Mountain Biking - New Rynolite Rims ripping thorn resistant shraders

I have new Rynolite rims teamed with XT hubs. Previously I have used Thorn Resistant Tires (Pyramid/Kenda) that are rates up to 2.25" tires. And I have been using Panaracer Cinders in the 2.25" width.

Now with my new rims, the inner tubes seem to be "slipping" inside the tires. These eventually rips the valve stems. This tire/tube combination worked fine on narrower rims. The bead on the Cinder's were a loose on the older rims, but you definitely need the levers to get them on the Rynolites.

The kicker here is that my "backup" tubes that are thin skinned do not suffer from the slippage and valve rips.

I know that the Cinder's are supposedly a little "large" for their rated size of 2.25". Will a switch to full blown downhill tubes (2.25-2.5 like the IRC Torque Tubes) solve my problems??

What pressure are you running the Pyramids?

What pressure are you running the Pyramids?

About 50 psi on the rear, 45 psi on the front.

My new theory on this is that the Rynos have a flat profile that doesn't mesh well with the rim. They are also wider and that effectively increases the internal volume of the tire. So the tube is slipping because it doesn't have enough contact with the rim.

I suppose the best of both worlds would be to find a 2.25-2.5" presta downhill tube. I REALLY don't like changing flats.

About 50 psi on the rear, 45 psi on the front.

My new theory on this is that the Rynos have a flat profile that doesn't mesh well with the rim. They are also wider and that effectively increases the internal volume of the tire. So the tube is slipping because it doesn't have enough contact with the rim.

I suppose the best of both worlds would be to find a 2.25-2.5" presta downhill tube. I REALLY don't like changing flats.
That's really odd. I'm running standard tubes on my Rhyno's with a 2.1 and haven't had those issues. Did you talc the tube when you installed it? That would allow the tire and tube to act independantly, but at those pressures it shouldn't be an issue. I've noticed that Pyramid Thorn resistants typically don't have much of a coating. Another thing to consider would be running Continental schraeder tubes (they have a lock washer like a presta) with a tuffy strip

That's really odd. I'm running standard tubes on my Rhyno's with a 2.1 and haven't had those issues. Did you talc the tube when you installed it? That would allow the tire and tube to act independantly, but at those pressures it shouldn't be an issue. I've noticed that Pyramid Thorn resistants typically don't have much of a coating. Another thing to consider would be running Continental schraeder tubes (they have a lock washer like a presta) with a tuffy strip

The standard tubes I run (after my thorn resistants blow) have not had this problem. A wiser man would simply accept the use of cheaper, standard tires. But I've had too much trouble with flats on trails before I switched to thick tubes. I'm pretty certain I'll eventually start having problems with this again.

Well, I suppose that the tire may be torqueing the tube and talcing the tube may help keep in place. I do kinda like the idea of everything staying together.

I have a pair of slimed prestas on order. And I'll probably order some IRC downhill tubes at my next opportunity. Hopefully one or the other will take care of the problem.