What causes a tear at the base of my valve?
A valve tear off can occur if it was installed under tension.
Another frequent cause is installing a Presta valve tube into a rim with a larger valve hole. The metal edge of the valve hole can shear the valve stem off the tube.
Caution: Be aware that there are also rims that have the correct valve hole of 6.5 mm on the outside, but a larger hole of 8.5 mm on the inside, which causes the problem. A nut that is excessively tightened just exacerbates the problem of tear off. The major role of the rim nut is to lock the valve in place at the time of inflation.
In most cases valve tear off is due to tire slip. Continual improvement in brake performance and low inflation pressures often cause the tire to slip on the rim. The tire movement then drags the tube and this can lead to the valve shearing off.
Another frequent cause is installing a Presta valve tube into a rim with a larger valve hole. The metal edge of the valve hole can shear the valve stem off the tube.
Caution: Be aware that there are also rims that have the correct valve hole of 6.5 mm on the outside, but a larger hole of 8.5 mm on the inside, which causes the problem. A nut that is excessively tightened just exacerbates the problem of tear off. The major role of the rim nut is to lock the valve in place at the time of inflation.
In most cases valve tear off is due to tire slip. Continual improvement in brake performance and low inflation pressures often cause the tire to slip on the rim. The tire movement then drags the tube and this can lead to the valve shearing off.
Updated on: 03/25/2025
Thank you!