kcirick

I don't think I'm posting this in the right forum, but I don't know where to stick it, and this has to do with my road bike (or rather, bike that I use on the road), so here it is.

I'm a newbie when it comes to changing inner tubes, and while I know I'm doing things right, I can't be positive that I'm doing things effectively. three times in a row, I have my inner tube pop on me while the bike is just sitting there not being ridden (all I hear is all the sudden "pop... pfffffff....."). It could be a pinch, but I can't see myself pinching tires three times in a row.

Further investigation on this matter: my tire is rated at 700x28, and inner tubes that I've been using is rated up to 23 or 25. Does that matter? If I use the innertube that is not rated for 700x28, would this lead to premature puncture?

kcirick

Bump... Anyone?

I guess the main question I'm asking is the following:

rm -rf

Off the bike, you can blow up a bicycle tube to be 5 or 6 inches in diameter. They stretch a lot. Still, a tube sized 25-32 would be better than one sized 18-23.

Where is the hole? You need to match it up to the wheel to see if there's a sharp edge on the bike rim or the tape isn't covering the spoke holes completely.

If you were pinching the tube under the tire bead, it usually works it's way out from under the bead, blows up like a balloon, and pops with a loud BANG! And the tube would have a long tear down the side where it exploded.

Do you have a long tear or a smaller hole in the tube? Is the hole on the rim side or the tire side of the tube?

zonatandem

Been cycling since the early 1970s.
A narrower tube will fit easier than a wide one and works just fine.

kcirick

I checked both the tire and the rim, and I didn't find any sharp edges. The hole is a tear and it is on the rim side, i don't think it was near the bead. The last one I checked had a small tear in the position where the spokes connect, so rim recesses a little bit.

I don't know, I've tried changing tires probably 10 times, and success rate is about half it seems.

Yellowbeard

If the hole's on the rim side then it is near the beads. The size isn't the issue. If anything that should make a pinch less likely.

Are you actually checking to see if it's pinched after you mount the tire? If the hole is a jagged tear or a long split then that's probably what it is. After I mount a tire I start from the valve and go around the tire pushing it towards either side of the rim. If I can see the rim tape on each side I know the tube isn't pinched. I also push the valve in a bit to make sure the thick bit of rubber isn't trapped between the beads. Never had a tube blow out doing this.

Yellowbeard

Have you checked your tires for holes?

telebianchi

A few tube inflation things I do that may or may not help the specific issue, but since you are new to this I will share:

1) After putting the tube in and tire set, inflate tube about half way to lock the bead on the rim. Then deflate the tube and follow yellowbeard's instructions of pressing in the tires. Then inflate to full pressure.

2) Use talc or baby powder on the tube and inside of the tire. Some tubes come pre-talced but not all of them. The talc allows the tube to move inside the tire. Plus, when you're applying talc to the inside of the tire, you'll be running your fingers through it and can catch any thorns, sand, whatever that might have gotten inside of it. (Just bought a used bike for my girlfriend with 700x28 tires. Bike had barely been ridden so tires looked practically brand new. First time out, pffffsssffssfsttttt. Flat front tire. Checked it out and there was no talc; the tube was literally stuck to the inside of the tire as though it had been put in with double-sided tape. Nice rip in the tube right by the valve-stem. Checked the rear and same thing. Fixed both before the next ride.)

3) You know the little nut that goes on the valve stem? Don't tighten it too much and once the tube is inflated you can take it off. It's really only needed to keep from pushing the valve stem inside of the rim when inflating a tube with no air in it. (Back to gf's bike in point 2, the valve stem nut was tightened so hard on the rear that the tube was getting pulled through the valve stem hole. That's bad.)

joe_5700

With the tire mounted and no air in the tube, push the tire away from the rim and check to see that the tube is inside of the tire all the way around on both sides. You will often times notice some tube out of the tire right by the valve. Push the valve into the tire and this will solve most (if not all) of your pinch flat issues.

kcirick

Thanks for all the pointers and suggestions. I will do all of these checks the next time I'll change the tube.