High Pivot MTB: The Pros & Cons of High Pivot Mountain Bikes

What is a high-pivot mountain bike?

Most full-suspension bikes, such as four-bar or single-pivot designs, place the main pivot somewhere near the top of the chainring. This applies to much-loved bikes that have a virtual pivot point as well, like the VPP and DW-Link. The difference with a high-pivot bike is that the main pivot is positioned significantly higher than usual.

The placement of the main pivot and the other links within the suspension architecture determines important suspension kinematics like axle path, leverage ratio, pedal kickback, anti-squat, and anti-rise. Compared to a traditional suspension design, a high-pivot results in a more rearward axle path and reduced pedal kickback.

Why did high-pivot suspension become popular (again)?

For me, and many who follow downhill racing, the high-pivot tipping point came during the 2019 World Cup downhill season. That year, a then-relatively unknown French rider, Amaury Pierron, shocked everyone by winning three World Cups in a row as well as the overall title. The bike he rode was the new Commencal Supreme, a 29" DH bike which used high-pivot suspension.

In fact, the entire Commencal team did very well that season too. Soon, other teams were scrambling to develop their own high-pivot designs, like the Norco Aurum HSP, GT Fury, and Trek Session. The Supreme has continued to win races, as has the latest high-pivot Session.

Whereas old high-pivot designs were really only used on downhill bikes, the rise of 29" drivetrains has given designers space to add high pivots to more consumer-oriented trail bikes. The Forbidden Druid (and later the Dreadnought) and the Deviate Highlander have been leading the charge, and now bikes like the Norco Shore, GT Force, and Cannondale Jekyll give riders more high-pivot options from major manufacturers.

High-pivot suspension doesn't work without an idler pulley

The key feature that makes a high-pivot bike recognizable is the addition of an idler pulley at or near the main pivot. You can't have a high pivot without an idler. The rearward axle path of a high-pivot bike causes a large amount of "chain growth" as the axle moves away from the chainring. This causes pedal kickback, where the cranks are violently pulled back as the suspension compresses. Not only does this feel unpleasant, but it prevents the suspension from moving freely and doing its job. The solution is to route the chain over an idler pulley that's close to the pivot. Placed correctly, this idler will greatly reduce or even eliminate chain growth and pedal kickback.

What are the advantages of high-pivot suspension?

To better understand high-pivot suspension, I got a lesson from Luis Arraiz, suspension guru and frame design engineer for Cannondale and GT. He's the brains behind the new Cannondale Jekyll and GT Force enduro bikes, as well as the GT Fury downhill bike. In the mid-'00s he actually ran a company called KGI Industries that specialized in high-pivot downhill bikes.

Rearward axle path

Because the main pivot is placed higher, the path the rear axle takes as the suspension compresses is more rearward than normal. It doesn't move rearward through the entire travel, just where it matters through the beginning and middle of the stroke. This rearward axle path is often touted as the party piece of a high-pivot design.

"Because the axle moves rearward as you ride forward, the wheel moves out of the way more easily and the suspension naturally absorbs impacts a lot better," Arraiz explained. "It doesn't get hung up on stuff so you float over rough terrain and carry more speed and momentum. Bumps don't slow you down as much. This is super beneficial in disciplines like downhill and enduro where the tracks are getting rougher and the speeds higher."

Reduced pedal kickback

"The main purpose of a bike with a high pivot and an idler has always been decoupling the drivetrain from the suspension action," Arraiz explained. "It makes a really big difference if you ride flat pedals. Pedal kickback is still a problem if you ride clipped in, but the high pivot will really benefit flat-pedal riders because the design reduces so much of the pedal feedback."

Pedal kickback occurs when chain growth causes the chain to pull on the cranks as the suspension compresses. Because the suspension is bound by your feet, it prevents it from moving freely. The rear end will feel harsher and at its worst it can bounce your feet off. But since a high pivot requires an idler pulley to control the excessive chain growth, it has the add-on benefit of eliminating kickback and making the suspension feel more supple.

Improved feel, predictability, and speed

There's another, more subjective benefit that Arraiz pointed out:

"The bike stays composed through impacts and keeps you feeling centered between both axles. Because both wheels move together toward the rear, the bike's wheelbase doesn't dramatically shorten. Combined with the bump absorption of the rearward axle path and reduced pedal feedback, it all adds up to improve the ride experience and the feel of the bike."

"If you have it set up properly, the bike is doing all the work and you can just concentrate on riding. You don't have to man-handle the bike, and you don't have to second guess what it's gonna do. It becomes very predictable, very easy to ride, and once you really know how the bike is going to react and you can just trust it and go faster. A good high pivot suspension design makes going fast easier and more effective."

Are there disadvantages of high-pivot suspension?

Weight and complexity

"The main disadvantage is extra weight and complexity. With a high-pivot design you have extra bolts, bearings, the idler, and a larger chain with extra links," explained Arraiz. "Also, there is about a 2% increase in drag. The idler also adds a little bit of noise too. I will say, sometimes the extra noise makes people think there's more drag than there actually is."

High-pivot designs also take some extra thought and tuning to perfect.

"In regards to designing bikes with rearward axle paths, let me say that you can have too much of a good thing," Arraiz warned. "If you have a bike that has too high of a pivot, it's going to have a very significant rearward axle path. That's great for a single bump. But when you're going through rock gardens you have repeated bumps. The force of the axle coming back forward into each repeated hit is significant and it won't feel as smooth as it should."

"You need to design something that's properly balanced. That's why bikes like the Jekyll, the Force, and the Fury are more of a 'mid-high pivot' bike, where you still get the rearward axle path, but enough that it feels smooth over repeated hits. You can't just slap a high pivot and idler on any bike and have it work."

Climbing performance

Of course, uphill manners matter to folks who tackle big climbs. Arraiz assured me that, other than the slight increase in weight and drag, properly designed high-pivots can pedal as efficiently as traditional designs.

"On the Jekyll and Force, we have about 95% anti-squat in the climbing gears," he explained. "They actually have a bit higher pedaling efficiency than the bikes they replace. Because we use a four-bar suspension with an idler, if given a lot more freedom because we can tune the anti-squat and anti-rise any way we want to."

It's also worth noting that with a high pivot and an idler, changing your chainring size won't change the anti-squat. With traditional suspension designs, going to a smaller chainring increases anti-squat while giving bigger ones reduces it. High pivots actually give riders a lot more freedom to pick the optimal chainring size for their needs.

Idler pulley maintenance

Some high-pivot early adopters have reported accelerated wear of the idler pulley, requiring frequent maintenance or even replacement. Because of its position on the drivetrain, a lot of pedaling force is transmitted into the single idler pulley.

"Well, those first-wearing idlers were probably aluminum," said Arraiz. "The main thing is that all our idlers are made out of steel to prevent excessive wear."

Most brands, like Forbidden, have switched to steel idler pulleys as well to reduce wear rates. Even made of steel though, an idler pulley won't last forever and will need to be replaced with other drivetrain components.

"We expect idlers to be changed when chainrings are changed, a cassette," said Arraiz. "I think that's a fairly acceptable wear rate."

Will we see high-pivot suspension on more bikes?

"On the enduro side of things, I think we'll definitely see more brands release high-pivot bikes," said Arraiz. "We already have a bike from Norco, and I think we'll see more bikes from Devinci and Trek soon too."