- Oversized drivetrain pulley wheels are popular on road bikes, but less so, on mountain bikes.
- They can make your drivetrain too vulnerable to damage, in very rocky terrain.
- Designers at a boutique component brand, think they have found the ideal upsizing option.
The diminishing return curve is a very real fact of physics and price, in mountain biking. If you want lighter components, or bits that spin with less resistance, they’ll cost a troubling amount of money.
Across the world there are engineers, industrial designers, fabricators and tinkerers who supply mountain bikers with a myriad of unique aftermarket components. If you want to add speed, or reduce effort, buying into the boutique parts culture is the gateway to going a little bit faster, by spending a lot of money.
The latest magic component to be revealed is from Texas. It is the work of Ard Kessels and his team at Kogel. As a Belgian, Ard’s technical literacy regarding all things bike is beyond reproach. After relocating to America, he has specialised in providing superior bearings for bottom brackets and derailleur pulley wheels.
For those mountain bikers who have already spent a lot of money on a lightweight carbon-fibre frame and wheels, the next place to seek marginal performance gains is reduced drivetrain friction.
Balancing risk and reward
You’ll often see road bikes with large derailleur pulley wheels, but it is a rarity on mountain bikes. One of the issues regards vulnerability, something road bikes aren’t exposed to.
Mountain bike drivetrain derailleurs can easily be knocked out of alignment, or completely destroyed, by rocks on the trail. Mounting a large derailleur cage with bigger pulley wheels, simply creates a bigger target for rocks when you are navigating a particularly technical and challenging trail.
Despite this, Ard’s team at Kogel has developed an oversized derailleur cage and pulley wheels, for SRAM’s very popular 1x12 mountain bike drivetrains. It replaces the factory 12- and 14t pulleys wheels with an arrangement that guides the chain around a 14- and 19t configuration. Kogel also adds its nitride ceramic bearings and the total claimed energy-saving, is 2.5W.
The theory with these larger derailleur cages and bigger pulley wheels is that any slackening of the chain is reduced, saving energy. This is especially useful when riding off-road, where rough terrain can jar the drivetrain.
Kogel’s oversized Kolossos mountain bike derailleur and pulley wheels will fit nearly all of SRAM’s 1x12 drivetrain systems: XX1 AXS (which is electronic), XX1, X01 and GX. The cost? R6000.