Technical FAQ: Feedback on ‘pulsating’ tubular tires

Why does my tubular tire thump near the valve stem? - Feedback

Feedback on pulsating tubular tire wheels.

Dear Lennard,
After reading the letter from Rich to Lennard, we would be more inclined to offer instruction on re-gluing and re-mounting the tire.

The fact that he pointed out a noticeable raised section of tire, directly over the valve area, in combination with the fact that he admitted that this was maiden voyage with gluing tubular tires, leads us to believe that the tire is not actually adhered to the tire bed surface in this area, and causing the bump as he rolls over it on each rotation.

If he were to merely add some rotating counterweight to the opposite surface of the rim, he will most likely still feel the hop at downhill speeds, and associate it with an out of balance situation, which he will chase around in futility. There is always the off-chance that this is an anomaly which was not molded correctly, and truly may require some sort of counterweight, but in our experience this is less than 0.1-percent occurrence on standard production 404s.
Andy Paskins
Zipp Speed Weaponry Marketing Manager