Troubles for road tubeless

21/10/25 18:59 Filed in: Gear

You can just about guarantee that motorbike, automobile and mountain bike tyres are tubeless without checking. But road bike tubeless is affected by trade-offs that might swing any given rider either way.
Clincher rims, rims made specifically for high-pressure tyres with tubes, are able to "clinch" because of the hook on the rim. Both sidewalls of the rim end in a small inwards facing bump - the hook. The tyre bead grabs onto the hook with the tube pushing outwards on the tyre - a safe and robust system. When you get a flat, the tyre can roll off the rim and cause a crash.
MTB rims have become tubeless because it makes the rim more robust and at the low pressures people should be running their MTB tyres at (<30 psi) they don't try to escape from the rim well. No hook can also give the fat tyre a better shape - Stan's rims use tiny hooks (left over from skinny rim days perhaps?) to avoid interfering with tyre shape.
Road rims, even with wide (for road) tyres on them, have to contend with lots of air pressure compared to MTB. A typical MTB tyre runs mid-20s. A typical tubeless road tyre runs 3 or 4 x that much (depending on tyre, rim and rider weight).
I run 18/24 psi in my MTB tyres (with foam inserts) and 70/75 psi in my one tubeless road bike.

Not many sealants will seal at 75 psi. None will seal at 100 psi. All of them seal well at 20 psi. That's the difference and the problem.

Michael Hanslip Coaching

If you want to go faster, you have to pedal harder

Troubles for road tubeless