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My tubes keep pinching , Is it the Rims?(7 posts)

My tubes keep pinching , Is it the Rims?Gdhan
Aug 16, 2001 12:45 PM
I recently bought a used bike with Rolf Vector rims. After a few rides the back tube pinch puntured two consecutive times. I went to my local bike shop and they said to add pressure,which sure enough, I was'nt getting from the gas station air pump.
We inflated to optimum pressure(120 psi), but the darn thing pinched on the following ride.
1) Are there special tubes for the Rolf Vector rims?
2) Is there any other advice you can offer that would remedy this problem?
3) Is it possible that the Road-Gods are against me because I just switched over from mountain biking?
Thanks for the help!!...
re: My tubes keep pinching , Is it the Rims?Tig
Aug 16, 2001 12:58 PM
1st, if you don't already have one buy a floor pump with a guage. Use it before every ride. Pump the rear tire up the the max limit printed on the sidewall. The front tire can be left a few psi lower unless you are a BIG rider. If you are big, you should be on 25 or wider tires. Unlike larger volume/lower pressure MTB tires, skinny road clinchers lose pressure fast.

2nd, remove your tire and tube and check the rim strip to see if it has slipped and exposed any nipple holes, etc. I have a set of the same wheels and had the problem for a while, but when I switched to some higher pressure Conti 3000's, the problem went away.

I'm sure I forgot something, but others can fill in the gaps.
All of the above, and...Cima Coppi
Aug 16, 2001 1:36 PM
Remove both tires and put baby powder on the tubes and the inner casing of the tire.

Also, once you have a floor pump, when you install a new tube, inflate it 3/4 of max pressure, then deflate it all the way. The re-inflate to max pressure. This usually ensures the tube does not get caught under the bead of the tire.

Good luck,

Beware some baby powders ...Humma Hah
Aug 16, 2001 5:19 PM
Only use talc. Some baby powders these days are corn starch, which makes a glue.

The supposed advantages of talc are a slight lubrication during assembly. There are those who dispute its usefulness. I personally have used it and believe I've seen benefits.
The Road-Gods probably have it in for you ...Humma Hah
Aug 16, 2001 5:17 PM
... Square edges you would not even think once about on a MTB can pinch a roadbike's tires. You may not fear the Road-God's wrath sufficiently yet.

Are these true snake-bites (double holes)? If so, a dab of Slime MAY help a little. It lubes the inside of the tube so tearing is less likely. Snake-bites are basically small tears.

While getting used to roadbiking, use the fattest tires you can. Some people think 25 mm tires may be slightly faster than the smaller 20 mm. And in your case, if the frame can handle cyclocross tires, maybe they'd be a good bet.
re: My tubes keep pinching , Is it the Rims?nuke
Aug 16, 2001 6:17 PM
OK, if it's TRUE pinch flats. Then it is being caused by under inflation of the tire such that the rim is causing the holes as it compressed down onto the tube and onto the concrete/asphalt. So...stop bunny hopping logs! :-)

I'm a clydesdale and keep my tires at full pressure prior to each ride and have never had a pinch flat.

The other way you might be getting a flat from a wheel is the rim tape being poor and letting the spoke nipples puncture the tube. But this won't be a pinch flat, but rather just one hole. If you're not using Velox rim tape, use it. It's only $2.

Other than that...there are no other reasonable possibilities.

And...talc/baby powder. Yeah. It's for lubrication. But it has nothing to do with whether you flat or not.

Ride road & off-road!
Thanks for the advice, we'll give it a try!!!!!Gdhan
Aug 17, 2001 5:09 AM
I really appreciate the advice. I'm going to put it into practice ASAP.
It's awesome to have a forum like this where riders of all levels can interact.
Keep 'em Spinnin'