We’ve been indulging our curiosity, finding out more about wheels, tyres and bikes: how they work and where they’re headed. We’ve been learning from Keith Bontrager, a motorcycle racer, frame builder and physics graduate, who turned his hand to making innovative bicycle components in the late 80s, before being snapped up by Trek in 1995.
With scrupulous attention to detail and an ability to think outside the box, he’s been pushing the envelope of bike design ever since, particularly in the interaction of wheels, tyres, and tubeless systems.
BikeRadar recently had the chance to sit down with him, nerd to nerd, over a coffee or two, hoping to draw on his vast knowledge and insights. We weren’t disappointed. These are a few of the things we learned:
1. Forget spoke tension – it’s all about the spoke angle
Keith Bontrager: Unless you loosen the spokes until they’re baggy, spoke tension has almost no effect on the lateral stiffness. Spoke bracing angle is the really big deal. When you add more gears, you create more dish; you’re also killing the lateral stiffness and stability of the wheel. When you push the driveside spokes inwards, it just makes the wheel that much harder to make.
Seb Stott: On a standard, non-Boost, rear wheel, the distance between the centre of the wheel and the drive-side flange is just 18mm. When you go to boost, that number increases to 21mm. How significant is that?
2. Wider rims are a no-brainer
3. Carbon wheels don’t have to be fragile
4. Symmetry is not important
5. Your wheels hold you up through a reduction in tension, not with tension itself
6. The bigger your tyres, the lower your pressures should be
You can read more at BikeRadar.com