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#11
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presta valve core failures
In article ,
Mark Hickey wrote: "Llatikcuf" wrote: Mark Heiple wrote: So far my score for flats is: Running over something pointy: 0 Spokes puncturing from the inside: 1 Valve stem tearing: 2 or 3 Valve cores failing: too many to count Any suggestions for a reliable tube? Wow! I've never had a valve fail and I don't buy new tubes, I just patch and reuse the old ones other people leave on the side of the road -- pet peeve of mine. Some of my tubes are 5 years old now. You don't oil the valve cores do you? That's likely, I think... he's gotta be doing SOMETHING different than I am. I've gone through hundreds of tubes over the years, and can't remember more than one or two valve cores failing (if that...). Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $795 ti frame No oil. I use a Blackburn floor pump, but that can't have anything to do with it. |
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#12
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presta valve core failures
In article ,
Jeff Starr wrote: On Thu, 03 Nov 2005 04:40:14 GMT, "Ricardo" wrote: Now we are getting down to it. Why is it that the most complicated part of bike maintained is blowing up the damn tires. I bought a cheap floor pump, hassles, bought an expensive floor pump, hassles. I mean I have this 70 dollar pump and I have to hold the coupling on with one hand and pump with the other, otherwise bend that little thingy. Put it in too far, don't put it in enough. Jesus, I have a wife who will give me a commentary on that. What I do in the privacy of my own garage, how do you keep a valve stem happy? Ricardo I don't understand, do you and the OP have problems with all things mechanical? Where did I say I have a problem with all things mechanical, or didn't know how to inflate a tire? I check and when necessary, which is every few days, pump up my tires. It takes, maybe two minutes. I use a Topeak digital gauge to accurately test pressure. http://www.campmor.com/webapp/wcs/st...memberId=12500 226&productId=30373072 Although the nut that comes with threaded presta valve stems isn't necessary and shouldn't be tightened down, I do use them. Before putting the pump or gauge on, I thread it down to the rim. When done, I snug it against the valve cap. By having it up against the rim, I can push straight down, without fear of doing any damage, by pushing the valve inward. I don't use the nut at all. I have never needed it, it doesn't do anything useful. I use a Topeak Joe Blow Sport Pump, it has two heads, push on, turn lever 90 degrees, and pump. http://www.campmor.com/webapp/wcs/st...memberId=12500 226&productId=39158834 The o-ring in the lever, will wear out, on the two sided pump head. Although I found it easy to replace, I upgraded the head to Topeak's Smarthead. Put it on, pull up lever and pump. Very simple. http://www.performancebike.com/shop/...tegory_ID=4363 The Smarthead hose kit, should work on most brands of pump. I use a blackburn floor pump. I have yet to have a valve stem fail. I have over 8000 miles on my current bike, which gets the tires checked regularly. Congratulations. Maintaining your tires is really very simple. Thanks. Life is Good! Jeff |
#13
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presta valve core failures
"Mark Heiple" wrote in message ... In article , "CEarly" wrote: "Mark Heiple" wrote in message ... I've been having problems with the presta valve cores failing. Usually the bike is just sitting home when it happens. Sometimes the tire goes flat sitting over night, sometimes it goes right after pumping up the tire. A couple times the rubber at the base of the stem tears, but usually it is the valve itself. I've checked by putting a little air in and holding it under water and watch the bubbles. I used to use Continental tubes, which have a removable core. All of them have eventually failed, usually lasting about 1 year. My last one failed a couple days ago. I got 2 Trek/Bontrager tubes (with removable cores). The first I tried was bad out of the box, the 2nd was ok. I have 2 Salsa tubes, which don't have removable cores, they have been ok so far. one has been on the bike since about early spring, the other is still in the box. So far my score for flats is: Running over something pointy: 0 Spokes puncturing from the inside: 1 Valve stem tearing: 2 or 3 Valve cores failing: too many to count Any suggestions for a reliable tube? Thanks. What do you see when you remove the cores? Is the little plastic seat broken? I've had tubes with removable cores leak at the valve, but it has usually been due to the core being a bit loose - easily fixed by tightening it slightly. Occasionally, I've had the valve seat crack and then the core is junk. Cal I haven't seen anything that looked obviously broken. I've tried tightening the cores, but they seem to never hold air again. I'll pump up the tire, it will hold for a few minutes, then go flat again. Take out one of these failed cores and look at the beveled ring of white plastic on it. That's what seals. You'll probably see that it is cracked. If you tighten the core too much in the stem, it seems to crack the seal on the core. This may be what is causing your leaks. I had the same problem and found that if I replace a core that had a cracked seal with one that didn't the leak stopped. Cal |
#14
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presta valve core failures
"Ricardo" wrote:
Now we are getting down to it. Why is it that the most complicated part of bike maintained is blowing up the damn tires. I bought a cheap floor pump, hassles, bought an expensive floor pump, hassles. I mean I have this 70 dollar pump and I have to hold the coupling on with one hand and pump with the other, otherwise bend that little thingy. Put it in too far, don't put it in enough. Jesus, I have a wife who will give me a commentary on that. What I do in the privacy of my own garage, how do you keep a valve stem happy? Ricardo I've been pestered by that issue myownself... I finally replaced all the heads on my floor pumps with the Topeak "SmartHead" (fills both Presta and Shraeder valves without changing anything). Never leaks, never slips, works perfectly every time. MUCH better than anything from Campy or Silca, IMHO. Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $795 ti frame |
#15
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presta valve core failures
Mark Heiple wrote:
Most of the failures have been with the valve core. I had a couple stems tear at the base, but I started putting an extra piece of Velox over the stem, and I haven't had that problem since. When the core fails, it seems like the core isn't making an air tight seal, maybe it unscrews a little. I've tried tightening it, but it has never helped. Once it starts leaking, it won't hold air any more. I will pump the tire up to 120 psi, it will hold for a few minutes, but then it all leaks out again. Do you remove the cores or do they just go bad leaving them as you got them from the factory? Perhaps it's in the handling while out or in the reinsertion where your trouble lies. |
#16
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presta valve core failures
Mark Heiple wrote:
When the core fails, it seems like the core isn't making an air tight seal, maybe it unscrews a little. I've tried tightening it, but it has never helped. Once it starts leaking, it won't hold air any more. I will pump the tire up to 120 psi, it will hold for a few minutes, but then it all leaks out again. I don't mean to insult your intelligence, but are you sure that the valve core is the problem? When I have leaks anywhere in the tube, it usually seems like the air is coming from the stem area because that's the easiest place for the air to escape the tire/rim cavity. The only way to really find the leak is with the tube out of the tire. -- Dave dvt at psu dot edu |
#17
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presta valve core failures
In article , dvt
wrote: Mark Heiple wrote: When the core fails, it seems like the core isn't making an air tight seal, maybe it unscrews a little. I've tried tightening it, but it has never helped. Once it starts leaking, it won't hold air any more. I will pump the tire up to 120 psi, it will hold for a few minutes, but then it all leaks out again. I don't mean to insult your intelligence, but are you sure that the valve core is the problem? When I have leaks anywhere in the tube, it usually seems like the air is coming from the stem area because that's the easiest place for the air to escape the tire/rim cavity. The only way to really find the leak is with the tube out of the tire. I checked the first few by taking them out of the tire and holding under water. The bubbles always came out the valve. After the first few, I quit checking. I don't think they were punctures in the tube, because it never happened during a ride. It would go flat just sitting at home. |
#18
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presta valve core failures
In article ,
Paul Cassel wrote: Mark Heiple wrote: Most of the failures have been with the valve core. I had a couple stems tear at the base, but I started putting an extra piece of Velox over the stem, and I haven't had that problem since. When the core fails, it seems like the core isn't making an air tight seal, maybe it unscrews a little. I've tried tightening it, but it has never helped. Once it starts leaking, it won't hold air any more. I will pump the tire up to 120 psi, it will hold for a few minutes, but then it all leaks out again. Do you remove the cores or do they just go bad leaving them as you got them from the factory? Perhaps it's in the handling while out or in the reinsertion where your trouble lies. I don't do anything with the core, I just put it on and pump it up. I replaced my last bad tube with a trek/bontrager tube (I have 2). The core of the 1st one fell out of the stem as I was taking it out of the wrapper. The 2nd seems to be ok. I suppose I should screw the core back into the 1st and see if holds air, but given my luck, I don't really trust it. |
#19
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presta valve core failures
Mark Heiple wrote:
I checked the first few by taking them out of the tire and holding under water. The bubbles always came out the valve. After the first few, I quit checking. I don't think they were punctures in the tube, because it never happened during a ride. It would go flat just sitting at home. Mark, Again, please don't take offense because I don't wish to offer any, but you are the only person who seems to have this problem. That implies very strongly that there is something different about your behavior or equipment. For example, you say it can't be your pump. Then what can it be? Aside from pump, it must be something you are doing. I can't figure any other factor. I and many here use Conti tubes exclusively. While I'm hardly an old timer on bikes, I've been though enough tubes to say that there are no core issues at all with them. My LBS sells hundreds of them w/o a core failure (I asked). I think you need to examine your fill technique and your pump. -paul |
#20
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presta valve core failures
In article ,
Paul Cassel wrote: Mark Heiple wrote: I checked the first few by taking them out of the tire and holding under water. The bubbles always came out the valve. After the first few, I quit checking. I don't think they were punctures in the tube, because it never happened during a ride. It would go flat just sitting at home. Mark, Again, please don't take offense because I don't wish to offer any, but you are the only person who seems to have this problem. That implies very strongly that there is something different about your behavior or equipment. For example, you say it can't be your pump. Then what can it be? Aside from pump, it must be something you are doing. I can't figure any other factor. I and many here use Conti tubes exclusively. While I'm hardly an old timer on bikes, I've been though enough tubes to say that there are no core issues at all with them. My LBS sells hundreds of them w/o a core failure (I asked). I think you need to examine your fill technique and your pump. -paul No offense taken, I appreciate constructive advice and criticism. Been thinking about what I might be doing different. I do try to keep my tire pressure up, so I usually top them off every few days, usually not more than a week. Judging from what I've read here in the past, that probably isn't putting excessive wear and tear on the valve. I have been leaving the valve cap off. Some guys I know use the cap all the time, others just throw it away and never use it. I'll use it and see if that makes a difference. Maybe something gets in valve and corrodes it, although I thought the cap didn't provide a good enough seal to do any good. My other thought was maybe when I screw the valve nut down, I am using too much force. I have just been making it snug, but maybe I am trying to tighten it too much and breaking it. |
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