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Discussion Starter · #1 ·
I keep having a problem with flats on my front wheel. The valve stem gets a tear right at the base where it joins the tube. The first time I just replaced it and didn't look too carefully. The second time I got suspicious and checked out the hole in the rim and it had some sharp edges. I tried filing and smoothing it out, but the same thing happened a third time. At that point I tried getting these aluminum tube shaped things (prest savers)to line the hole and run presta instead or schraeder. Well....then the presta tube went flat with the exact same tear. Now I noticed that the hole in the rim tape is not centered properly, so I straightened it out. Do you think that was the problem all along. I'm feeling pretty boneheaded right about now.
 

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Au'Right!
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If you don't have enough pressure when your riding the tire then you'll roll the tire a tad on the rim and end up tearing the valve stem. Also When your inflating your tires you can accidently tear the valve putting the air chuck on and off the valve. Do you have the lock-nut on your Presta Valve? Thats one of the keys to not ruining your tube.
 

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Domestic Fowl
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I'll second Martinez, it is most likely happening when you remove the pump nozzle from the presta valve. The lock nut won't do anything to prevent this particular problem since the nut is on the wrong side of the rim to help. It would have to be on the inside to help this problem (don't do that). Also note that tightening the lock nut too tight can cause the same problem since it is trying to pull the stem through the hole.

It seems like pump chucks are getting more and more complicated... most have both presta and schrader with a switch, and some being able to automatically detect which valve is inserted into the chuck. With the increased complexity of the newer pump chucks, they often seem harder to use than the older style ones. Often, people(like myself) cram the pump chuck down farther that it needs to go, which may cause it to bind somewhat and make it difficult to remove. Also, sometimes the pump chuck is poorly designed and its just plain hard to get off. I've pulled the stem completely off a tube.

The remedy? Well, if your stem isn't too short you can try to reach in and hold the stem as you remove the pump chuck. Otherwise, try to be conscious of the problem and be careful while removing the pump chuck. I think you said you filed the stem hole a bit, which should help some.


FRC

PS There may be something about the stem on your frot tire that makes it stick in the pump chuck more, or the hole in the front rim may have sharper edges than your back rim.
 

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ride hard take risks
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If you have the plastic type rim strip i belive that would cause your problem, being off set from the hole. What tire pressure are you runnning, what type of bike & what type of riding :confused: You should put baby powder in the tire then rotate the tube in the baby powder to coat. The baby powder allows the tube to move free of the tire flex. You should be able have your tube almost fall out not tear it away from the tire. :cornut:
 

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...place a 3-4" long piece of electrical tape, centered on the valve hole, over the existing rim strip. Then take a knife and poke a small slit in the tape at the valve hole....when you insert the valve stem the tape will remain close to the valve and act as a nice added protectant from the sometimes rough valve hole.

...otherwise I've done 8,000 miles on/off road per year for the last ten years [yes - I know get a life!] and I always have left the valve nut off - as it was one less thing to deal with should I flat during a race.....not a single flat at the valve stem.

best wishes
 

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Discussion Starter · #9 ·
another flat!

So now I'm pretty convinced that the rim tape is to blame. I did okay for a couple weeks then another flat in the exact same place. The rim tape had shifted over so that it overlapped the hole. Should I try the tape trick? Should I get the LBS to replace my rim tape, or should I try to do it? Thanks! I never thought one little thing could be such a PIA!
 

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My boyfriend was late coming home from his usual ride one day due to him having flats on both tubes coming from the same area. They were impossible to repair due to the location. Ends up he bought a few tubes all at the same time from Performance and ended up getting a defunct batch. Where the valve and the tube met they were not manufactured properly and tore.
 

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You need to also make sure you are running a good air pressure, if you run it way to low when you break hard the tire will slip a small amount on the rim and move the tube at the same time. Also on the presta valves dont tighten the nut all the way down that way if your tube does shift on you some it wont rip the valve stem off as quickly.
 

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Discussion Starter · #12 ·
finally figured out

Well, I tried everybody's suggestions and more torn stems later I think it is fixed. The stupid rim strip was creeping around and causing the problem. Not a fan of the Ritchey snap-on rim strip! Got the front wheel fixed and then got my first ever flat in the back. Not counting the time when the obvious problem was a giant thorn sticking out of the side of the tire. Took it off and sure enough, that strip had started creeping over the valve hole.:madmax:
 
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