Bikes with a high main pivot and an idler pulley have had success throughout the years, but have never truly broken into the mainstream.
We're used to seeing FSR, VPP, traditional single pivot, and DW link configurations on the podium, with high pivot bikes not consistently featuring at the pointy end of the world cup downhill pack. But, recently there's been a resurgence of the design.
The bike of the moment is the Commencal Supreme that, under a young and relatively unknown Amaury Pierron, has won the last two World Cup rounds. There's also Myriam Nicole, who has taken a 1st and two 2nd placings in 2018, along with first-year junior, and another Frenchie, Thibaut Daprela netting the same results. So the high pivot Supreme is the most successful bike this year so far, leading elite men, elite women, and second overall for the junior men on the World Cup circuit.
What is a high pivot bike, and why?
Is it just rider talent, some luck, and good team management on Commencal's part? Or are we seeing a truly faster suspension system reemerge?
Adding to the high main pivot hype, Norco recently released their Aurum HSP
(High Single Pivot) bike with an idler pulley, and Sam Blenkinsop has since had some great results. Reportedly, after riding George Brannigan's Commencal a few years ago, Blenki wanted something similar to race on. This kicked off some experimenting
with an idler pulley attached to the standard Aurum to tune the bike's anti-squat characteristics, and after a year of prototyping and relentless spy shots, the Aurum HSP is here.
Most suspension bikes have their main pivot located somewhere around the top of the chainring, including many linkage bikes that have a virtual main pivot passes through a similar place near the top of the chainring.
Depending on the exact placement of the pivots and links, this could mean that a bike performs relatively neutrally when pedaling, braking, and hitting bumps. This is generally the preference for many companies, as it allows designers to tune kinematics for predictable, inoffensive, all around performance.
High pivot bikes have a physical pivot, or instant center, much higher than the top of the chainring.
A high pivot can create a rearward path at the axle, which, in theory, allows the rear wheel to more easily move away from, and then over, an obstacle. The high pivot position, however, leads to a lot of chain growth as the axle moves away from the chainring, which will cause a lot of pedal kickback. This is when the cassette sprockets move away from the chainring and the cranks are pulled backward as the chain is put under tension, a trait that can keep the suspension from doing its job freely.
But there is a solution - the simple addition of an idler pulley close to the pivot point that routes the chain up and over it. High pivot bikes equipped with idlers have characteristics that are unique: the lack of chain growth, along with the rearward axle path, allows the wheel to float over bumps in a very different way than other designs. The downsides can be poor pedaling performance, extra drivetrain complication, and high anti-rise values that essentially pull the suspension down into the travel and affect the sensitivity of the suspension. This anti-rise, in particular, is a love-hate characteristic. Some moan about it locking out the suspension, but generally I prefer the way it conserves the geometry of the bike when braking on steep downhills - this negative can also be 'out ridden' in certain ways, which I will get to in a future article.
High main pivot designs can, in fact, tune the characteristics of anti-squat, anti-rise, etc., by changing the location of the idler. Commencal has been seen playing with this at recent World Cups races by lowering the idler below the main pivot
, a change that would provide more anti-squat (and also more pedal kickback).High pivot history
So, Commencal has the bike of the moment, but the theory is nothing new. Let's take a look back over the last twenty years to see the movers and the shakers in the high pivot world.
VProcess / 2000
- This version of the V-Process bike had a high single pivot and idler. Oliver Bossard (bottom left) of BOS fame and Nico Vouilloz developed a new bike each year that was focused on winning on the World Championship track; the other events didn't matter as much to them. Sierra Nevada was fast and loose but had a lot of pedaling as seen in this video.
Coincidentally, 2000 was the only year Nico didn't win World Champs (he flatted) between 1995 and 2002, before retiring.
Balfa BB7 / 2004 - The BB7 was between a young Danny Hart's legs as his career kickstarted and he went on to win tons of races around the world. Some versions had a floating brake arm to neutralize the anti-rise of the high pivot. It had a chunky aluminum front-end for rigidity, but a steel rear-end was employed for added compliance and reliability.
Brooklyn Machine Works / 2005 - I have next to no idea what Brooklyn Machine Works actually did when it comes to model names, travel numbers or any stats. What I do know, however, is that they did a lot of mental shit, used a load of chains, loads of steel, and they all weighed loads, too. People loved them, and somehow Pharrell Williams of N.E.R.D was involved.
Trek Session 10 / 2006 - Trek's mid-aughts behemoth looked nothing like the Session we know today. Both it and its predecessor the Diesel used a single pivot layout with an idler. What a beast.
Empire AP-1 / 2008
- The Empire was radically different when it was launched. Its cast aluminum frame employed a high pivot with an idler pulley that was on the line of the chain towards the main pivot. It was also bloody heavy, and a couple of frames snapped in half under Alex Evans, regardless of the heft. Alex, who was racing internationally and helped develop the bike, is now our European Content Manager, and also raced a Balfa prior to the Empire.
Empire still sells the VX8 version of this bike today, but the cast metal approach has been replaced with a mixture of machined components and tubes.
Honda RN01 / 2008 - The Honda RN01 was a beauty to behold and the most mythical beast to ever grace a World Cup downhill track. Honda coming to the World Cup series was a serious deal. Its secret gearbox system turned out to be a derailleur inside a box when it was shown to the public, although I never quite believed that's all it was as Honda have some interesting patents that could have been hidden in there as well. It was a high pivot machine that had the chain running over the pivot after it was turned by the gearbox. Supposedly, there are only two left in existence after they were all crushed; one at Honda in Japan, one in Greg Minnaar's shop museum, and possibly another bike (sans gearbox) that was stolen from a race. The engineers used to split the gearbox from the bike and take it to their hotel rooms overnight!
Lahar / 2007 - The Kiwi-made Lahar must be the wackiest of wacky. Its carbon, single-tubed front-end starts the wackiness, and that's followed by a high pivot with a floating brake arm, two chains, and an internal gearbox. I remember Cam Cole racing this bike at the legendarily loose and dusty Montgenevre Maxxis Cup in 2006. At the time, it was silent compared to the rest of the rigs we had back then. After this, he took the bike home and piloted it to Junior World Championship gold on home soil in Rotorua.
2Stage / 2008 - This one isn't quite a pure high pivot bike, but it's too good to not include. The Kiwi's have a lot of explaining to do - so many weird bikes from such a small country. The 2Stage had it all: Idler wheel, floating brake arm and, not one, but two shocks. Nathan Rankin and Glenn Haden were racing in Europe on them over a decade ago.
K9ine Engineering / 2008 - The K9ine bike seemed to disappear as fast as it arrived. It had a steel front end and alloy rear, the opposite of the Balfa. Long dual links, an idler pulley, and a serious amount of Formula One-style testing and data acquisition went into this bike designed by Luis Arraiz, who now works at GT. This bike was also ridden and raced by James Mcknight, the man behind the Hurly Burly books.
Canfield Jedi / present - The Jedi is still available on Canfield's webshop in limited options for a crazy discounted $1099 USD for a frameset. The 'Formula 1' suspension design uses dual links and a one-piece swingarm, with the idler located in between the two links. I have never even seen one in the flesh, but have heard nothing but rave reviews from rare owners. This bike has a full 228mm of travel, as well as 90mm of rearward travel.
SuperCo Silencer / 2009 - The SuperCo Silencer used a high pivot and two chains. One chain from the crankset (steel, Profile BMX cranks, of course) to the idler wheel, which was on an axle that transferred the drive to the opposite side of the frame. The second chain went from the auxiliary idler to the derailleur and cassette. It also had a floating brake arm, which could neutralize the anti-rise effects of the high pivot.
Zerode G1/2 / 2011-15 - Zerode went one step further and integrated a Shimano Alfine internally geared hub into the G2 frame, just below the main pivot. This was another bike with two chains and a pivot that was seriously far above and behind the bottom bracket. Anybody that rode one seemed to love it. Zerode where also spotted prototyping a similar high pivot trail bike, which was superseded by the more traditional Pinion-driven Taniwha and, unfortunately, any trace of the G2 and the science behind it has disappeared from their website.
Ghost DH 9000 / 2013-2015 - This 2013 Ghost 9000 takes a more traditional 'looks like a Session' four-bar linkage and adds an idler pulley to tune the anti-squat and pedal kickback. The four-bar linkage is probably the most popular suspension layout in modern mountain biking because all the characteristics of the kinematics can be adjusted easily. This meant Ghost could tune the rearward axle path, but also manipulate the anti-rise and leverage ratio easily.
Redalp / 2012 - present - The Redalp gets a real hard time in the PB comments for being an ugly duckling, and rightfully so. But, it surely boasts the highest pivot ever? The idler is located on a linkage that moves as the bike cycles through the travel. There is another link to drive the shock, too, which is placed super high – presumably to tune the ratio, isolate the shock, and make it look even weirder.
Bulls Wildcore / 2015
- Wyn Masters was previously sponsored by Bulls, so maybe it was him who longed for that high pivot lifestyle and commanded GT to make him the prototype he's been racing on
this year. Or maybe it is because Luis Arraiz, formerly of K9ine, is now an engineer at GT. The Bulls bike had a high single pivot, and it used an idler pulley and a brake attached to the swingarm, which would make the bike squat under braking. The lower link, which almost looks like a mini-chainstay, is similar to the way the Commencal and Norco connect the swingarm to the shock.
The new school?
Bergamont e-Trailster / 2016- present - Well it wouldn't be an article by me if I didn't throw in an eMTB somewhere. The Bergamont still has one of my favourite suspension systems on an eMTB, and I thought we would see more designs like this, but it turns out that Haibike have a patent for high pivot idlers on e-bikes and they are featured on many machines in their range.
Within the last two years, there have been a number of other bikes pop up. Don't call it a comeback as they never went away, but many of these designs are generally from the niche, shed engineers, and the weird or short-lived marques. It is interesting to see Commencal, Norco, and apparently GT put some serious investment and confidence in these bikes, though.
The aesthetics of ARBR's Saker caused a hate storm when it was released, but I wonder what it rides like.
Peregrine Bikes from the USA make steel, Pinion driven, HSP downhill and freeride bikes.
Deviate Cycles have combined a Pinion gearbox with a high pivot system.
Holy moly, the Antidote DarkMatter is a beauty. The brake is located on the chainstay to reduce the anti-rise effect.
More niche and weird stuff from the UK. Starling has developed a single-speed bike that's a throwback to the Brooklyn days.
GT Prototype / 2020?
Sick Bicycles keep teasing with renderings of a 180mm-travel, 29" wheeled Pinion-driven bike.
- The GT sled has been seen at numerous races this year,
and we can only imagine it will be sent into production. Remember that Ghost from 2013? I thought it looked familiar. Also, the K9ine was an interesting bike designed by Luis Arraiz, who now works at CSG, the parent company of GT.
It will be interesting to see how these bikes are accepted in the future. Most of the machines from the past that are featured here died off for one reason or another, be it they were niche racing rigs, brands that couldn't manage themselves, or simply unappealing bikes that were a hard sell to fickle consumers. The biggest cull of these bikes was likely due to wheel size and standards changing so fast that small brands couldn't afford to keep up. Ironically, if win-on-Sunday-sell-on-Monday still holds true, the 29" wheeled Commencal and Norco could be some of the best selling downhill bikes of 2018.
Initial impressions of the Commencal has been extremely positive, and the Norco has just landed for testing. Both bikes are going head to head against some other 29" downhill bikes over the next few months, so expect the reviews to start landing soon.
What weird and wonderful high pivot bikes did we miss from the past? Let us know in the comments.