Like a modern automotive or motorcycle tire, tubeless tires and wheels may need to be submerged in water to detect a leak. A large sink, washtub or bucket will do, as only a portion of the wheel needs to submerged at a time. Inflate the tire to 50+psi, let the naturally trapped air escape from the rim cavity and look for a steady stream of air from the following locations:
Is there air escaping from:
- The tread?
UST: It is likely a puncture. Check for holes and objects in the tire.
Non-UST: It could be a puncture or in need of additional sealant. - The sidewall?
UST: This may be a bad tire. Occasionally UST tires have a sidewall that is too thin.
Non-UST: It could be a bad tire or in need of additional sealant. - The bead?
Check bead, rim, or seating. Also, are there any inspection stickers at the bead or rim? They must be removed. - Valve hole?
Check the valve. Is it too tight or too loose? Check it. You can switch it with a good or new valve to be sure. - Spoke hole?
This could be a seam or valve. Double-check the valve. - No Success?
Check with the manufacturer.
Notes:
- Tire irons may damage the bead of a UST tubeless tire and therefor these tires should be installed by hand.
- UST tires must be pumped to 60 psi to lock the bead in place.
- Sealants tend to dry or coagulate over time reducing their effectiveness. Stan’s suggests their sealant last between 2 and 6 months. Check the level of your tire sealant on a regular basis.
The information above was adapted from a file originally provided by Mavic USA.