- - Knolly Bikes Creates New MTB Rear Axle Length Standard

Knolly Bikes Creates New MTB Rear Axle Length Standard

As inveterate roadies, we mainly stick to the tarmac. However, when something as innovative as new rear axle length standard for the MTB segment emerges, we’re compelled to report upon it.

Such is the case with the Canadian bike brand Knolly Bikes, who have increased the rear axle spacing on their MTB models to 12x157mm – calling it 157Trail.

“We don’t buy into hype – we design bikes that have amazing ride qualities and our focus is on no-compromise high end product”, says Knolly’s CEO Noel Buckley.

According to Knolly, for the past few years they’ve witnessed larger forces in the bike industry push what they call advancements onto the market, but sometimes it is the smaller companies, the ones with engineers at the heart of them that create a product that offers something more substantial.   

“But before we go forward, let’s look back a few years. When Boost 148 was launched, we chose to remain on the sidelines because we were not convinced it was right. At Knolly our design philosophy demands that any performance feature change needs to be supported by a valid engineering position and proven rider performance benefits. And we think we were right to wait. Boost was designed to help fix a problem with 29er wheelsets and it was marketed as “a huge improvement in stiffness”. When in actual fact it was simply the widest possible hub width that could be implemented while maintaining normal Q-factors of existing 2 x 10 speed drivetrains and it was limited by certain suspension designs rear stays. Boost 148 was then adopted as a solution by the “plus size” tire community because it gave another 3mm of tire clearance per side. Unfortunately, it did not solve all the tire size issues, and it resulted in unfavorable geometry when switching between 27.5” and 29” tires”, explains Buckley.

“After creating a list of “must have” features to ensure our new line up of bikes can do everything we want, we decided that the only option is to move our entire lineup to the existing 12 x 157 rear spacing. We are calling it 157TRAIL because our Four by 4 suspension allows us to use the wide flange 157 hubs with 73mm BB shells on all our new trail models. The first models to launch will be the upcoming Fugitive 120mm travel 29er and Fugitive 135mm travel 29er. We made this choice because our design priorities are rooted in rider functionality, not in industry trends or marketing.”

Buckley adds, “we have significant experience running trailbike drivetrains on wide chain-lines. We don’t claim to be the first to bring this back to the market, but our “Trail” version of the 157 spacing allows us to achieve incredible design innovations in our new 2018 frames. We only incorporate design changes when there are legitimate benefits to the ride experience.”  “If the current wave of 1x drive-train technology existed, the wider spacing revolution would have skipped right over 148mm and landed on 157mm. By using 157TRAIL, our new bikes give consumers the widest range of features possible.”

So why 157?

TIRE SIZE: 157TRAIL allows us to eliminate tire width and focus on tire diameter. Riders can pick their wheel and tire combination based on intended purpose: be it a razor-sharp handling rocket ship, or a rock crawling monster truck (or anywhere between). Knolly’s Fugitive is built around 29” wheels but it can also run 27.5” x 3.0” wheels/tires without compromise to the BB height.

Q-FACTOR: 157mm hub spacing can be implemented using a flipped chain ring to maintain existing Q factors on XC / lightweight cranksets such as XTR, XO1 and Race Face Next SL.FRAME CLEARANCE: Knolly has re-designed the entire rear-end area to keep things as tight as possible. The 157TRAIL spacing increases rear axle width by 15mm (7.5mm per side), and yet heel clearance of our new designs has only moved outward by 1.5mm per side! Their new 157TRAIL rear-end remains the same or in some cases narrower than existing Boost 148 bikes currently on the market.

CHAINSTAY LENGTH: Due to their Four By 4 Linkage and forward mounted seat tube Knolly didn’t need to extend chainstay lengths to accommodate larger wheel sizes, including standard sized 29″ tires and high volume 27.5 Plus tires. Four By 4 also allows them to use 73mm bottom brackets shells and is front derailleur compatible.

CHAINRING SIZE: Chainring clearance remains huge: at 36T for 29″ models and 38T for 27.5″ models.

• Frame shown with 38 tooth front chainring. (36t max on the 29er)

• 2x drivetrains are still an option for those who don’t want to give up their front derailleur.

• E-type standard is maintained for easy mounting of upper chain guides.


• 29” wheels up to 2.6” tires.
• 27.5” wheels up to 3.2” tires.
• Adjustable geometry.
• Fits wide rims & wide tires (or narrow rims and narrow tires if that is how you roll).
• Multiple shock stroke length options on same frame.
• Front derailleur.
• 12mm axle compatible with existing and upcoming freehubs and cassettes.
• ISCG 05 Chainguide.
• 26t-36t chainring sizes.
• Threaded bottom bracket.
• LIFETIME warranty.
• Buy online and still support IBD’s
• Company does NOT make E-bikes.

Buckley concludes by saying, “we have a reputation for producing bikes that last and we are known for not jumping on the latest trends. We have thousands of loyal riders that, year after year, have ridden our brand because of the performance of our suspension, the longevity of the product and the customer service we provide. So when it came time to overhaul our entire model lineup, we knew we have to live up to the expectations of our riders. Our move to 157TRAIL enabled us to design, build and deliver the highest performing mountain bikes in the industry. Again.”

You can learn more about Knolly’s innovative design by visiting their website at


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