flats without punctures?

[nishiki1]

Hello,

I just bought a '92 xt and on the 8 hour ride home I had two flat tires on the rear wheel. After the first flat, I checked the tire and found no nails/thorns/etc. I had the tire patched (using spare rubber from another tube and rubber cement, TZ style)and remounted everything and filled the tire up to 26psi. Oh, I also ran my hand along the inside of the tire to make sure there were no abrasions; there were none. Four hours later I got another flat. After taking off the tire I saw that a: there was a brand new hole, and b: the original patch had started leaking. There were no nails or thorns in the tire. I have maybe 15kg of luggage and am driving over pretty decent tarmac at 110-120kph.

Why is the tube getting holes? What can I do to prevent this? Keep in mind my nearest access to tubes and tires is several hours away.

Thanks,

Brian

[This message has been edited by nishiki1 (edited 07 October 2004).]

[Laromonster]

could it be one of your spokes is protruding a little bit into the rim ? it could happen if you have adjusted/tensioned the spokes a few times. easily corrected with a file or coarse sandpaper, just remember to install a new whatchamacallit rubber band or even better a few turns with duct tape over the spoke nipples.
Another thing could be some nicks or gauges inside the rim from a tire iron mishap.
The third thing could just be a bad (or old )tube, i replace my tubes every second tirechange just as a precaution
*Lar*

[nishiki1]

Lar,

I will try the duct tape idea, thanks. Unfortunately I don't think that is the problem. All of the holes have occured on the outside edge of the tube (i.e., away from rim). As soon as I get my hands on some tubes, I'll be ready to change that tube out. I just don't want to be putting holes in perfectly good tubes if I can't fix the problem correctly.

Thanks for the advice.

Brian

[DougieB]

could it be similar to pinch flats that you get cycling/mountain biking? normally when you go over some rough stuff, or the tyre isn't properly inflated, the tyre can squash and the tube gets trapped between tyre and rim (the outside edge) and it punctures.

check pressure you're inflating to, is it correct? Is the tyre ok, or is it collapsing at the side wall?

[nishiki1]

The rear tire was properly inflated to 28psi and I was cruising with a moderate load on asphalt. Really no pinching should have ocurred. I just changed out the old tube for a brand new (but cheap quality) tube. Rode the bike today for 3 hours under similar conditions and no problems. I did however bump the pressure up to 35psi, which seems a little extreme. It rode fine, though. Unfortunately I have to replace the tires anyway. They were original equipment on the bike from 1992 and while doing all of this tube work I noticed some cracking. So long as I can make it home with minimal flats. At least it's not the front tire!

[This message has been edited by nishiki1 (edited 09 October 2004).]