Knolly Bikes has announced it’s building all of its frames with 12x157mm rear axle spacing, which it’s calling ‘157Trail’.
Before the pitchfork-wielding masses come out, it’s worth noting this is not a completely new rear axle standard. Pivot’s Switchblade uses a 157mm “SuperBoost” rear axle. Long before that, 157x12mm rear axles were used on freeride and downhill bikes, although the flange spacing of these 157mm hubs was narrower.
Knolly CEO Noel Buckley explains the decision by saying: “We only incorporate design changes when there are legitimate benefits to the ride experience. If the current wave of 1x drivetrain technology existed, the wider spacing revolution would have skipped right over 148mm and landed on 157mm.”
- Dear bike industry: really, a ‘new’ 20x110mm axle standard?!?!
- A guide to mountain bike axle standards
- What ‘standard’ really, really grinds your 8/9/10/11spd gears?
Knolly 157Trail highlights
- Fits wide rims and wide tires
- Front derailleur compatible
- 12mm axle compatible with existing and upcoming freehubs and cassettes
- ISCG-05 chainguide compatible
- 26t-36t chainring sizes
- Fits up to 29 x 2.6in and 27.5 x 3.2in tires
Q-factor isn’t a mile wide
Knolly states that its frames can run most cranks, including those with the narrowest Q-factor of 168mm. The trick is flipping the chainring so the ring pushes the chain line out an additional 6.5mm to 57.5mm.
Stiffness and tire clearance
Knolly claims the move to 157mm rear axle spacing results in a nearly threefold increase in lateral wheel stiffness.
Mega tire clearance, up to 3.2in for 27.5in wheels and 2.6in for 29in wheels, is another claimed benefit.
This one hits home for any rider with big feet; there’s a reason a lot of chainstays have the paint rubbed off. Knolly contends that its new 157Trail rear end is narrower than some 148 Boost rear ends.
A lot stays the same
Knolly claims that its chainstay length will stay the same, as will its use of threaded 73mm bottom brackets. Chainrings up to 36t can be run, front derailleurs can be fitted, and any ISCG-05 chainguide is fair game.
The first bikes to implement the 157Trail rear axle spacing will be the Fugitive 120mm and 135mm travel 29ers.