Zaphod Beeblebrox 

I've had 3 tubes go flat on me in the last 7 days. All on the rear wheel of my Super Course.

When I inspect the tubes afterwards I see a tiny hole about 6 inches away from the valve along the part of the tube that sits on the rim strip. I've checked and re-checked my rim and rim strip and the inside of my tire (Hard Case Bontrager's) and I can't find anything even remotely spikey in there. No spokes sticking up through the nipple, no burrs along the spoke bed or on the sidewalls...

The only thing i've noticed is that if I park the bike with the rear tire valve at the 6 o'clock position, the tube goes flat. If I'm careful to park it with the valve at the 12 o'clock position it won't go flat.

any ideas?

I'm about to just bring the rear wheel to my LBS and say "fix it", but my ego is not yet ready to concede defeat.

USAZorro

Experiment. Reverse your rim strip direction, and see if the hole happens on the same side, or the other one. Also, mount your tire 180 around the rim from how you have been doing it. If you get a flat, you'll see where it is, and know whether it's the rim, strip, or tire.

prettyshady

Definitely experiment, I don't think a bike shop would spend much time on this problem.

Try differnt rim tape / electical tape?

Hydrated

Make sure that you park it with the valve stem at the 12 o'clock position. Problem solved.

That'll be $5 please...

roccobike

I had an almost identical experience. I kept flatting and blamed the low cost tubes that I bought. I changed the rim tape and bought a better brand of tube. The only difference was I went 18 miles before it flatted rather than 2 miles. After riding it that 18 miles, I found the tire had a small hole on the side that was pinching the tube with each revolution. It was barely visible when filled with air and NOT visible when deflated. Running my hands over the tire and inspecting it deflated did absolutely nothing because, even now that the hole is expanded, you can't see it deflated. USAZorro gave you some good advice. That should help to narrow it down.
Also, next time you inspect your tire, inspect it fully inflated, and look for small cracks including the sidewall.

Zaphod Beeblebrox 

Sorry, I just spent that 5 bux on a new tube

Thanks guys, I have a nagging suspicion that its some kind of pinch thats causing it...when I inspect the tube I see like a tiny little snake bike on the part that faces the spoke bed.


Should I be patching these flats or buying new tubes?

USAZorro

Might be installation/inflation technique. Try covering the rim strip with slightly wider masking tape. The other possibility is tire underinflation - which increases the risk of pinch flats.

leecycle

One technique that helps prevent pinch flats is to "talc" the inner tube before installation; that way as the tube is inflated, it is less likely to get stuck on the rim and get pinched.

Zaphod Beeblebrox 

cool thanks, I've done pretty much all of the above.

I checked the rim at the spot of the puncture and sanded down the edge of the spoke hole so it was totally smooth.
I replaced the rubber rim strip with Velox adhesive cloth tape
Put Gold Bond on the tube before installation.
Its inflated to 80 psi now and sitting happily...we'll see in the morning.

scozim 

"I replaced the rubber rim strip with Velox adhesive cloth tape"

I went through this problem 2 months ago and the above fixed it for me. The old rim tape was not adhesive and would shift when I put a tube in and mounted the tire. After a couple of weeks of flats after hitting deeper road cracks and then getting a subsequent flat I went with the Velox adhesive tape (and a little wider one) and there have been absolutely no problems. I suspect the tube was getting pinched on an exposed spoke hole.

Panthers007

Ad inflate the tube all the way to the shape it will be when fully inflated. Then push it up all the way into the tire and, with your fingers pushing upwards in the tire, mount the tube/tire onto the first side of the rim so the bead is seated. Now with your fingers again - work the other side of tire-bead up onto the rim. Keep working, through the tire from the outside, the tire and tube so you are sure it's not getting pinched. As best you can.

Then I suggest inflating your tire about 1/2 way - and go away for an hour or two. Still holding? Continue inflating to your usual pressure. Go away again. Still holding? Good! Pat yourself on the back and go for a ride!

jamesl

If you haven't already, swap tires front and rear and see if the problem moves. I second the comment on the tiny, basically invisible slit in the tire sidewall. I had that happen to me and it was a major PITA.