness, strength, design and manufacturability, but reducing the surface area by 11% in the front triangle and 22% in the rear triangle compared to the Essential gave an expected weight reduction of 253g in carbon material and paint alone.

You can also drop the weight by using a thinner walled structure or using a less dense material, but there’s not much available at the moment that’s less dense than carbon fibre composite, while still being suitable to a mountain bike's manufacture and use. And paper-thin walls on a mountain bike are definitely not a good idea.

Simplifying the design of the Essential opened the door to shedding even more weight. Eliminating as much pivot hardware as possible is a low hanging fruit that ARC8 grabbed with both hands. The ten bearings on the Essential was dropped to just two 61902s on the Evolve. And combined with the slider being such a compact little item, all told the drop in hardware came to 118g over the Essential.

The Evolve FS uses the flat mount standard to mount the brake, which allowed ARC8 to simplify the composite structure, saving weight and making the frame have a higher repeatable quality.
The same idea was used at the main pivot. The mainframe is moulded complete with the window for the chainstay machined afterwards. It also simplifies the manufacturing of the chainstays, further saving weight.

With the weight falling off faster than early freeriders on skinnie, ARC8 tried not to lose sight of making something that is easy to manufacture. Designing the bike to be made from carbon fibre composite from the beginning, along with knowing their production partner inside and out meant that ARC8 could take further advantage of using the internal pressure created by the bag or bladder inside of the frame to compact the composite evenly and cleanly during moulding. This gave them a frame with less complexity, less potential for manufacturing errors and less material needed to suit the process of moulding using external pressure from the mould or mould inserts.

The main pivot area is a good example - moulded as a closed structure from only internal pressure with the window for the chainstay being machined after the mainframe is moulded. The brake mount area on the chainstay uses the same idea, not relying on aluminum inserts and bulk moulding compound but creating a hollow structure that is post machined to suit the flat mount standard that the Evolve uses.

Frame stiffness also remained high up on the priority list while all this weight was being shed. It’s all too easy to make a really light wet noodle of a bike. Designing around a 55mm chain line allowed the main pivot to grow in width by 60%, even with fitting a 38T chainring. The dinky little slider also played its part, providing quite a boost in stiffness when compared to a linkage big enough to provide the same smooth suspension curves, and allowing ARC8 to take away the seat stay bridge.

With intensive FEA and computer analysis of the layup schedule, the cross-sections of the frame were reduced in areas that had less impact on the overall stiffness of the bike, like the seatstays. However, it’s not as cut and dry as bigger is stiffer and smaller is weaker. With XC bikes using such lightweight structures that common thought starts to fade. Taking into account buckling and the change of shape under load, ARC8 actually used smaller cross sections with thicker walls to give better stiffness and strength in the areas where this common idea of bigger means better didn’t play out. They even shaped the down tube in such a way to stop it from holding excessive amounts of mud.

Overall, they managed to drop the weight by 35% on what was already quite a light frame without sacrificing strength or stiffness. But when comparing the ridiculously low weight of 1775g without shock to the rest of the XC race bikes out there, it seems ARC8 has pulled the pants down on some of the biggest brands in the business while they were all perhaps too concerned about design.

A production Evolve FS in size L weighs in at only 1,775g with shock. Which is impressive on its own, but the geometry of the L surpasses that of even XLs from other brands.

On the scales the size L Evolve came in at just 1775g with a Fox Float DPS shock. That’s lighter than the claimed weights of the Specialized Epic (1869g), Cannondale Scalpel (1910g), Trek Supercaliber (1933g) as well as current (1870g) and previous (1799g) generations of the Scott Spark.

Without any absolute madness is the build specs, that allowed ARC8 to build an off-the-shelf XC race bike at 9.585kg (21.1 lb) with a dropper post and a good dollop of tubeless sealant. That's just over 600g lighter than some of the Scott Spark race bikes that line up to the World Cups. Even with a full Shimano XT build the bike only weighs in at 10.7kg. And this is with frame geometry essentially comparing to an XL size from other brands, which makes it all the more impressive.

With the slider mechanism tucked up against the top tube, it allowed for two water bottles inside the mainframe. There’s even a threaded BB for ease of use and provisions for a chain guide. To top it all off, there’s a SRAM UDH out back and a 30.9mm diameter seat post with 245mm max insertion ready to take a dropper post.

Perhaps the only gripe about the Evolve is the internal cable routing through the headset, something that many of us, in and out of the media, are not big fans of. The Acros unit uses a custom top cap that does blend in neatly with the top tube recess for a clean silhouette. But once the bars are turned, the knife edge like top cap sticks out and makes my knees and undercarriage nervous.






Slider Suspension

Very early full suspension bikes used linear sliding suspension elements (quite the mouthful). They were fraught with shock failures, something we might have too quickly forgotten about with the current prevalence of shock extenders. The switch to linkages was partly fuelled by this, along with advancements in and a better understanding of suspension systems.

Linkages, however, have a big conflict inside them. On the one hand they generally want to be small, light, stiff and easy to package in a bike. But at odds with this is that, generally, longer links give better suspension characteristics. Making the distance between the pivots points bigger tends to smooth out the suspension curves and give smooth changes that can translate to suspension predictability when you’re out on the trails.

But everything is cyclical, and so we’re back talking about linear sliding suspension elements. Something not completely foreign if you’ve followed Yeti’s history. But for ARC8 it gave many benefits for the XC race application.

Early aluminum prototypes were used to validate geometry and other details, but the main focus was on the slider mechanism.
The production version of the slider is a very compact frame element. It uses SKF seals to keep the dirt out as well as Norglide bushings and hard anodized rods for a smooth action during suspension movement.

The slider system could be very small, light, stiff and easy to package in the bike, while mimicking the effect of having a really long linkage. Infinitely long in fact. It also gave some really easy tuning possibilities in development - changing the angle of the sliders alters only the progression. Moving them up or down changes only the amount of travel. For ARC8 it houses Norglide bushings that slide on the polished and hard anodized rods, all sealed up with Swiss made SKF seals.

While the slider is the centrepiece of the bike, The Evolve is technically just a single pivot design, that main pivot defining a lot of the character of how the bike accelerates and decelerates. It relies on a flex pivot out near the dropouts, something now commonplace in short travel and lightweight bikes, but necessary to account for the movement of the seatstays relative to the chainstays.

The slider compresses a 210mm long shock that can use either a 50mm or 55mm stroke to deliver 100mm or 110mm of suspension.

ARC8 Evolve FS LR
The Evolve FS' leverage ratio, red, compared to the Essential, blue. The slider mechanism allowed ARC8 to get a very smoothly changing curve with the longer shock stroke dropping the overall ratios.
ARC8 Evolve FS Anti-Squat
The Evolve's has a good dose of anti-squat.
As well as anti-rise.

It's also a low leverage ratio overall, coming from using a shock usually used to generate much more rear wheel travel. Starting at just 2.1, somewhere that most other bikes often finish, it falls to just under 1.9:1, making for around 10% progression. That low leverage ratio means much less air is needed to achieve the desired sag when compared to a more highly leveraged bike.

With the main pivot sitting a touch higher up than some other XC bikes, there's a decent dollop of both anti-squat and anti-rise in the Evolve, which goes towards combating the effects of load transfer under acceleration and braking. Anti-squat, in a 32/25 gear, starts around 115% and only drops as low as around 95% by the end of the 100mm travel. Anti-rise starts at just over 80% and drops to 60% by the end of travel.






Aggro Geometry & Modern Sizing

Originally three sizes were planned. But once the first riding sample in size M arrived, ARC8 found that riders ranging from 160cm to 180cm were fitting the bike. After some sleepless nights, a lot of chin scratching and measuring, they decided to take the bike to a renowned bike fitter and doctor of the Swiss Olympic team, Andreas Gösele, to get to the bottom of it. In the end, the S size was dropped in favour of only the M and L with their versatile and adjustable, with the different fork lengths, geometry's ability to fit a wider range of XC rider heights.

That M and L size having reach numbers of 477mm and 507mm respectively, that shorten by 12mm when running the bike with a full fat 120mm fork rather than the semi-skimmed 100mm. On paper that’s a big reach, and might bring some preconceptions before riding, but we’ll get to that later. Both sizes are designed around a shorter range of stem lengths than more traditional XC bikes – between 35mm and 70mm. But the stem length also ties into the head angle of the bike.

The steep head angle and longer stem of a traditional XC setup somewhat work with each other. The sometimes twitchy steering from the steep head angle can be controlled with a longer stem length. On the other hand, a slacker head angle can benefit from a shorter stem length to up the directness and speed of the steering. The added benefit being that with a slacker head angle the front wheel is much further from the rider and aids confidence when attacking on steeper descents. ARC8 went with the latter and with a 100mm fork the head angle sits at 66.1°. Put the 120m fork in and it slackens out to 65°. Something usually reserved for bikes with bigger travel numbers and much more of a focus on the downs.

In the middle the BB drops 43mm with the 100mm fork and 35mm with the 120mm fork. That should equate to BB heights of around 328mm and 336mm respectively, depending on tire choice.

Seat angles are 77.1° or 76° depending on the fork, which is a touch slacker than some of the big enduro rigs that the Evolve takes a lot of other geometry details from. But it’s certainly not slack when comparing to other XC bikes that can sometimes be close to 2.5° slacker.

Both sizes have a 430mm chainstay length out back, which goes against the current trends of growing chainstays, especially with such big reach numbers. ARC8 say they did this as they prioritise nimble and quick handling, especially in this short travel category.

Head tube lengths are short – 100mm for the M and 110 for the L. But with a slacker head angle comes a shorter stack height, allowing ARC8 to squeeze the 120mm fork in with a low stack that doesn’t need a wild stem to get into a really aggressive position if that’s your preference.





ARC8 Evolve FS XX1 - €9,999. 9.5kg.

Build Options, Price & Availability

The Evolve is available in three full builds as well as the frame kit. Highlights include Bikeyoke’s Divine SL dropper post and Newmen wheels on all builds, as well as ARC8’s own component brand, Faserwerk, Baslerstab combo on all builds. The Evolve is available to purchase right away, with dealers already having some stock.

The XX1 build is 100mm travel front and back with remote lockout, while the XTR and XT builds use the 120mm fork and 110mm travel at the rear. Framesets come with 110mm travel.


Evolve XX1 - RockShox SID SL Ultimate 100mm fork and SID Luxe Ultimate shock. SRAM XX1 AXS drivetrain. Magura MT8 SL brakes. Newmen Advanced SL X.A. wheels with Wolfpack Speed 2.4" tires. Faserwerk Baslerstab combo. Bikeyoke Divine SL dropper. Repente Quasar saddle. €9,999. 9.5kg.

Evolve XTR - Fox 34 SC Factory 120mm fork and Float DPS Factory shock. Shimano XTR drivetrain and brakes. Newmen Advanced SL X.A. wheels with Wolfpack Speed 2.4" tires. Faserwerk Baslerstab combo. Bikeyoke Divine SL dropper. Repente Quasar saddle. €8,999. 9.8kg.

Evolve XT - Fox 34 SC Performance 120mm fork and Float DPS Performance shock. Shimano XT drivetrain and brakes. Newmen Evolution A.30 wheels with Wolfpack Speed 2.4" tires. Faserwerk Baslerstab combo. Bikeyoke Divine SL dropper. Repente Quasar saddle. €5,999. 10.7kg.

Evolve Frameset - Fox Float DPS Performance shock. Across headset. ARC8 rear wheel axle. €3,299.





Ride Impressions

Back in February I managed to grab some hot laps on the Evolve FS at the Bike Connection Agency Winter event in Tuscany, Italy. For that particular day I also managed to line up half the test session on a race-ready Scott Spark RC before jumping across to the Evolve FS. Both bikes have XC racing firmly in their crosshairs yet go about it with drastically different strategies. And while a handful of runs is usually only enough to tickle the initial ride impressions, I wasn’t quite ready to have my socks blown off the way I did. ARC8 has created a monster of an XC bike.

While the on paper reach can bring some preconceptions about the ride feel, the low weight of the bike allows the bike to dance about with such ease and sprite. With such a low weight, the really long geometry is much easier to manage and manoeuvre. Spending most of my time riding downhill or enduro bikes, the position of the Evolve feels very familiar. Asked to shut my eyes and put my hands where I think they should be on the bars and I’d likely be within a mm of the ARC8. That familiar feel to bikes with more travel is no surprise when looking at the geometry, and probably helped a lot with feeling so at home so fast. But ARC8 was keen to point out that riders coming from long carrers racing XC, while apprehensive looking over the geometry, were won over quite quickly with the bike's handling and the benefits that they were getting from the really modern geometry. At the races, the bike has already claimed a top 30 position in the Elite Women's field at the recent Albstadt World Cup.

The bike and the slider suspension feel is very taut and direct, but not at all to the point that I had my fillings rattled out. You can feel that there’s not all that much travel, especially when jumping between bigger enduro bikes, but it handled the 110mm with brilliant composure and gives good suppleness to take the sting out of the trail and give nice traction while handling bigger trail features and rider inputs with buckets of support.

The mix of short travel combined with the really aggressive geometry creates a ride that is hard to put into words, in a good way. The bike’s shape eggs you on to push faster, to pull up off things that shouldn’t be pulled off and the tiny amounts of suspension does a fantastic job of keeping up with it. But when things get really spicy, and where it’s hard to substitute for more travel, the geometry lets you get away with murder. I think I was just as surprised as the guy in front, who had 60mm more travel, to be following him without much of a problem. The fact that he was on the wheel of Olly Wilkins might give an idea of the speed that this little machine can be capable of. After only a few laps I was a little taken aback by not only how comfy on the bike I was, but at just what it could do.

It was a great place to spend some time in the saddle, pushing hard on the pedals. The seated fit is comfortable and upright enough to never feel like you’re hanging over the back wheel. Which is good, as the front wheel is a lot further away than it was on the Spark. But there was no need to be doing big shifts in position to keep weight on the front wheel, even on steep and slippery climbs. And push on the pedal with any form of pressure and you certainly feel like it’s all going into propelling the bike forward. Much of this feel comes from the really supportive and direct feel of the suspension, which with its low leverage ratio and good dose of compression damping meant that I had no desire or need to use the shock’s lockout. One less thing to think about when you’re breathing out your arse and mashing the bar controls as you crest the climb. But then the XX1 bike does come with a remote lockout, which does make sense for proper XC racing.

As enduro bikes have progressed, their influence on the trail segment is clear to see, and something that we've all benefited from with just how capable the bikes are. And perhaps I wasn’t alone in wondering what a bike with even shorter travel would feel like with the same geometry. ARC8 have not only answered that with the Evolve FS, but also used some well-thought-out solutions and engineering to make a unique bike that may be more impressive than a lot of other XC and downcountry bikes on offer at the moment. And perhaps for a while to come.







216 Comments

  • 327 7
 Whoever started this trend of cable routing through the headsets in MTB, needs to be permanently plagued with subtle brake rub noises that refuse to go away.
  • 14 3
 conspiranoia dictates LBS mafia lobbied to increase the normalized KPI of trips to LBS/person/ 1000 ride hours.
  • 15 103
flag Compositepro (May 30, 2022 at 12:25) (Below Threshold)
 so basically its a crap supercaliber
  • 90 4
 @Compositepro:

If by crap, you mean lighter, longer travel, and with more modern geometry - then yes.
  • 4 94
flag Compositepro (May 30, 2022 at 13:44) (Below Threshold)
 @hllclmbr: pretty much all those things I don’t want so yes really it’s a poor substitute
  • 30 4
 @Compositepro: it’s not a substitute, it’s another option
  • 2 95
flag Compositepro (May 30, 2022 at 13:51) (Below Threshold)
 @hllclmbr: read the part where I said all the things I don’t want , hence not an option
  • 33 1
 @Compositepro: who rattled your cage?
  • 16 20
flag dthomp325 (May 30, 2022 at 15:55) (Below Threshold)
 It’s because exposed cables cost a couple of watts in the wind tunnel. Maybe a negligible difference, especially for a non-pro mtb rider, but I’m guessing we will continue to see this trend on WC capable XC machines where XCO riders are separated by a few seconds on the podium.

I wouldn’t be surprised if aero enhancements start to hit ews too with frequent tight finishes there.

I’m sure DH teams already to aero testing, which is perhaps why many riders run narrower bars than you might expect.
  • 26 1
 @dthomp325: putting holes into bike frames steerer tunes costs more money then a plastic headset that's why.
  • 79 4
 Quick industry memo: make sure you check your design objectives with @Compositepro before starting out. The aim is to standardize all design around the preferences of one rider.
  • 4 1
 @chaoscacca And a creak that's impossible to get rid of.
  • 2 48
flag Compositepro (May 31, 2022 at 0:30) (Below Threshold)
 @Hayek: yawn
  • 2 40
flag Compositepro (May 31, 2022 at 0:31) (Below Threshold)
 @enduroNZ: what would it have to do with you?
  • 3 48
flag Compositepro (May 31, 2022 at 0:32) (Below Threshold)
 @Hayek: or if your going to target one individual with a follow up make sure you know wha tthe requirements for that person are at least
  • 5 0
 Or worse, wandering point Shimanos
  • 10 3
 @Compositepro: sounds like no one cares that you’re stuck in the past
  • 5 3
 @Compositepro: you’re
  • 2 21
flag Compositepro (May 31, 2022 at 8:15) (Below Threshold)
 @Chondog94: really I think maybe I’m happy so who gives a f*ck
  • 2 21
flag Compositepro (May 31, 2022 at 8:16) (Below Threshold)
 @Hayek: yawn
  • 1 3
 I think we've lost the battle for external routing in mountain bikes.
  • 3 0
 @Vindiu: Isn't that all shimano brakes ?
  • 2 2
 @Compositepro: ummm, since we’re (you’re) being picky, if it’s not an option, then it can’t be a substitute.
  • 2 9
flag Compositepro (Jun 1, 2022 at 2:04) (Below Threshold)
 @rmt: it’s way more interesting all the utter cockends a that piled on whilst the geometry is being torn to pieces in the comments below the mob might be fickle but it shows some are also thick as f*ck
  • 1 0
 @You2: All those I have used, but I have not ridden all Shimano's range.
  • 120 11
 A less proprietary lighter Trek Supercaliber. Nice work. Trek steals enough concepts from other people glad to see someone turn the tables.
  • 53 1
 "How the turn tables"
  • 135 4
 For XC there is an elephant in the room that no bike review has ever talked about: *pedaling position* and biomechanics. Trek kept their eff. STA at 74deg because top WC riders have a well defined seating position relative to BB they need to produce peak wattage. Adding 3+ degrees to STA can move saddle centimeters, not just mm, ahead of BB, disrupting pedaling efficiency & putting unaccustomed stress on joints & tendons. I'm no WC pro, but jumping from an older bike w/ 73deg to new bike w/ 77deg STA disrupted my biomechanics enough that chronic knee pain returned for the first time since I painstakingly optimized saddle position over 2 decades ago. TLDR punchline: for average riders, shifting saddle forward may improve weight distribution on climbs, but it can disrupt power delivery and biomechanics to a degree the world's top athletes are not willing to accept.
  • 14 2
 @powturn: same here. That’s why I keep looking for bikes that hold on to the more “normal” XC geo.

Hump
  • 23 2
 @powturn: Agree. The SA is quite steep for a short travel bike. 77* STA compliments long travel bikes that sag a lot under climbing. This XC rig wont. A design STA of 74.5 or 75 would be sweet spot IMO.
  • 17 10
 @powturn: didn't you read??? This is MODERN GEOMETRY


also definitely needs to be longer, lower and slacker :ROLLEYES:
  • 3 0
 @garrettstories: I did wonder this myself , it has a proprietary system behind the shock with more moving parts?
  • 7 4
 Better geo than the Supercaliber too. I would be on a Supercaliber if it weren't for the HTA.
  • 24 4
 @powturn: I really think the "optimal" seat angle has a lot to do with how steep your climbs are. To achieve comfortable (and efficient) pedalling position on a steep climb I need a lot steeper SA and saddle tip tilted down, compared to mellow climbs or flats. The tradeoff is that on the flats I get pushed onto the bars and carry more weight on my wrists.
The "biomechanics" you speak off are (specifically in this case, and obviously within some reasonable limits) a question of habit. XC racers train a lot on road, hence their comfortable/efficient ass-to-feet position is also influenced by conservative road bike geo
  • 3 1
 @powturn: While I completely understand your point, can't position be optimized for a steeper STA?
  • 4 0
 @mgs781HD:

Within a range, yes.

I’ve got a gang of bikes that all have the saddle in the same spot relative to the BB, and I’m real sensitive to changes.

I couldn’t comfortably ride this bike because even with a 9point8 1” setback post (even hillclimbers want a dropper, these days) my position would be .6” too far forward for my liking.
  • 7 0
 @powturn: I've noticed some XC riders have their saddles slammed all the way back. Bec McConnell has the saddle on her Mondraker pushed all the way back. There are some other riders in recent bike checks that also have their saddles pushed pretty far back. If you look at the bike checks at WC XC races...it's something you'll start to notice.
  • 7 0
 @pospist: One other thing that makes a difference is how high a saddle position a rider requires for a given bike. It would be far better if they would publish an effective seat tube angle at different saddle heights, especially for us relatively long legged folks. For example, my XC HT is an XL size with a 72 degree published seat angle with my fork length. It's perfect as is. My new trail bike (Stevo) has a 77 degree seat angle, but I got a size S3 (M) with a super-long dropper and at that length it is close to ideal.
  • 4 1
 @powturn: get a setback saddle and ride a size down bike. You get your reach, pedaling position and modern hta.
  • 2 0
 @abtcup: that's because her mondraker has a steep sta
  • 16 1
 @powturn: Preach it. The seat tube angles are getting ridiculous for actual, you know, pedaling. I used use zero offset posts and to push my saddle full forward to find my best riding position, now it's all the way back and still too far forward. I'm pretty damn far from World Cup athlete, but it's still nice to have a position for putting down the seated power.
  • 2 0
 @Clink1983:

That’s what is being said here
  • 2 0
 @abtcup: Speaking of Bec. Where is her bike check? Her bike is awesome
  • 3 1
 @hllclmbr: I work nights, my brain isn't working.
  • 1 3
 @garrisond5: I’ll look, but I’m happy on my Mach4SL

Hump
  • 2 1
 @Thirty3: There’s a YouTube video she did on her bike.

Hump
  • 3 4
 @mgs781HD: I’d be on a SuperCaliber if it wasn’t a TREK. I raced TREK road bikes for a while and I just can’t bring myself to go to the MTB.

Hump
  • 11 1
 Finally people start to understand that steep SA is not for all types of bikes.
  • 13 0
 @powturn: I was wondering about this too. The weight distribution issues that steep seat angles are intended to address are less of an issue here in general for a variety of reasons, and most serious endurance riders (ie roadie/XC) would only encounter a seat angle like this on a TT bike where getting the smallest frontal area means it's needed to keep the hip angle open enough. And there it's a tradeoff between power output/pain tolerance and aerodynamics.

To be totally honest I've never seen much advantage even on an enduro bike. Old school ~73 seat angles climb just fine for me with all the usual long/slack up front, even when things get steep. But maybe that's just me.
  • 4 1
 @waltworks: why not keep the hip angle open on your XC that will also descend comfortably for a taller person soft-pedaling, but not sitting bolt upright at 150mm saddle drop? The HTA complements the STA complements the reach. Besides, TT bikes tend to have negative seat tube offset at bb, and STA still depends on leg length--generalization is difficult at best. Evolve can also be equipped with a 210 x 55mm shock for 120mm of travel. That differentiates it from even R.M. Element. I'd like to set one up with a 70mm riser bar and test the FEA on seatstays and slider, which looks easily replaceable

@mm732: this bike will eat Supercalibers descending
  • 8 2
 @powturn: Agree. The steep seat angle trend is not good for pedaling power. It works for spinning up fire road climbs with just your quads, but it’s not a good position for engaging the other muscle groups involved in a firm pedal stroke.
  • 13 2
 Just want to point out the fact that this is an echo chamber thread and not representative of everyone. I am completely in favor of steep seat angles paired with long reaches. It works better for me to put the power down. Otherwise I’m pushing forwards off the back of the bike; it’s not the best angle for power delivery and kills my back on the climbs.
  • 2 7
flag Here (May 30, 2022 at 22:56) (Below Threshold)
 @hllclmbr: You'll notice 15mm of saddle position? You must be mad sensitive. More so because your body will adapt over time.
  • 9 3
 @powturn: Where's the scientific proof that steeper seat angles lower peak wattage?
  • 3 1
 @waltworks: I think we are all missing the thing that a ~73 ST means nothing on a FS frame, especially longer travel and also that it's not ST that really matters but the riders position relative to axles and BB, and thus a 73 deg frame is totally different for a 170cm and 190cm guy (given that only recently companies started adjusting the CS length). Comparing ST with road bikes or HTs in general is a little bizarre. On FS frame the steeper it gets the slacker effective angle becomes. So on a 20% ascent your 7deg "super optimal for power output" ST is not 73deg anymore by any means. A 160 enduro bike with 73deg ST is a total pain to pedal uphill and everyone who tried steeper ST knows that, but is definitely is much less comfortable on a flatter terrain.
  • 2 2
 @powturn: like I said above
  • 6 0
 @lkubica: yep. On FS bikes, the rear squats and the front rises in climbs, slackening all the angles. And the more travel (and softer suspension) the more pronounced this is. Hence "winch and plummet" enduro bikes needing steep STA. Short travel XC race bikes don't slacken as much, and XC has historically been flatter, and if there's a steep climb, those guys and gals are out of the saddle pushing many hundreds of Watts. With modern XC race courses starting to resemble enduro stages, this sort of geometry makes sense. But probably doesn't for amateurs riders that still ride traditional XC. Perhaps time for them to just embrace gravel...
  • 4 1
 @SintraFreeride: If you go to any of the Timetrial forums this same topic will have been discussed by several hundred of the worlds best armchair TTers
  • 3 2
 @powturn: But isn't it that steeper sta help all out efforts? most road bikes are similar to 74, an TT bikes are 77ish, so I'm not convinced the biomechanics will be compromised for putting the hammer down. Especially if you running the huge drops that most elite XC riders are on most bikes which "steepens" the seat angle anyways and pelvic rotation anyway.
  • 15 0
 @powturn: it always bothers me when bike media doesn't use an XC racer to test an XC race bike. I know @dan-roberts is a decent rider, but unless he's regularly popping his eyes out of his head on an XC course he may take things away from a bike that are good for him but not the intended user.
  • 6 7
 @lukeb: I get where your coming from, but this is a gravity focused website. Chances are that people on here reading this review, who might be thinking about a bike like this will have an enduro, downhill or trail bike and want something lighter/faster, rather than seasoned XC whippets who want it as a race bike. If I'm right, then Dan reviewing makes more sense to the reader than words by someone with shaved legs and less body fat than an anorexic supermodel
  • 4 1
 @neoides: TT bikes deliberately trade power output for aerodynamics. Not useful on a mountain bike, in general.
  • 1 2
 @chUNdah-luVAh-69: your taint is probably sore if you're pedaling with your hamstrings
  • 1 0
 @powturn: Besides the seat angle, another setup trait WC XC racers tend to do is slam the front end as low as they can with custom stems. Much more so that you tend to see on a typical trail bike or even a factory issue XC race bike.
  • 4 1
 @mgs781HD: @mgs781HD: your most powerfull leg movement is climbing a step. No more, no less, just enough to engage all those big muscles of the leg. Our pedaling mimics that movement, so we can use those super strong and resilient muscles while we are seated.

The steeper seat tube angle for enduro machines are designed to do steep climbs, because when you angle everything right, with sag, on a climb, the effective seat tube angle in relation to the bottom bracket, comes back to those of a road bike on paper.

If we got up smooth roads with not a lot of angle before the steep shuttles back down, enduro rigs would've evolved to have the same slack seat tube of before. Biomechanics is something we can't change.
  • 8 0
 @Notmeatall: I've actually tested this (in the garage)....I had a fit done on my road bike with std. angles, they always set the bikes up on flat ground. So I figured out a typical angle a MTB climbs, jacked up the front end to that angle and reset my BB to saddle height, saddle behind BB and saddle angle to match my road position. Figuring if I spend MOST my times on big climbs, that is the position I want....worked great on steep climbs but was miserable for the flat sections....I think a compromise was best which seems to be in that 74-75 STA and nose slightly down.
  • 3 0
 @powturn: 100% agree. Once I start mountain biking for the season and spend less time on the road bike, a whole new set of muscles start engaging and if I return to the road bike I notice my usual knee pain immediately. Not inherently a bad thing, the two bikes will obviously have to engage different muscles, but modern mountain bike pedaling positions are incredibly quad heavy.
  • 1 0
 every other bike on the market looks like Session and yeah Trek steals for sure Big Grin
  • 3 1
 @blackthorne: You are the only one making sense here. I've been a seat all the way forward, powerful rider for decades, and your unequivocally need to be over the BB more for more power, and especially to use your glutes.
  • 1 0
 @waltworks: that's the front half not the back half that makes the output cost. And with modern high arm positions this gap has been closed signifigantly. But apart from that, have you ever noticed how on climbs people maxing out go "on the rivet" its the same principle for the pelvic rotation.
  • 1 0
 @powturn: exactly.
Got it now with my 2018 Ep8c, in comparison to the 2014 Epic.
Got me into troubles..
  • 1 0
 @powturn: this is true. Pedalling position is quite an important factor to XCO and XCM than to enduro or other catergories. That said I’m not convinced the seat tube angle is all that limiting as more and more roadies, XCO and XCM racers are opting for more forward over the pedals seated position. This shouldn’t shift too much onto the wrists provided the bar height and actual reach is correct for the rider.
My road bike has a 76degre seat tube angle with a 25mm set back post. Depending on whether I’m holding drops or tops I have enough freedom of movement to engage hamstrings or quads at will. It’s not a big problem. What concerns me is the long wheelbase for the medium at 120cm which is similar to a medium Ghost Lektor FS. For me it’s just too long so would consider an angle set to steepen the HA and shorten the WB
  • 1 0
 @abtcup: all the way back or all the way forward? I do t see many with saddles as far back as possible I.e. clamped on the forward section of rail
  • 3 0
 @golefty: 76 deg seat angle with 25mm of setback (for a normally proportioned average male)... you're right back at ~74 degrees.
  • 2 0
 @golefty: Slammed all the way back.
  • 1 0
 @abtcup: Luca Schwarsbaer (sp) has his slammed all the way back on his Canyon team bike

Hump
  • 1 0
 @HumpDiesel: this is great news for all riders who are Luca Schwarzbauer

Also: www.fairbicycle.com/product-page/drop-best
  • 1 0
 @abtcup: they can't really run long and low positions on most bikes because they are too short and the stacks are too high. Not saying they would all opt for this geo, but they could with stacks so low.

In theory you should be dropping the handlebars if moving the saddle forward just like a Tri bike or whatever. All the angles (hips, knees, shoulders) should be the same but there would be way more weight on your hands.

Remains to be seen but I think this and the RM Element seem too long and slack to be useful on a technical climbing course, but what do I know.
  • 76 20
 Gave up reading as I couldn't tell if this was advertorial, editorial or a third person recount of first person content. Nice looking bike though!
  • 6 0
 "The proselytizer of causes overtaken by history and events." Paul Keating.

This phrase was on loop in my head while reading this article.
  • 5 29
flag plustiresaintdead (May 30, 2022 at 9:52) (Below Threshold)
 Definitely paid placement. Gotta pay the bills!
  • 30 5
 @plustiresaintdead: Absolutely not. Dan has lots of respect for the Arc8 folks though.
  • 22 2
 @brianpark: undoubtedly, but perhaps the article should be prefaced with how Dan came to have those insights as to their design decisions taken, how Dan knows what their thoughts were and where the very specific numbers were obtained from.
Reads like "Inside+" knowledge Wink
  • 74 2
 @juanny: we met with Dan twice over the last 3 years. All the insight he shows here came from 1 hour of product presentation/discussion and chatting after his test ride at the Bike Connection event. If he shows a lot of insights than probably because he is an engineer himself and asking smart questions.
  • 12 0
 And here I was thinking, as I was reading this, that he really just loved this bike. Silly me.
  • 6 3
 @ARC8: Cool. that's paragraph 1 right there Wink Easy
  • 3 1
 @juanny: I think you mean "Outside +"
  • 4 0
 @ARC8: please name one good reason for that headset if you can

Cheaper manufacturing and "looks" aside.
  • 14 7
 @JohSch: It works equally well, no matter which hand operates the rear brake. Also, going internally with the cables at the main pivot allows us to go much wider with the frame in this area which results in better stiffness and less load on the bearings. But it does not allow for internal tubes that guide the cables. We could never do an opening as big as the bearing seat just to get the cables out, so it is actually the easiest solution for cable installation as well. And reducing manufacturing complexity is not only a good thing for cost but also quality and performance.
  • 20 1
 @ARC8: Those are good reasons. A counterpoint: PEOPLE HATE THEM.

Sure, it adds a few grams to create holes large enough for all cables and all brake options, but if companies have created openings large enough to fit an American-sized burrito into the down-tube, I'm sure you can manage a few cables and hoses and remain under the (arbitrary, but marketable) 4 lb mark.
  • 7 0
 @ARC8: because of your main pivot design (=near seat tube) you had to use a specific headset (=front of the bike)?!

Which is prone to getting loose and creaking as any plastic (across) headset, (see Cube Stereo 170 or Canyon Spectral for reference).

let's water and dirt in which kills the headset bearings - which will be hard to get as spares, at least in a few years time judging from acros past. And which are harder to replace with all what's going on there.

You let the cables rub the fork steerer and further back the mainframe, make it harder to change stems, spacers and cables and impossible to install a proper headset.
  • 3 0
 @ARC8: +1: do you have a picture of that bike with no spacers and a negative stem and a cable operated dropper and shifter as many XC racers would ride it?

What happens with that headset and all the cables in that very typical szenario?
  • 49 1
 Pinkbike. You have the power to stop the madness regarding cable routing through the headset. If you can create a whole new segment of bikes (down country) you can stop the industry from ridiculously and needlessly routing the cables through the headset. You have the power and now use it for good.
  • 1 0
 Was there a survey about headset cable routing lately, or was that just internal frame routing?
  • 14 0
 It's lovely. As I age my bikes have grown less and less aggressive on the spectrum. I've slowly moved segments from freeride, to enduro, to aggressive trail bikes currently... This will be my target segment in five to ten years, until death.
  • 8 0
 I'm moving in the opposite direction.. of bike spectrum, not life. That would be weird.

Started with 26" ht that had 72° ha, 11 cm stem and 620 mm flat bar. And horns. Every next bike was slacker and longer and more capable than the last one.

I'm kinda scared of the bike I'll be riding 10 years from now..
  • 4 4
 .....Dosent the aging progression go from Freeride, to Enduro, to Trail, to Down Country, to Gravel and then finally onto something E (not xc)?
  • 11 0
 @threesixtykickflip: no.


Old dudes still shredding ‘round here.
  • 3 0
 I’ve gone with longer travel as I get older to compensate for my arthritic joints not being able to absorb hits and bumps as well. These day, if I do a sesh on my hardtail I feel like a truck ran over me the next day. But, with the 150mm trail bike I can go longer and more often because I’m in less pain the next day.
  • 1 0
 @pakleni: Have you seen how slack the head angle is on a mobility scooter? :p
  • 1 0
 @korev: I did. Actually, I dont know if you noticed but some year or two ago several of them appeared around Luzernerring as a share ride. I wanted to rent one and make few laps in Allschwil. Boring sense prevailed
  • 1 0
 @pakleni: Sounds like you may be on a KTM 450 Enduro motorcycle
  • 2 0
 @HumpDiesel: If that's the future I'm so ready for it!
  • 14 2
 "aggressive geometry"? Surely a tranditional xc bike has more aggressive geo. I'd say this bike has more cruisy, relaxed geo ... sure if you're riding aggressively and miss calculate this will be more forgiving. I guess it doesn't sound as cool to call modern bikes "safer and more forgiving".
  • 3 0
 Spot on. This has become almost as big a misnomer as "clipless".
  • 15 1
 Slider mechanism AND the ARC name have me thinkin’ Yeti.
  • 2 1
 100%. Not only did they use the ARC name which Yeti has used since the 90's, but that slide system had me thinking about the old 303 frames. Man, if they borrowed themes from Specialized, they would have already been in court.
  • 10 0
 Lol and so the ‘progress’ continues…
DH bikes become Enduro
Enduro bikes become Trail bikes
Trail bikes become XC bikes
and gravel bikes are the old XC bikes

The beauty of this model is that it can be reversed in a few years to sell more bikes.
  • 14 2
 This is a pure XC bike. For the love of God, please stop using the term downc*untry.
  • 8 0
 The weight is very impressive. Call me old fashioned for wanting the HTA a touch steeper for tight handling (like 67.5 not a 70 degree death trap). I think they've put a very nice bike together. Except for headtube routing. I'm willing to try the flat mount brakes on the MTB if it genuinely means more speed but they are a bit of a headache in my experience.
  • 8 0
 48.5"/1234mm wheelbase for a size large may be of concern to many XC racers! That's huge. Tough to get through the high speed tight terrain of an XC race. Only world cup XC courses are getting burly, not local amateur races.
  • 16 9
 65HTA works better for mountain bikes.....period. This is one of the first XC chassis to go that way, but it'll likely become the norm in the next few years. Cool to see a company other than Yeti adopt a single pivot slider setup. It's one of the 3 or 4 ways to suspend the rear end of a bike that can work really well.
  • 9 2
 @garrettstories: you have to control for dynamic sag or short travel 65 bikes end up slacker than long travel bikes. And st bikes have less mech grip due to stiff susp and balder tires so you NEED more weight on the front end and thus need a steeper HTA
  • 2 1
 @mm732: more weight on the front wheel is a 10-20mm longer stem away. As for dynamic sag, I'd argue that the geometry of a short travel bike changes a lot less than one with more squish.

Enduro bikes are likely to tick down to around 63 degrees, XC bikes won't go below around 65, but that's where they'll end up.
  • 4 1
 @wyorider: "I'd argue that the geometry of a short travel bike changes a lot less than one with more squish"

Yes, of course, that's precisely what @mm732 is saying. A big enduro bike with a 64deg ha might more closely resemble, say, 65.5deg ha dynamically because it has a lot of squish, therefore the angles change more.

But a shorter travel bike changes less, so you have to start out closer to your dynamic target, eg. with a 66ha to target, say, 66.5 deg.
  • 1 0
 @wyorider: longer stems help but id argue too much caster/rake still loads the tire differently.
  • 9 2
 It's lovely, but for the larger chaps there are almost no more XC bikes to be had. I'm 195cm and have long legs. If the seat tube is shorter than 52cm, I can not fit on the bike. And even than I have very limited choices off seat posts. In my XL Cannondale Scalpel I had to fit a dropper, because with the normal seat post I was sitting 3cm to low. And this goes on with all bikes nowadays. They become to long and to low for tall people to be useful. The only brand I can ride comfy is Cube, and let's be honest, there are more exiting brands to be had...
  • 4 0
 Interesting comment. I have the opposite issue, despite being (quite) tall with long legs. Impossible to fit a long dropper if I actually take a bike which is long enough for me.
  • 2 0
 @EnduroManiac: I must admit, i have a weird body. My inner legs from floor to balls is 106cm. My torso is about the same size as somebody that is about 185cm. My arms from tip to tip is 206cm. So I need a quite short top tube compared to a long seat tube. and wide bars.
I have a Cube, On-One and Rose just for that matter. I could get the Cannondale for free from my work and I had to change stem(shorter) and seat post just to get my position right. I'm riding a 170mm crankbrothers dropper and that post is 9cm out of the frame... In 2018-2019 that was the longest dropper I could get...
  • 4 0
 I agree with. I'm 193cm and the first geometry spec I look on new bikes I'm interested in is now the seat tube length.
Seat tubes for 10 years old kids on big XL and XXL frames is on the same "Annoying" level as those damn internal headset cable thingy.
  • 1 0
 @EnduroManiac: I'm the same body shape and "longer, lower, slacker" is great for me as I can buy a bike that's long enough
  • 2 0
 I kind of think it's the other way. Bike brands are finally making frame geometry that fits me (190cm).

Reach has finally grown so that I don't have to run a >100 stem and a slammed back seat position to get the fit right.
  • 2 0
 @slowSS: I can understand the longer reach for bigger frames, but why do they have seat tubes that would be good on a medium? Tall people have long legs and those short seat tubes really make it difficult to find a frame that fits (me).
  • 1 0
 ridley, check out Cube bikes. Mine is a 23" frame. I'm 6'-4" with a 38" inseam. It fits great.
  • 1 0
 @bikebudha1: I have a cube 23" as well (hartail). Nice bike to ride and fits my weird body perfect. But it would be nice to have more options. I'm now on my second Cube.
  • 1 0
 @RidleyRijder: We seem to be the opposite proportions, my friend. I'm all torso, short legs (relatively) so reach is the issue. Currently running 500mm reach in an XL and it's in no way big.

On the seat tube length, have a look at Canyon Lux/Lux Trail. Everyone was complaining that the seattube extension (545mm in an XL) was too long so might be good for you.
  • 21 14
 I don't care what Anyone tries to tell me I never want a 65 degree head angle xc bike. My current xc bike is close to 70 and it's so much faster to turn than my 66 degree downcountry bike. I hate all this long slack bullshit. Learn some skills instead of riding fatter slower lazy geometry bikes. Ben cathro summed this up well in one of his vids. I wish my downcountry bike had a 10-15mm less reach and was a couple of degrees steeper. I like My xc bikes twitchy but super fast not some slow lethargic straight line stability favouring bike.
  • 16 1
 Luckily for you, there are plenty of bikes that fit your tastes - and plenty of used ones to fit any budget. For folks with preferences on the opposite end of the spectrum, it's nice to finally have a couple options. Not every bike has to appeal to every rider and every terrain.
  • 6 0
 Amen. The bike industry now targets bikes and parts to make average riders feel slightly less average, rather than making fast riders go faster. It's a shift I noticed a few years ago, and it's going into hyper-drive these days.
  • 3 4
 What happens is that as suspension, tyres, etc improve, speeds increase. The limiting factor changes from one aspect of a bike to another, in this case head angle - then head angle slackens and is no longer the limiting factor, so something else gets tweaked. Then the course designers make the descents gnarlier for these more capable bikes, so then there's an advantage to having a dropper seatpost... Then the course designers make the climbs even gnarlier, so tyres have to have more grip, seat tubes need to be steeper, lockouts aren't as much of an advantage, and so it continues evolving. This happens in other areas too - with e-bikes, pedalling performance is no longer as important, so manufacturers are starting to lower BB height and shortening cranks. Many describe their e-bike as the best cornering bike they've ever ridden. Downhillers are now experimenting with adding weight to the BB area of their bikes!
  • 3 0
 @thingswelike: "Downhillers are now experimenting with adding weight to the BB area of their bikes!"

Has been done for years and years
  • 3 1
 I agree! I ride the previous gen (201Cool of Cannondale Scalpel. That bike has a 69.5° head angle. I've tried the new one 1 month ago and it feels so much more sluggish. And that bike has an 68° HA. Only 1.5° difference, but for a fast XC bike that makes a big difference! For me XC bikes should be between 70,5° an 69°. What also is important, The planet is not just a mountain. There are flat parts in the world and downcountry bikes have no place in flat places.
  • 6 1
 Good to see XC bikes growing, I have already had the opportunity to realize that this is the way to go. And, I'm not sure if everyone is aware of this, but with a lower stack comes a longer reach (to maintain the same BB to bars distance), so XC bikes must always have more reach than enduro or trail ones.
  • 4 0
 Impressive weight. Not sure how I feel about that slider. The combination of a flex stay and fixed slide path has to create some stiction. No surprise this puff piece still pointed out that it's stiff in the back, and that's with a clean bike. How's it do covered in mud? Cable routing needs to allow for standard stems and bars, mechanical droppers, and to remove brake hoses without cutting them in two. If any of that isn't true, it's a non-starter for me.
  • 4 0
 I am 5'8" and the medium is too big for me. 25mm more reach than my E29 and I have a 45mm stem on that (and it fits me perfect)!

Just bought a new XC bike with a 420mm reach, I would be okay with another 10-15mm, but this is the most fun XC bike I have ever owned.

And they don't want to go smaller?
  • 6 1
 I think that geometry would make me do stupid stuff with that bike that would lead to breaking it
  • 4 0
 Very cool bike but what’s up with a frikkin’ 465mm reach on a medium and of course those cables running through the headset……?
  • 2 0
 A lot of XC people seem to have something against the STA and HTA. I am happy that we are finally getting XC bikes that might not put me right over the rear hub and XC bikes that suit different styles of riding. If anything then I actually think that a steeper STA has improved my power both on the flat and on climbs, but a effective STA of 76 or 77 is only going to be that if you have your seat height right where they measure, a lot of people are going to end out with a slacker one. Yes a steeper STA might feel weird on the first few rides, but I really think it's worth it for people to give them a shot, I have had nothing but positive experience with mine. The sizing range seems optimistic, but I would welcome a XL especially if they increased the CS to make it more balanced. Honestly just to make it handle more like its smaller counterparts, instead of needing to have the front weighed down more all the time.
  • 3 2
 There are a few bikes out there that use a swing-link, i.e.SC Blur , that have minimal arc and seem to work quite well so I'm not seeing a real benefit to a potentially high maintenance slider. Nice looking bike for what it's worth.
  • 4 0
 It seems like a pretty simple element though. I can't imagine maintenance to be too time consuming, even if it has to happen relatively frequently.
  • 15 3
 Trust us, we tried. The Essential uses pretty much the best compromise we could achieve with a swing link, but it would not allow for a second bottle with a low standover, it needs a horst link because the deformation without would be too big, and we could not achieve the same linear-progressive ratio. Most competitor bikes with a swing link and flex stays we analyzed tend to be digressive.
  • 2 3
 @ARC8: Your bike may be the best XC bike ever made, for all I know - I'm certainly fond of the geometry - but a Rocky Mountain Element can fit two bottles inside the frame - maybe three, on the larger sizes, if they added a top-tube mount? - the Cannondale Scalpel fits two, Huizhou Flybike, Orbea, Specialized ... there are loads of XC bikes that can fit two bottles inside the frame with a suitably low top-tube and swing link with a rising motion ratio.

(Some of the aforementioned bikes have a tall seat-tube by choice, not because they needed the room for packaging.)
  • 5 1
 It slides just like a fork, has great access for cleaning, and is out of the firing line for mud, dust and falling sweat. I can't see a problem.
  • 7 1
 @Joecx: Does the Santa Cruz link create lateral load on the shock like mentioned by Vorsprung? Funny how Santa Cruz spent twenty years telling us VPP was the bee's knees. Then they decided to sponsor a world cup XC team. The fast French guy said um, not fantastique. Why don't you just look at this old 2015 Scott Spark or this Cannondale Scalpel that I have in my garage. And don't forget the handlebar lockout. OK? merci beaucoup.
  • 3 0
 @Baciatutti: The link has a fairly wide pivot point at the top tube and the shock bushing doesn't have much rotation so I can't see how it would load the shock in any direction but compression.
  • 12 1
 @R-M-R: not saying these bikes do not work. But developing a bike means picking the best compromises to achieve your goals. We felt in our case, going with slider is that.
  • 5 9
flag R-M-R (May 30, 2022 at 20:01) (Below Threshold)
 @ARC8: No one claimed you said your competitors' bikes do not work. You said "Trust us, we tried", which, given the context, I take to mean you tried to accomplish your design goals with a swing link, but could not do so.

You went on to say "[...] but it would not allow for a second bottle with a low standover, it needs a horst link because the deformation without would be too big, and we could not achieve the same linear-progressive ratio. Most competitor bikes with a swing link and flex stays we analyzed tend to be digressive."

Now that @Joecx and I have demonstrated that many of your competitors have succeeded in doing what you "tried" to do and how unlikely it is that "Most competitor bikes with a swing link and flex stays we analyzed tend to be digressive", I invite you to discuss your design process further. You've created an aesthetically pleasing bike with forward-thinking geometry at an impressively low mass, but your packaging and kinematics claims are demonstrably false. I wouldn't fault you for choosing the sliders for the reasons Dan mentioned in the article or even for the novelty of it - it's already generated enough press coverage to justify the choice.
  • 12 1
 @R-M-R: exactly as you say it, we could not achieve our goals without the slider. It would need a higher top tube, be heavier, or have a less than ideal suspension ratio. Not all of it, but at least one.
  • 1 0
 @Baciatutti: and then rides the new bike into 2nd place, his best race ever just losing in the sprint finish to the worlds best xc racer.
  • 6 0
 Nice ad.
  • 1 0
 I really like this bike and was really hoping to see more progression and definitely longer CS length as I went through the review.

Maybe a DC version could be built and add these bits in?

Bash guard provisions would be nice as well.
  • 1 0
 Good job combining long reach to short top tube. For more trail oriented riding this does need high rise bars or hefty stack of spacers under the stem. XT build is really nice including integrated bars/stem, altought i personally prefer RS suspension. Pike+Deluxe combo would be killer on this!
  • 3 0
 @ARC8 I need a XC bike to complement my Enduro, but can we actually purchase your bikes in the USA or North America? Do you offer online sales?
  • 2 0
 Unfortunately our online shop is currently down (bad timing, we know), but we are working on that. Meanwhile, you can use the contact form on the website to inquire about buying a frame from us.
  • 1 0
 I have not ridden a flex stay bike, so a question for those who have is, does the rear end get all floppy with lateral forces? Seems like the stays would allow the wheel to move from side to side. Serious question, don't kill me.
  • 1 0
 I ride a Canyon Lux since four years now and I can't feel any lateral forces. You don't feel the flex stays. Also a road bike or gravel bike also has flex stays if you will. The beauty of carbon is that it can be designed to allow for flex in certain directions and prevent flex in other directions.
  • 2 0
 @juuro: don't remember which podcast, but I remember hearing a road/track bike designer (from Felt maybe?) saying that modern carbon road bikes basically don't need seatstays. The UCI requires them, but all the stiffness they need comes from the chainstay-BB area. Which is why so many of them now have pencil-thin dropped seatstays.

Obviously for a FS mtb the chainstays actually do take the force that actuates the shock, but that part where the chainstays join together around the pivot axle is probably torsionally stiff enough to resist major wheel tilt under cornering.
  • 1 0
 Lightweight and burly trail bikes with long reach are what I like. What I see missing from the market are suitable forks. I recently upgraded to a Lyrik and used the Jari air shaft kit to reduce the travel from 150mm to 130mm. It's pretty awesome that Roxkshox enables this, so kudos to them. My point is that it would be nice if the Lyrik and other enduro level forks were available at 120 - 130mm travel off-the-shelf. (and a lock-out option would be nice too).

I'm pretty sure this Arc8 would be even more awesome with a Lyrik instead of a SID.
  • 5 1
 Nice classic lines I dig
  • 2 1
 That is definitely some forward thinking xc geo, if xc settles at 65 HTA where does that leave enduro bikes? With those reach numbers soon the main differences will lie in frame weight and components.
  • 5 0
 Enduro bikes will have longer chainstays, lower bottom brackets (you’ll have to run 165 cranks), and a lot more travel-and also HTA closer to 63 degrees.

Even now, bikes like the Enduro, Slash and Megatower are slack enough to me more or a race tool than an ideal daily rider.
  • 2 0
 Good to see XC race bikes with good CS to WB balance. 430mm CS goes well with ~1210mm WB on longer travel 29ers, I found. My fav is still 435mm CS with 1230mm WB though.
  • 3 0
 That AS for a 32t chainring is not impressive, considering that a lot of XC riders use 34t.
  • 7 0
 XC race bikes often have lower pedaling anti-squat than trail and enduro bikes. Not that I think they should, just saying it's common. There are typically two reasons for this:

1. The traditional belief that 100% anti-squat produces zero squat from pedaling. Most designers have discovered it's more complex than that, but some still cling to the idea.

2. Lower pedaling anti-squat produces lower kickback while pedaling. Some racers are willing to accept a little more bobbing in exchange for less kickback while pedaling.

Bonus third reason: Many racers set up their suspension super firm to reduce unwanted movements when pedaling, which mostly eliminates suspension movement from low pedaling anti-squat. They may not need to use such a set-up if they had more anti-squat, though it's difficult for anti-squat alone to eliminate unwanted movement while seated and while standing.

On average, pedaling anti-squat levels are coming down across all categories due to the recent fixation on pedal kickback while descending. Personally, I think that concern is overblown and we'll swing back toward more pedaling anti-squat in a few years, but the evolution of the industry's preferences in kinematics is an article unto itself!
  • 3 0
 Problem with this article and this bike is that the new Spark has already been released.
  • 3 0
 Looks good for a 24hr race or most UK trail centres. Best start saving for n+1
  • 2 0
 very interesting xc bike - looks like some well-sorted build kits as well. No option to order in the USA though?
  • 1 0
 I've been emailing with Arc8; they confirmed there are not (yet) any US based dealers or distribution, but did mentioned a bike or frame could be ordered direct from them and shipped. I then followed up by asking a question on how a potential warranty would be handled, or even what the warranty is because I didn't find any warranty info on their website, and I haven't gotten a response to that one yet.
  • 2 0
 First review I’ve read in a while with DOLOP used twice.
Make DOLOP great again.
  • 3 0
 Almost looks like a Supercaliber
  • 2 0
 While I have no interest in buying an XC bike, I will say this is one nice looking bike.
  • 1 0
 Everyone losing their minds about the reach while the top tube length is still only 612mm in the medium….,
Me thinks precious few understand bike fit.
  • 1 2
 The thing that really SUCKS about 'race' bike like this is the single chainring up front. No of "us" are pro racers. And bikes like this will be ridden many a mile over many a hill. So it would be really nice to at leat have a "double" ring up front for us mere mortals as we tackle those longer epic rides. (I have a Brek Epic belt buckle, and I can't imagine having such limited gears for a ride like that. I did the Epic with a triple. It saved me.).
  • 2 0
 Horribly low stacj height. Tall people with long legs look elsewhere
  • 2 4
 Lol at some of the geo comments here. Roadies, erm, I mean XC racers are such a traditional and conservative bunch. "Nothing wrong with 73deg parallel, grumble, grumble". Modern geo doesn't(didn't) seem to be holding back Gwen Gibson on her Norco Revolver FS.
  • 2 0
 Any chances of an XL in the future?
  • 1 0
 The bizarre geo makes me hesitant to buy before a test ride, but test riding is impossible.
  • 5 7
 >Jonas, one of the main men behind ARC8, was riding downcountry long before it became a defined segment.

Stop trying to make "downcountry" happen. It's not going to happen.
  • 5 0
 He's right though, the space between thoroughbred XC bikes and trail bikes was occupied, think of something like the Specialized Camber which was a 110mm/120mm weapon... It just took Rocky Mountain and a Levy to slap a name on it and the whole industry has piled in
  • 1 1
 @HankHank: what happened to Canondales' "Overmountain" category? What happened to RC's "black diamond" category?

These niches are getting comical.
  • 2 0
 @SeanC1: Before Overmountain Cannondale used to put "Marathon XC" on their long(er) travel XC bikes. That company has "invented" every niche of MTB'ing you can think of like 20 years ago but all their proprietary stuff has kept them from getting popular I think
  • 2 0
 @HankHank: I keep my Camber Evo as a winter/slop/commuter. Owned it since new, and it still rips. Got a ´21 Epic Evo, and S could just have called it Camber Mk3.

Funnily enough, after doing trail, enduro, gravel freeride, mountains, parks, etc whatever since getting my first Camber in 2014, riding the EE has brought me back where I was then. Just plain old MTBíng on natural singletrack and gnar, with some gravel and blacktop between the good bits. Gone full circle in 8 years.
  • 1 0
 @knutspeed: I have a '13 or '14 Camber Evo (can't remember which) as my only mtb and I'm still really happy with it. I've demoed a few more modern bikes and they're cool, but I'll probably keep riding the Camber until I break something expensive. I'm contemplating putting a SlackR angleset on it to bring it a little more up to date but idk if it's worth it. Thoughts?
  • 1 0
 Beautiful Bike! What’s the units for the axis on those graphs?
  • 1 0
 All of them
  • 3 2
 That's exactly it! We look at the pics and fall in love with the bike's looks just like we all fall in love with beautiful sports cars in magazines or web pages! Then, they show these stupid graphs that don't make any sense because no one really cares. But for a geek like me looking at those graphs, they absolutely mind-boggles me because they make absolutely no sense, especially when they're dimensionless. It's like how do you still get a non-zero ratio at zero millimeters?
  • 5 0
 Horizontal: mm
Vertical: unitless (ratio), or % (anti-squat and anti-dive).
  • 4 0
 @CSharp: Because leverage ratio is slope, i.e. the derivative of the shock travel vs wheel travel equation, and the slope is not 0 at 0mm of travel. For Y=f(X) where Y is wheel travel and X is shock travel, they're plotting Y vs f(), not Y vs X. I understand the lack of units is ambiguous and unprofessional, but come on, it's a 100mm travel bike so it's probably safe to say the x-axes are in mm, AS and AR are always measured in percentage so that's another safe guess, and bike suspension leverage ratio is always unitless because it's travel/travel where both would be measured in the same unit of distance... However, I do get your desire to be pedantic and sarcastic towards ARC8, because for them to say things like there is no way for them to achieve their goals except by using that slider instead of a rotating link, they have either pigeon-holed their goals to a ridiculously narrow focus for the purpose of justifying the slider, or they chose that slider for some other reason such as just to be different than the 100 other similar bikes out there and now are trying to bullsh!t everyone with a scientific justification. Either way, they are coming off as a bit arrogant and unfounded which, as is evident in this comment section, just annoys people and makes them bring up all the other bikes which have somehow accomplished the same or very similar goals as this bike without all the bullsh!t.
  • 1 0
 Do they have a world cup team?
  • 8 0
 We have, but nothing with a budget of the big ones. Goldwurst Power and TB Performancelab were at all European races of the World Cup so far.
  • 1 1
 that rear caliper reminds me of the old 22mm Hayes used on the 1998-2000 Homegrowns
  • 1 0
 2017-2020 cannondale scalpel had a direct mount rear brake caliper
  • 2 1
 The Alu proto reminds me of the Yeti 303 DH bike
  • 3 3
 Looks like A 2012 Scott spark ...
  • 1 0
 Ok cool.
  • 2 2
 They lost me at FLAT mount...
  • 2 2
 Trek Supercaliber was way more dope.
  • 1 0
 Looks like a session
  • 1 3
 a high end carbon frame with cheap china scale ?
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