Hi I have a repeat problem with blowing tubes. I am using the 55 gram Vittoria tubes and recently I have started having problems with blowing the tubes on the front wheel. The tubes always blow a hole near the valve stem. Around the valve stem on these tubes is an extra thick layer of rubber. The hole always appears on the join between this thick layer and the thiner layer of the rest of the tube.

The hole is always on the side of the tube facing the rim. The rim has no abrasions nicks etc.

I use Talcum powder on the tubes when I fit them. My local bike shop says they have only ever seen this problem with these tubes and the early Ksyrium rims I am using.

The tubes will sometime blow in the middle of the night or as in the weekend while I was riding along a flat smooth road. I pump my tires up to 110 lbs.

I am at a loss to understand why this should be so and what is causing the problem.

Any thoughts or suggestions would be appreciated on what is causing the problem and what I can do to stop the problem recurring would be appreciated.

Can you help.

They're rubbing on the inside of the rim/valve hole. Put a 6" piece of Velox rim tape at the valve hole and the problem will stop.

Thanks for the response. Have you experienced this problem before?

Because the hole in the tube was about an inch away from the rim/valve hole I had assumed that it couldn't be the hole itself that was wearing the tyre. I had a kind of hazy idea that it might have something to do with the valve holding the tube motionless at a single point and then the tube being repeatedly stretched close to this with braking forces?

I had this problem with an earlier set of Kysrium Elites. For whatever reason, the outer valve hole is the diameter of the presta stem, while the inside hole is large enough to fit a schrader valve stem. The inside of the larger hole was left a little rough in the milling process and repeatedly abraded holes around the valves of my tubes. I solved the issue with three layers of electrical tape with presta-sized holes cut through with an exacto knife. The cushioning of the three pieces of tape seemed to work.

Thanks guys for the excellent help. Yep the valve hole on mine was larger on the inside as well.

I have applied the tape as suggested (I used some of the Vittoria self adhesive cloth rim tape - very similar to the velox stuff recommended.). I've had experience with the edges of electrical type tapes cutting tubes before, so elected to use a cloth tape.

backinthesaddle and rcordray many thanks for the answer. Much appreciated.

I had 2 Michelin A1 with the same problem and 1 other brand
I had to put the tube under water to see were the leak was, and very small air bubbles
came out.
With a magnifier i could not see the hole, but it was right at the junction of the valve rubber
and the tube.
I guess the lighter the tube the thinner the wall must be and joining the the heavy valve rubber to the thin tube rubber must be more critical.
Here is a pic of were the holes were (not on this mich. tube)

I had 2 Michelin A1 with the same problem and 1 other brand
I had to put the tube under water to see were the leak was, and very small air bubbles
came out.
With a magnifier i could not see the hole, but it was right at the junction of the valve rubber
and the tube.
I guess the lighter the tube the thinner the wall must be and joining the the heavy valve rubber to the thin tube rubber must be more critical.
Here is a pic of were the holes were (not on this mich. tube)


Nope, it's the wheel...:thumbsup: