You’re railing that descent, nailing every line and feeling like a world champ, when suddenly you smash a wheel into a big square-edge rock. Quite literally, you can feel the air go out of the ride.

When it comes to portable bicycle tire-inflating devices, hand pumps require a lot of effort, while CO2 cartridges are single-use only. The aluminum Choka bike frame offers an alternative, by doubling ...