Boost
The hub-width standard of most modern mountain bikes: 110 × 15 mm at the front and 148 × 12 mm at the rear. Wider hubs make stiffer wheels and leave more room for tyres.
Also known as: Boost 148, Boost 110, Boost spacing
Key facts
- Origin
- introduced by Trek and SRAM in 2015
What changed
- Front hubs went from 100 to 110 mm wide.
- Rear hubs went from 142 to 148 mm wide.
- The chainline moved out by 3 mm to match.
Why
Spreading the hub flanges wider makes the spokes brace the wheel at a better angle, so the same wheel is stiffer — which mattered as 29′′ wheels took over. It also gave frame designers room for wider tyres and shorter chainstays.
Compatibility
Boost and older non-Boost wheels do not swap between frames and forks. Some downhill bikes use a wider rear standard still: Super Boost, 157 mm.
Related articles
- SRAM — An American component maker from Chicago, founded in 1987. It made the 1x mountain drivetrain mainstream and owns RockShox, Zipp and Quarq.
- Trek — An American bike maker from Wisconsin, founded in 1976 in a barn in Waterloo. One of the largest bike brands in the world, with a full mountain range from hardtails to downhill.
- Drivetrain — Everything that turns your legs into forward motion: cranks, chainring, chain, cassette, derailleur and shifter. A modern mountain bike runs one chainring and twelve sprockets — 1×12.
- Suspension fork — The telescopic front fork that lets the front wheel move up over bumps instead of throwing them into your hands. It is what steers the bike through rough ground.
- Wheel size — Mountain bikes roll on 26′′, 27.5′′ or 29′′ wheels. Bigger wheels roll over obstacles more easily and carry speed; smaller ones are quicker to turn and throw around.