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I have had this happen more than I would like to admit. I pump my tires (presta valve) and go out and ride. Sometime along the ride I notice one of my tires going flat (sometimes front, sometimes back). Change it and ride home. Look at the tube and the hole is always in the same place, right at the base of where the valve comes out of the tube. I am thinking it is because when I remove the pump head from the valve I really have to pull to remove it. Which is causing the tube to stretch and create a small hole. What am I doing wrong?!?! Someone else have this problem. Same problem experienced with multiple pumps (Park, Silca). I mentioned it to a couple of riders and no one seems to have this problem. I have Mavic K rims by the way.

Thanks
 

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Check / questions

smooth valve stems or threaded? Maybe switch to different tubes.
Rim tape or no rim tape? Is it in good condition?
Is the area oround ther rim hole smooth? Gently Emory cloth the hole to make it smooth.

Chris
 

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Presuming it's a hole on the INSIDE, then the most likely culprit seems to be the need to deburr the valve stem hole. This is a common cause of flats. If your Ksyrium is one of the older models requiring rimtape, changing it wouldn't hurt, either.

As far as the pump to being hard to get off -- betcha you've got a threaded stem. But I don't think that would wreck the tube on its own.
 

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I had that problem

when I first got my 29er MTB. The first 6 tubes I used all tore at the valve base. All 6 were the same brand. My LBS only had the one brand of 29er tubes. I changed tube brands and it cured that. Lbs no longer carries that brand. Other than that, hold that stem and wiggle the pump head off.
 

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When you're pumping, be sure the valve isn't being pulled around. I've seen a number of over zealous mini pump users damage their stems by unknowingly yanking them around during inflation. And the same can hold true with floor pumps sometimes too if the pump head is pulling the valve at an angle.

Also, with many pumps, the pump doesn't need to be pushed onto the stem until it bottoms out. Doing so would contribute to difficulties removing.

Having a flat repair go flat during inflation sucks. Good luck.
 

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A couple of suggestions. First, buy Michelin tubes or some other brand with smooth valve stems. I have found that threaded valve stems grab more and tend to twist and break more often. Threaded stems also wear out the rubber seal on your pump quicker.

Also, make sure you are not jerking or moving the valve stem around when pumping up your tires. It's easy to do if you are using a hand pup. I prefer floor pumps for that reason, but you still might want to stabilize the valve with your hand if you are breaking that many tubes.
 

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Use a piece of old tube as a second layer.

I cut a 3 inch length of old tube, slice it open the long way, poke a small hole in the middle and stick the valve stem of a tube through that before i install the tube. It provides some extra thickness at the rim hole. I also switched to threadless stems and that semmes to help.

It could also be a brand thing. Santa put a half dozen Giant tubes in my stocking last Christmas. Of the six, four ripped at the valve. This year I'll tell him to stick with the Michelin threadless tubes. :)
 

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One other thing to think about...
If you use that "nut" that screws on to threaded valves you could be tightening it too much. I've had friends get flats for that very reason. Just chuck that nut, it's not needed.
 

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Olive Oil

If you are using threaded valves you may want to try putting a little oive oil or something into the valve on the pump house. I am told by my LBS that this will help remove the pump from the tube valve easier. Also make sure you are pulling the pump off the tube at a stright angle.
 

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tubes aren't as simple as they used to be.

Cheaper brands have given me the same headache. Michelins work well unless you use a CO2 inflator that needs threads or the gasket on your pump head is getting old and won't stay on the threadless valve stem. Lighter tubes are worse than heavier ones, no surprise there. Tubes that achieve light weight by reducing the diameter of the tube rather than recucing the thickness of the rubber worked better, but were damned near impossible for me to patch. I've had good luck with Vittoria tubes recently, but don't know how long they'll continue to be good.
 

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JFR said:
When you're pumping, be sure the valve isn't being pulled around. I've seen a number of over zealous mini pump users damage their stems by unknowingly yanking them around during inflation. And the same can hold true with floor pumps sometimes too if the pump head is pulling the valve at an angle.

Also, with many pumps, the pump doesn't need to be pushed onto the stem until it bottoms out. Doing so would contribute to difficulties removing.

Having a flat repair go flat during inflation sucks. Good luck.
That was going to be my guess.
 

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Advise from a fellow idiot

I was having the same problem. Sometimes I would pump the tires and the stem would rip and leak as soon as I took the pump head off. I know this will sound a bit loopy, but my LBS told me to try putting the nut on the inside of the rim, this will prevent you from pulling on the tube when you remove the pump head. No problems since(fingers crossed).
 

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lonebikeroftheapocalypse said:
I was having the same problem. Sometimes I would pump the tires and the stem would rip and leak as soon as I took the pump head off. I know this will sound a bit loopy, but my LBS told me to try putting the nut on the inside of the rim, this will prevent you from pulling on the tube when you remove the pump head. No problems since(fingers crossed).
Interesting solution. Sounds good provided the stem is long enough.
 

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I dont know, I like 'the breezes' idea of slicing an old inner tube and poking a hole in it. You could even double it (for extra protection) then slip it over the valve stem before mounting the tube.

I keep thinking about the nut possibly wearing into the tube if it's on the underside of the rim.
 

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lonebikeroftheapocalypse said:
I was having the same problem. Sometimes I would pump the tires and the stem would rip and leak as soon as I took the pump head off. I know this will sound a bit loopy, but my LBS told me to try putting the nut on the inside of the rim, this will prevent you from pulling on the tube when you remove the pump head. No problems since(fingers crossed).
I was told the exact same thing once. There was a burr on the valve hole. I forget what we wound up using -- some smooth washer he had around. Worked like a charm.
 

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I've done a similar thing and placed electrical tape around the base of the valve stem (i poke the stem through the tape so that it rests around the base of the stem) I had similar problems with flatting my tubes because of sharp edges around the stem hole on the rim. This fixed it when burring the deges didn't.
 

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Be careful when you pull the pump head off of the valve. I usually put some spit on the valve stem before pumping, to make the removal easier. Unthreadded valve stems help.
 
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