Review: The Pivot Mach SL 4 Blends XC Speed & Comfort

Dec 12, 2023 at 16:12
by Betsy Welch  
In May, Pivot introduced the updated version of the Mach 4 SL, the brand’s race-focused XC bike. Previously known as the Mach 429, version 3 of the bike boasted plenty of changes to write home about: namely, two fork specs, a flip chip on the rocker link to adjust the rear wheel travel, and a weight savings of 300-400g over the older bike.

Pivot had two main goals with the Mach 4 SL update — to design a lighter and more efficient cross-country race bike for its pro athletes, while at the same time making something capable enough to serve as an all-rounder for recreational riders.

Satisfying both sets of criteria is a tall order but one that is increasingly possible with progressive geometry and suspension design.

Mach 4 SL Team XTR-S Details

• Wheel size: 29"
• Mach 4 SL carbon frame
• Travel: 106 or 115mm, 120mm fork
• 66.7º head angle
• 74.7º seat tube angle
• 432mm chainstays (size S)
• Sizes: XS, S, M, L, XL
• Weight: 24.7 lb / 11.2 kg (size S)
• Price: $9,899 USD
pivotcycles.com

“Basically, we designed the bike to climb like shorter travel bikes with incredible efficiency but descend like a longer travel bike with suspension performance that really enables the rider to stay in control and go faster in technical terrain. With all Pivot designs we try to find a huge range of versatility. Designs that can be, at their core, focused on what their main job is but then also punch way outside their race category,” said Pivot’s CEO Chris Cocalis.

Pivot tweaked a few things on the new Mach 4 SL to give it its chameleon characteristics. Namely, there are four travel options in one frame. Rear wheel travel can be adjusted by a flip chip on the upper linkage. On World Cup builds, this means 95 or 103mm of travel; Team, Pro, and Ride level builds get 106 or 115mm.

I didn’t race any World Cups last summer, but I did do a few races in Colorado where versatility was key. The Mach 4 SL ended up being a nearly-perfect bike for both the six-day Breck Epic and the four-stage (single day) Durango Derby.

My test bike was the $9,899 Team XTR model in size small. In addition to the Shimano XTR drivetrain, the bike came specced with Fox Factory suspension, a Fox transfer 100mm dropper, Reynolds Black Label XC 309/287 wheels with Industry Nine hydra hubs, and Maxxis Rekon race tires front and rear.





bigquotesThe Mach 4 SL’s responsive suspension soaks up all manner of hits, and I found it to be very forgiving for such a lightweight XC bike. Betsy Welch




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Frame Details

According to Pivot, the Mach 4 SL’s carbon fiber frame features size-specific tuning - different carbon layups are used for each size. Visually, the tubes have a smaller diameter than other Pivot mountain bikes, and the front and rear triangles are more compact. All sizes are able to accommodate one large water bottle, and the M-XL frames can hold two. There are two bosses on the underside of the down tube and three bosses on the underside of the top tube.

This version of the Mach 4 SL shaves some 300g off the frame weight of the previous version, due in part to the switch to a vertical shock placement.

The rear-wheel travel of the Mach 4SL can be adjusted by a few millimeters with a flip chip on the rocker link. This gives riders the choice of 95mm or 103mm on the World Cup builds, and 106mm or 115mm on all other builds.

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Geometry & Sizing

The Mach 4SL comes in a 100 or 120mm fork spec, with fairly significant geometry differences between the two. All versions of the bike have a slacker head angle, steeper seat angle, and longer reach than previous versions. The head angle goes from 66.7° to 68° when switching from 120 to 100, with an accompanying increase in reach of about 13mm. Seat tube angles sit at 76° on the 100mm and 74.7° on the 120mm. Chainstays are the same length regardless of frame size, measuring at 432mm.

In terms of sizing, the Mach 4 SL comes in XS-XL frames, and Pivot says the five-size range will accommodate riders from 4’ 10″ all up to 6’ 7.″ Standover clearance is generous across the range of sizes.

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Suspension Design

At a time when many manufacturers are using weight-saving flex stays, Pivot has stuck with a dual-link design. The Mach 4SL continues the brand's use of the DW-link suspension design, known for its efficient power transfer and stable and consistent suspension platform. The design works particularly well for this race-oriented XC bike, where pedaling efficiency is a top priority.


Specifications
Price $9899
Travel 115
Rear Shock Fox Float Factory 2-position
Fork Fox 34 StepCast Factory, 120mm
Crankarms Race Face Next SL, 34T chainring
Rear Derailleur Shimano XTR
Handlebar Phoenix Team Flat Carbon
Stem Phoenix Team, 60mm Length
Grips RockShox TwistLoc Lock-On
Brakes Shimano XTR Race 2-Piston w/160mm
Wheelset Reynolds Black Label 309/289 XC Carbon
Tires Maxxis Rekon Race EXO 2.4
Seat Phoenix WTB Volt, Carbon Rails
Seatpost Fox Transfer Factory


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RIDING THE
Mach 4 SL
Photo: Eddie Clark

Test Bike Setup

I swapped the stock front Rekon Race tire for a Rekon (I wish I had put something bigger on the back, as well) and replaced the uncomfortable Phoenix WTB World Cup Volt saddle with an Ergon SR Pro.

Pro (un)tip: in prepping for the Breck Epic, I mistakenly put the bike in the shorter travel setting, and raced all six days like that. When I got back, I flipped the chip and spent the remainder of the riding season and the Durango Derby with the much more pleasant-feeling 115mm rear suspension setting.

Oh, and the bike also came stock with a 34mm chainring, which I would have very much liked to swap for at least a 32 (that’s on me). I’ll just use that as my excuse for walking up some of Wheeler Pass on stage 4 of the Breck Epic.



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Betsy Welch
Location: Carbondale, Colorado
Height: 5'6
Inseam: 30"
Weight: 134 lb
Industry affiliations / sponsors: Ripton & Co

Climbing

As you can imagine, the Mach 4 SL is a speedy climber. The lightweight carbon frame and DW-Link suspension system ensure that power is efficiently transferred to the wheels, which results in impressive traction and minimal pedal bob. I rarely looped out, even when pausing before technical uphill features.

On paper, the seat angle — 74.7 —seems pretty slack for an XC bike, but in real life, it doesn't feel that extreme. Remember, on a bike like this the seat angle won't change as much at sag compared to a big squishy enduro bike. Plus, the pedaling performance on the bike is just so darn good. In both travel settings, the rear suspension delivers the right amount of sensitivity and you can stay seated on all but the steepest climbs. Traction and control work in tandem on this bike — in fact, I had my best ride of the Durango Derby on the notoriously shitty, loose, and steep Animas Mountain climb. Efficiency is the name of the game on the Mach 4 SL, but there is no hidden cost in pedaling performance.

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Descending

The big question was if the bike could go downhill as well as it climbed. Usually my own toughest critic, I got some really nice affirmations from buddies on late summer rides that I was descending faster than normal. I think this was largely due to the full immersion experience of the Breck Epic, but the bike definitely had something to do with it, too.

The Mach 4 SL’s responsive suspension soaks up all manner of hits, and I found it to be very forgiving for such a lightweight XC bike. The short chainstays keep things snappy, and it’s easy to maneuver the bike through tight and technical terrain. During the 'Colorado Trail' stage of the Breck Epic there's about a mile-long section of really bumpy technical rock garden where line choice is tricky and important. I saw multiple guys sitting beside their upside down bikes during that section but I managed to stay upright even if it wasn't that pretty.

Speaking of racing, the short travel setting feels decidedly 'racier,' which is to be expected, but I wouldn't describe it as harsh or less capable (remember, I accidentally did the whole Breck Epic in that setting). I just preferred the ride feeling of the longer travel setting, which was no less responsive but felt more fun and playful. Pivot says the bike is optimized for the longer travel setting, so if this were my bike I’d set it there and forget it, as I imagine most riders will do. I didn’t find there to be any disadvantage climbing in the longer travel setting, and it made for a much more pleasant descending experience.


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Mach 4 SL
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Orbea Oiz


How does it compare?

The Mach 4 SL isn't the lightest weight XC race bike out there — the small frame with DPS shock weighs in at 1930 grams — but that's likely due to the DW-link suspension design, which I think is worth the extra padding. This version of the Mach 4 SL is lighter than previous iterations of the same bike.

Even though the dw-link adds a bit of weight, it's ultimately what sets the Mach 4 SL apart from other bikes in the category. While the Orbea Oiz might have a bit more giddyup out of the gate due its low initial leverage ratio combined with relatively high anti-squat, the Mach 4 SL isn't exactly a slow starter. Plus, once it gets going, the suspension delivers a responsive and compliant throughout the ride.

Geometry-wise, the Mach 4 SL bears some similarities to bikes like the Oiz but they're not identical. Head angles and chainstay length are nearly the same at around 67 degrees and 432mm. However, the Mach 4 SL has a significantly slacker seat angle and a shorter reach when it's equipped with a 120mm fork.


Which Model is the Best Value?

The bike comes in four build options — World Cup, Team, Pro, and Ride. Pivot doesn’t downspec their carbon across the different builds, so each has the same high-quality carbon frame. Those build options are listed in descending order of price, with the World Cup — available in Shimano XTR and SRAM XX — both the most lightweight and expensive. That’s the model built around a Fox 32 fork with 100mm of travel and a Float DPS shock that switches between 93 and 105mm travel.

The Team build is essentially the same as the World Cup but with longer travel and Fox Factory Float rear suspension that flips between 103 or 115mm of travel.

Pivot says the Pro level is the most popular option. Pro comes with either Shimano XT/XTR or SRAM X0 drivetrains, and riders have the option to upgrade DT Swiss X1900 alloy wheels to the same Reynolds Blacklabel carbon that come on the World Cup and Team builds.

The lowest cost Ride build is offered in Shimano SLX/XT and SRAM GX/X01 with Fox Performance series suspension. The bike comes specc’ed with DT Swiss X1900 alloy wheels; no upgrades are available.

Prices range from the Shimano Ride build at $6,199 USD to the top tier Team XX Eagle Transmission at $11,599; needless to say, there's not exactly a 'budget' priced option.


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Technical Report

TwistLoc remote grips: I wasn’t a huge fan of the TwistLoc grip. I had to position the brake lever further inboard than I wanted to because the TwistLoc is fairly wide. And while I did use it occasionally on smooth dirt roads or pavement, I don’t know that I would miss it if it wasn’t there. It is nice to be able to control the rear suspension at the grip — I did occasionally lock it out on long dirt road climbs — but the bike pedals so well you can really ride with the rear shock wide open all the time.

Maxxis Rekon Race tires: I found the dual-Rekon Race combo a little too puny for most riding. I put a Rekon on the front for the Breck Epic and then swapped the rear Rekon Race for an Ikon after I tore a sidewall riding from Silverton to Telluride. Unless they're riding very benign surfaces (or solely focused on racing), I think most people will opt to swap the tires out for something with a bit more traction and control.




Pros

+ Efficient pedaling without sacrificing traction
+ Very comfortable for an XC bike - it's well suited to long rides & races

Cons

- 120mm fork configuration results in fairly short reach, which could make sizing a little trickier
- Not the lightest option, especially when compared to bikes with flex-stay suspension designs.



Pinkbike's Take

bigquotesI am obviously not a World Cup racer, but I believe I have some of the same priorities when it comes to an XC mountain bike — I spend a lot of time climbing and want something light and efficient. That said, I don’t want to be forced to be cautious while descending. The Pivot Mach 4 SL did not let me down in either scenario, and I tackled relentless climbs and technical descents with the same degree of ease — and had a lot of fun doing it Betsy Welch







Author Info:
betsywelch avatar

Member since Jul 30, 2018
15 articles

81 Comments
  • 25 1
 I own this bike, in the Team XT/XTR build and unlike a lot of current new XC rigs, the geometry is the limiter, not the suspension. First time owning a DW link and it's wildly effective but I wish they had designed the geo around a 120 fork with the option to put a 130 grip 2 on it for races like Downieville because the rear end is just that capable, I run out of stability on rough tracks long before the suspension is being overly taxed. I had the new Element last year and that bike was definitely more capable but the geo let you ride at speeds where you hit the limit of the suspension pretty quick (assuming you had more aggressive tires on it).

I can't wait to put some normal bars and a Dissector/Rekon on my Mach 4 this winter to test out the capability a bit more.
  • 6 3
 Why don't you just put a 120 fork on it? I did BC Bike Race on my V3 Tallboy and threw on a longer fork....worked great. I don't think you'd have an issue with a 130 fork....they say it works with a 120 fork.
  • 12 1
 @RadBartTaylor: I do have a 120 on it. They designed the geometry numbers (HA and Reach) around a 100 mm fork though so the 120 shortens the reach significantly. I think they could have gone more modern with the reach/wheelbase personally. Not extreme or anything but longer would suit the suspension better IMO
  • 5 0
 @briceps: Ah sorry - misread you comment.
  • 7 0
 Yep, agree that the geo is the limiter. That's why I got a Spur even though I'm a total Pivot fanboy.
  • 4 0
 @Mlloyd550: Spur seems pretty ideal for geo, still raceable unless you're at the sharpest end of XCO but long enough to rally. I would say my Element was almost too long but sure was fun just about everywhere outside of race courses.
  • 5 0
 @briceps: I was considering the SL, the tall boy, ripley, and yeti 115. Test rode them all and went for the transition Spur. For me it was funnier and felt faster. Not a racer but the spur with some upgraded wheels has allowed me to torch my PR on every non downhill trail I frequent. I love the way pivots and ibis ride with the DW link, but the spur was just funnier than anything else in its travel category. However, i think the SL is closer to a true XC bike then the Spur if someone is considering shaving seconds of an XC race
  • 4 0
 @NERyder: absolutely! I moved up to Cat 1 and really want to take a top 3 in our local series next year so the Mach 4 made more sense on paper. In reality with the same tires I'm not sure its much faster except when you're on a race course that requires lots of surges and attacks. When it's long steady climbs the differences are marginal between something like a Spur or Element and the Mach 4.
  • 7 0
 I think they really wanted to keep the reach a little shorter to keep it comfortable to pedal for long XC races. If you want more neutral geo with similar ultra fast pedaling capabilities, the trail 429 is a much better option.
  • 7 2
 Ever heard of a Trail 429?
  • 3 1
 @RWRides: I don’t think anyone here has heard of the 429. Enlighten us please.
  • 2 0
 @NERyder: " the spur with some upgraded wheels has allowed me to torch my PR on every non downhill trail I frequent." likewise. I'm running the Roval Control Carbon wheelset on mine (1,500g) with some fast tires, SID suspension, mix of GX and X01 and its faster than my outgoing Giant Anthem, despite having much slacker geo (66 degree head angle vs 67.5).
  • 2 0
 As longtime spur owner it’s the best bike ever owned. However, if you are into training and racing, a bike like this is what you want. It climbs better, no question. The spur is amazing, but the flex stay lacks traction. Pivot never intended for this bike to replace the 429 in it’s lineup.
  • 19 11
 As someone who's 6'7" I snickered a little. Slack ESTA, short rear end, really short reach and a little head tube. Yay it's like 1999 all over again. Enjoy your massive rearward weight bias and tons of headset spacers.
  • 5 3
 I’ve tested a few Pivots over the years. Can’t get past the feeling of sitting over the rear tire. The ETT always feels way too long for the relative size. But, to each their own.
  • 5 0
 Relatively shorter riders don't get as much weight over the rear with this kind of geo.
  • 23 0
 Am I oversimplifying by pointing out that, at 6'7"/201cm, any bike that has geo that works well for you is likely going to feel awkward for nearly everyone else in the world? I'd have to look it up, but my guess is that you're in the top 0.5% in terms of height globally. Seems similar to a 200kg guy lamenting that he can't get a perfect tune on his stock suspension... it's hard to please everyone, and nearly impossible to find a perfect stock setup for the extreme outliers.
  • 9 9
 @heyjohnp: Not if it's a frame that has size proportionate lengths and angles for each size. Sorry but Pivot is a bit behind or to be kinder caters to a more conservative rider with it's same size rear ends or very minutely changing rear ends like the Firebird. My opinion of course but I believe Pivot relies to much on the DW Link efficiency and has gotten lazy on size proportionate frames and is behind when considering that their pricing is on the boutique end of the scale.
  • 3 10
flag SunsPSD (Dec 18, 2023 at 10:27) (Below Threshold)
 @BermJunky: Yah, it's an amazing suspension design to ride but I've never felt as awkward on a bike as I do on a Pivot, like any Pivot.
This model seems to double down on those decisions.
LOL at the Spur comparisons though, I needed the laugh so that was nice.
  • 6 0
 @heatproofgenie: If an XL were built to fit this particular rider, it would likely feel bad for a 6'1" - 6'5" guy. Similarly, I'm 5'9"; if I rode a bike that was designed for someone 5'7" and below, I'd dislike the way it felt as well.
  • 3 0
 @heyjohnp: I'm with you. I just feel very few in the industry are getting each size proportion grow in the correct manner. Forbidden has it right though. Best example for how each size should grow IMO. Obviously Forbidden doesn't have something that is directly comparable to a Mach 4 but I believe the example still is worthy.
  • 2 3
 As someone taller than you, don't even pay attention to the brands that don't make adult-sized bikes. It's not worth the energy to hate on brands that can't be bothered.
  • 8 0
 I'm a simple man - I see no headset routing, I click buy
  • 7 0
 I absolutely love the design of the new M4SL.
  • 3 0
 Pivot price points are just absurd, $6200 for an entry level group is just silly. And they do not even offer a frame only option

Still the big plus is that they are showing that you can build a perfectly capable trail bike in the 25-27 pounds range. Keep everything the same and add 10 mm in the back and 20 in front and you have a real winner.
  • 2 0
 Ops! I take it back: they do offer a frame only option!
  • 1 0
 @Vyckinis: I just asked on the chat at Pivot and they said that they offer frame only for most models. YOu probably have to call a store and ask to purchase the frame.
  • 11 6
 As the word hasn’t been used and as a tribute to Levy I want to say that this looks like a perfect DOWNCOUNTRY bike.
  • 11 1
 Almost. The next up the Pivot line, The 429 Trail, is a bullseye on ‘DownCountry’
This is squarely a stout XC bike.
  • 2 0
 So i'm in the market for an XC bike and narrowed it down the the Ibis Exie and this. Of all things, it came down to better brake caliper clearance on this bike. There's a kink on the seat stay, which gives clearance for the chainstay mounted calipers. It's kinda silly to choose an XC bike based on what brakes it can use, but oh well.
  • 6 0
 you made the right choice anyways the mach 4 is better than the exie as someone that has ridden both.
  • 3 1
 I lusted after the original 26er top-spec Mach 4 and saved all my pennies. Got one slightly used for the then-ridiculous sum of $3000. First DW-Link bike and it was truly amazing coming off a single pivot bike. Rode it for years until I had to move to 29 to stay on trend. Couldn't afford the Mach 429 at about $6k then. Lusting after this one, but damn, $10k is just so far out of reach.
  • 2 0
 I have a fancy 429 and it seems like the Pivot Owners Group FB is just full of deals. I bet you can get the same bike in a reasonable price range if you hunt a bit.
  • 4 0
 Could drop some more weight pretty easily with 240s and lighter rims, too. The Reynolds are fairly heavy iirc
  • 4 3
 This is a really good bike, very versatile too. I rode with some high school racers earlier this year, in Marin, who had this bike. It could do everything my trail bike could ( ibis mojo 4) , with a lighter weight on the scale. Very much a downcountry competitor to the spur…
  • 4 0
 I recently got a Mach 4 sl World Cup xtr and it is exactly 23 pounds with pedals and bottle cages.
  • 1 0
 Does the flip chip only adjust travel? Since it wasn't mentioned, I'm assuming it doesn't change the geometry or kinematic significantly. In that case, why wouldn't you always want more travel given everything else is exactly the same? Set starting sag based on units (mm) instead of percentage, and it will even feel the same, with a little extra at the end.
  • 1 0
 Yeah the review isn’t clear (to me anyway). It says “ 95mm or 103mm on the World Cup builds, and 106mm or 115mm on all other builds”…the geo chart is for 100 vs 120 fork; I assume (?) the 120 build uses the 115 rear? And the 100 fork uses 106? Or is the WC build using different stroke too?
  • 1 0
 Realistically flip chips will always affect multiple settings. Even a flip chip that's just stated to alter geometry will change progression, anti-squat, or anti-rise. I'm sure that this flip chip adds travel and reduces progression so that you don't have to change spring rate on the shock, but you probably should since DW link is so sag-dependent with its performance.
  • 1 0
 @frorider2: the WC build uses a 190 x 40mm shock while all others use 190 x 45mm
  • 3 0
 The thought of a 6’7” human on that XL frame is just comical. Maybe 6’2” and that would still be pushing it.
  • 5 1
 Two water bottles inside the frame are a must for an XC bike nowadays.
  • 4 6
 Agree, the bottle placement plus the press fit rules it out for me.
  • 10 1
 @Snowytrail: it shouldn’t. I have add two Pivot frames and their BBs have all been less creaky* than my threaded BB frames.

* which is to say: absolutely no creaking whatsoever.
  • 3 0
 @pmhobson: I have had several pivots as well as a Kona with a PF92 BB and they were all creak and maintenance free
  • 2 0
 I haven't found a chainring that allows me to ride all of Wheeler Pass. Maybe one of those e-chainrings would do the trick
  • 3 0
 ...but the Epic Evo exists.
  • 1 0
 Having ridden the last version, if this one is like that, it can punch above its weight/perceived intent.

Hump
  • 1 0
 Looking at these new XC, I see that Niner was ahead of its time with the Air 9 alloy
  • 1 0
 Looks sweet, nice report! Is it actually able to hold 2 bottles?
  • 1 0
 Yeah, but the second one is under the top tube.
  • 1 1
 I was going to ask as well. I haven't been able to find pictures with 2 bottles in the front triangle. Can anyone confirm what size bottles fit in the M through XL frames? From all the pictures I've seen with one bottle on the downtube (granted I don't know which sizes they were on random Google search), there doesn't seem to be much room left under the top tube for a decent sized bottle.
  • 4 4
 Why can't they use millimeter in their geo chart. Using centimeters is just silly.
  • 29 7
 I know it’s tough, but if you move the decimal two positions to the right you’ll get the number you desire.
  • 13 0
 @BikesBoatsNJeeps: Isn't it one position to the right? Maths are hard for me, but I might be on to something here.
  • 19 0
 @BikesBoatsNJeeps: You've got the right idea, but it would work a lot better by only moving the decimal one place. Like you said, figuring these things out is tough. Smile
  • 12 2
 An American giving instruction about the metric system haha. So close!
  • 1 0
 Please tell me you raced in the cutoff denim! Sick look!
  • 1 0
 I have the older 2020 120mm Mach 4 SL, I absolutely love it.
  • 1 0
 160mm XTR brakes with their small Dura Ace pads don't suit the bike.
  • 5 5
 When do they release the men's colors? JK.. kinda..
  • 3 0
 They have the new one in a raw carbon look
  • 1 0
 I know I’m way behind on this comment but yea, Pivot probably has the shittiest paint jobs of any bike company ever. Bland as hell. I will say however that I do like the sea foam green. First pivot paint job even remotely appealing to me
  • 1 1
 Is barf-blue a color?
  • 2 3
 Looks like there’s a new “dentist” bike in town
  • 1 4
 like the bike. hate the shock position. It's great if you want bone-dry internals and shortened service intervals.
  • 1 0
 Idk man, it might be better this way. My deluxe ultimate is the other way round on my bike and it feel like it spits oil like that. Idk though
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