Originally Posted by
non-fixie
Thanks, Chas. I'm still trying to find the courage to mount those Grifos on another set of rims.
What happened is that under downhill braking the tire would shift ever so slightly on the rim, taking the inner tube with it. In the picture below you can actually see the rear valve stem already being askew (I'm sure I didn't mount it that way). It sheared off later that morning for the first time. Solutions that were suggested were a) glueing one side of the tire to the rim and b) applying a liberal dose of talc powder to the inner tube so it won't be dragged along with the tire.
Challenge Grifos are cyclocross tires made in both clincher and tubular versions.
The clinchers have folding Aramid beads. Folding bead tires can be very difficult to install on some rims. There's a possibility that they could fit too loose on other rims???
Here's a scenario... Say the Grifo tires fit loose on the rims they're mounted on. The knobby tread pattern can tend to grip the pavement unevenly - they can repeatedly grab and let go especially when braking hard downhill.
The tires get gradually pulled backwards causing the valve stem to pull backwards in the rim too putting stress on the tube???
Question... why do you run cyclocross tires? Off road ridding? Gravel grinding?
I stopped using knobbies on paved surfaces years ago because they're noisy and create a lot of vibrations that get transmitted into my hands, feet and other areas.
BTW, I use talc in all of my clinchers. It helps in preventing pinching during installation plus the tubes settle into the tires better. I keep my spare tubes in baggies with a little talc too.
Regardless of what Jobst Brandt had to say about talc covered tubes, it's been used in all types of pneumatic tires for over 100 years!
verktyg
Chas.