Promoting biking discussion.
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bicycle-forum.com Promoting biking discussion. |
> I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? I've had a couple such failures recently (none ever before). Both were with relatively old inner tubes (a few years old). For the ring, I think it should be tight enough to limit the movement of the valve, but not so tight that it pulls too hard against the rim. The other thing to try to avoid is damaging the inner tube when you're putting it on the rim. A bientot Paul -- Paul Floyd http://paulf.free.fr (for what it's worth) Surgery: ennobled Gerald. |
wrote: > I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? Throw the little thread on ring away. It serves no purpose other than to damage your tube. Most of the failures that I've seen of valve stems occur when big strong guys pump up a recently repaired tyre on the road. Many people naturally look for something to brace the wheel against, so they can push nice and hard on the pump. This causes the pump head to put a lot of sideward pressure on the stem, which then fails. When I pump up my tyres on the road (at home I use a track pump, with a hose to the valve) I do so with the wheel off the bike. I hold the wheel up in the air a little bit, and hold the pump head with one hand, and the handle with the other. The wheel is totally unsupported. This way, I'm not forcing the stem into any weird angles. As a result, I've never had a valve stem fail. Regards, Suzy |
> On Tue, 23 Sep 2003 20:26:47 GMT, Newsgroups > <hlevinger@mindspring.com> wrote: >> I keep getting holes at the juncture of the tube and the >> perpendicular rubber attachment to the threaded metal sleeve. >> >> Question: >> >> Am I inserting the valve stem incorrectly? I try to align the stem >> perfectly centered and perpendicular to the rim. >> >> Also, I asked my lbs how tight to turn the ring over the stem >> threads, and they said "not tight at all: leave it a little loose". >> >> Am I missing something here, or am I just unlucky with blowouts at >> that spot? > > Throw the little thread on ring away. It serves no purpose other > than to damage your tube. > > Most of the failures that I've seen of valve stems occur when big > strong guys pump up a recently repaired tyre on the road. Many > people naturally look for something to brace the wheel against, so > they can push nice and hard on the pump. This causes the pump head > to put a lot of sideward pressure on the stem, which then fails. > > When I pump up my tyres on the road (at home I use a track pump, with > a hose to the valve) I do so with the wheel off the bike. I hold the > wheel up in the air a little bit, and hold the pump head with one > hand, and the handle with the other. The wheel is totally > unsupported. This way, I'm not forcing the stem into any weird > angles. As a result, I've never had a valve stem fail. > > Regards, > > Suzy When holding your wheel in the air like you describe you can also brace the pumphead against a wall or a tree or whatever. This allows you to put more force into the pump without as much as budging the stem and the wheel still hanging freely. -- Perre You have to be smarter than a robot to reply. |
rubber attachment to the threaded metal sleeve. Question: Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and perpendicular to the rim. Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at all: leave it a little loose". >> Check the valve hole in the rim for burrs or sharp edges, If necessary, smooth it down with emery cloth. Then, make sure this area is protected by the rim strip. Don't use the threaded collar for the valve stem. It serves no purpose. Instead, use your thumb when you press the pump head onto the valve to keep from pushing it up into the tire. |
>rubber attachment to the threaded metal sleeve. >Question: >Am I inserting the valve stem incorrectly? I try to align the stem >perfectly centered and perpendicular to the rim. Maybe your straining the tube/valve connection when you remove your pump chuck. A lot of people twist and turn it to remove. I've had the best luck popping it straight off with a thumb on either side. Steve |
> I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? I'm assuming that the valve is tearing out, not that you're getting a hole at the valve from a rim with a sharp spot. Some brands of tubes are more prone to it than others. Switch inner tube brands. I snug the nut lightly. It helps hold the valve when you're putting the tire on and when you're attaching the pump. Once the tire's up to pressure, you could remove it if you were worried about it. But I doubt that's your problem. The other thing to consider is when using a compact frame pump. I put my hand around the pump head and the spoke next to the valve so that when I pump, I put pressure on the spoke, not the valve. David |
news:b02cb.2333$ai7.1876@newsread1.news.atl.earthlink.net... > I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? My bet is that you have a bad batch of tubes, unless they're different brands. If they're the same brand & lot, try something else, and throw those silly rings away. |
> My bet is that you have a bad batch of tubes, unless they're > different brands. If they're the same brand & lot, try something > else, and throw those silly rings away. I'm for that analysis. I find odd that people ask this question here often and always seem to believe it is their own fault when in fact it is a manufacturing flaw. Take the tubes back to the store and demand replacements. There are always smarty responses that place the blame with the use of knurled stem retaining nuts that come with the tube. Considering that the manufacturer offers these as useful attachments and how many thousands of tubes, with jam nuts. have served many thousands of miles, this suggestion is preposterous. Beyond that, I suggest those who believe this story, apply a jam nut to a stem when the tire is completely flat, pump the tire to the usual pressure and see where the lock nut is. It will be about 2-3mm away from the rim. 100psi does more to extend the stem than you can reasonably do with your fingers. Jobst Brandt jobst.brandt@stanfordalumni.org |
> I'm for that analysis. I find odd that people ask this question here > often and always seem to believe it is their own fault when in fact it > is a manufacturing flaw. Take the tubes back to the store and demand > replacements. While it's most likely usually a manufacturing defect, presta valves do seem to be more breakage-prone. I've never had a schraeder valve break, nor have I seen it happen. I have had a presta valve break; and I rode with a group where a rider got a flat; broke the valve while attempting to inflate; was given a tube by another rider; that valve broke; given another tube from yet a different rider, and finally was able to inflate. It was probably the overzealous pumping action which was suggested by somebody else in this thread; but schraeder valves are robust enough to survive that, while one must excersize care with a presta valve. As such, it's not unreasonable that it could be somebody's actions, rather than manufacturing defects, that caused a string of valve stem blows. > Jobst Brandt > jobst.brandt@stanfordalumni.org -- Rick "Still kinda likes presta anyway" Onanian |
>> I'm for that analysis. I find odd that people ask this question >> here often and always seem to believe it is their own fault when in >> fact it is a manufacturing flaw. Take the tubes back to the store >> and demand replacements. > While it's most likely usually a manufacturing defect, Presta valves > do seem to be more breakage-prone. I've never had a Schrader valve > break, nor have I seen it happen. I have had a Presta valve break; > and I rode with a group where a rider got a flat; broke the valve > while attempting to inflate; was given a tube by another rider; that > valve broke; given another tube from yet a different rider, and > finally was able to inflate. That's a bit off subject. The problem here is a stem separating from the tube rubber, not a stem breaking off. These stem separations are all manufacturing failures. Jobst Brandt jobst.brandt@stanfordalumni.org |
>miles, this suggestion is preposterous. Beyond that, I suggest those >who believe this story, apply a jam nut to a stem when the tire is >completely flat, pump the tire to the usual pressure and see where the >lock nut is. It will be about 2-3mm away from the rim. 100psi does >more to extend the stem than you can reasonably do with your fingers. Some people then continue to do up the nut, of course. -- David Damerell <damerell@chiark.greenend.org.uk > Distortion Field! |
>> miles, this suggestion is preposterous. Beyond that, I suggest >> those who believe this story, apply a jam nut to a stem when the >> tire is completely flat, pump the tire to the usual pressure and >> see where the lock nut is. It will be about 2-3mm away from the >> rim. 100psi does more to extend the stem than you can reasonably >> do with your fingers. > Some people then continue to do up the nut, of course. The point is that with your fingers, you cannot exert any significant force on the stem as is evident from the initial tightening before inflation. Therefore, this is as always an urban legend. If it were the source of stem separations, that is the first part that would no longer be offered with new tubes. Jobst Brandt jobst.brandt@stanfordalumni.org |
<jobst.brandt@stanfordalumni.org > wrote in message news:vE8cb.23896$dk4.761322@typhoon.sonic.net... > Peter Cole writes: > > > My bet is that you have a bad batch of tubes, unless they're > > different brands. If they're the same brand & lot, try something > > else, and throw those silly rings away. > > I'm for that analysis. I find odd that people ask this question here > often and always seem to believe it is their own fault when in fact it > is a manufacturing flaw. Take the tubes back to the store and demand > replacements. I'm for this analysis too. Furthermore, the half-dozen or so failures I've had have been with a single brand -- Specialized. Unfortunately, it's the only brand most shops seem to sell, and they become indignant when you suggest that such a revered brand name would sell an inferior product. These Specialized tubes that fail with such frequency may all be from the same batch, which has been lying around for years on bike shop shelves. Look for "no-name" tubes, the ones with Chinese lettering on the box. They're cheaper, and likely better. > There are always smarty responses that place the blame with the use of > knurled stem retaining nuts that come with the tube. Considering that > the manufacturer offers these as useful attachments and how many > thousands of tubes, with jam nuts. have served many thousands of > miles, this suggestion is preposterous. Beyond that, I suggest those > who believe this story, apply a jam nut to a stem when the tire is > completely flat, pump the tire to the usual pressure and see where the > lock nut is. It will be about 2-3mm away from the rim. 100psi does > more to extend the stem than you can reasonably do with your fingers. Test, schmest, everyone knows you're doing it wrong... ;-) Matt O. |
> I'm for this analysis too. Furthermore, the half-dozen or so failures > I've had have been with a single brand -- Specialized. > > Unfortunately, it's the only brand most shops seem to sell, and they My LBS has a variety of brands of tubes (possibly the only thing of which he has a variety!). I've been happy with Bontrager Superlight tubes (they come in a pretty silver box). Regardless of weight (reported as 65g on the box for 700x18c-25c), they fold up very small and are easy to stuff spares into a small space, and are as robust as anything else I've used (or maybe even better). That's my unscientific opinion on tubes. :) > Matt O. -- Rick Onanian |
"Matt O'Toole" <matt@deltanet.com > wrote: > I'm for this analysis too. Furthermore, the half-dozen or so > failures I've had have been with a single brand -- Specialized. That is exactly my experience as well! |
<< I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the threaded metal sleeve. >> I bet ten bucks you tear the stem away from the tube from overzealous pumping technique. The question of how tight to tighten the nut is interesting. I believe that overtightening the nut makes it easier for the stem to tear away, but leaving it loose is not good either. I say tighten it very modestly. If not bad pumping, a bad batch of tubes. Robert |
"R15757" <r15757@aol.com > wrote in message news:20030923222150.01706.00000119@mb-m29.aol.com... > howard wrote: > > << I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. >> Not quite the thread I thought it was... A couple weeks ago, after topping off the pressure, I had a presta valve core go shooting out of the stem, bounce off the ground and leave for parts unknown! That was the first time in about 30 years of using presta values that I had a core leave the stem... John |
off the pressure, I had a presta valve core go shooting out of the stem, bounce off the ground and leave for parts unknown! That was the first time in about 30 years of using presta values that I had a core leave the stem... John >> Cool. Robert |
I get two schools of thought on the ring that holds the stem to the rim: A) Throw it away B) Tighten it just enough to hold the stem against the rim, but not too tight I wonder how there could be such diametrically opposed views. Somebody's gotta be right, no? I like this thought: "I bet ten bucks you tear the stem away from the tube from overzealous pumping technique." That has the ring of truth to it. Thanks again Howard Levinger "Newsgroups" <hlevinger@mindspring.com > wrote in message news:b02cb.2333$ai7.1876@newsread1.news.atl.earthlink.net... > I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? > > TIA > > Howard > > |
--------------000100020209070903010807 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Howard: I'm from the "A" school. Why? Because you really don't want the stem against the rim! You want the tube to be seated WITHIN the tire all the way around the tire - the stem is only how you get the air into the tire. What you really want to do is to start inflating the tire with the stem pushed into the tire, not pulled out against the rim. After you have 30 lbs or so of air in the tire you no longer have to push the valve in as the air pressure will hold the tube in place. MOO, Matt Howard wrote: >Thanks all for your help. > >I get two schools of thought on the ring that holds the stem to the rim: >A) Throw it away >B) Tighten it just enough to hold the stem against the rim, but not too >tight > >I wonder how there could be such diametrically opposed views. Somebody's >gotta be right, no? > >I like this thought: >"I bet ten bucks you tear the stem away from the tube from overzealous >pumping >technique." > >That has the ring of truth to it. > >Thanks again > >Howard Levinger > >"Newsgroups" <hlevinger@mindspring.com> wrote in message >news:b02cb.2333$ai7.1876@newsread1.news.atl.earthlink.net... > > >>I keep getting holes at the juncture of the tube and the perpendicular >>rubber attachment to the threaded metal sleeve. >> >>Question: >> >>Am I inserting the valve stem incorrectly? I try to align the stem >>perfectly centered and perpendicular to the rim. >> >>Also, I asked my lbs how tight to turn the ring over the stem threads, and >>they said "not tight at all: leave it a little loose". >> >>Am I missing something here, or am I just unlucky with blowouts at that >>spot? >> >>TIA >> >>Howard >> >> >> >> > > > > --------------000100020209070903010807 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" > <html > <head > <title ></title> </head > <body > Howard:<br > <br > I'm from the "A" school. Why? Because you really don't want the stem against the rim! You want the tube to be seated WITHIN the tire all the way around the tire - the stem is only how you get the air into the tire. What you really want to do is to start inflating the tire with the stem pushed into the tire, not pulled out against the rim. After you have 30 lbs or so of air in the tire you no longer have to push the valve in as the air pressure will hold the tube in place. <br > <br > MOO,<br > Matt<br > <br > Howard wrote:<br > <blockquote type="cite" cite="mid%25y8cb.4208$ai7.216@newsread1.news.atl.earthlink.net" > <pre wrap="" >Thanks all for your help. I get two schools of thought on the ring that holds the stem to the rim: A) Throw it away B) Tighten it just enough to hold the stem against the rim, but not too tight I wonder how there could be such diametrically opposed views. Somebody's gotta be right, no? I like this thought: "I bet ten bucks you tear the stem away from the tube from overzealous pumping technique." That has the ring of truth to it. Thanks again Howard Levinger "Newsgroups" <a class="moz-txt-link-rfc2396E" href="mailto:hlevinger@mindspring.com" ><hlevinger@mindspring.com></a> wrote in message <a class="moz-txt-link-freetext" href="news:b02cb.2333$ai7.1876@newsread1.news.atl.earthlink.net" >news:b02cb.2333$ai7.1876@newsread1.news.atl.earthlink.net</a>... </pre > <blockquote type="cite" > <pre wrap="" >I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the threaded metal sleeve. Question: Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and perpendicular to the rim. Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at all: leave it a little loose". Am I missing something here, or am I just unlucky with blowouts at that spot? TIA Howard </pre > </blockquote > <pre wrap="" ><!----> </pre > </blockquote > <br > </body > </html > --------------000100020209070903010807-- |
"Newsgroups" <hlevinger@mindspring.com > wrote in message news:b02cb.2333$ai7.1876@newsread1.news.atl.earthlink.net... > I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? > > TIA > > Howard > Are your rims drilled for schrader valves? |
Newsgroups wrote: > I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? Why do you add the outer lockring? We don't, as we see no useful purpose. -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
> Why do you add the outer lockring? We don't, as we see no useful purpose. I don't know why the OP does it, but with shorter stems, I find that they disappear before I can get the pump head on them, no matter how I try to hold. -- Rick Onanian |
> > Why do you add the outer lockring? We don't, as we see no useful purpose. Hi, when I switched wheels and they had presta valves, my LBS mechanic told me that he didn't use the rings. His reason was that people keep tightening them until they do damage. That was good enough for me, but I have found a need for the ring. I have one tire that when I try to top off the pressure, the pump nozzle wouldn't engage properly. The pump is a Joe Blow Sport with the two sided nozzle. It works fine on the three other presta valves, consistently, so I thnk it's the valve, not the pump. Anyway, to get the pump to work, I have to press down, very hard, to get it on far enough to catch[?]. I was afraid I would wreck the tube, doing this, so I put the nut on and run it down to the rim, before filling. When I am done, I put the cap on and then back the nut off, so it is against the cap. So, in this case, it has a useful purpose. Some one else mentioned that they use them when mounting the tube and tire, that sounds like a good idea. In the past, I've had a few Schraeder valves, end up crooked, it seem that the temporary use of the presta nut would prevent this. Life is Good! Jeff |
news:10c5841f.0309240628.5001b4ee@posting.google.com... > > Anyway, to get the pump to work, I have to press down, very hard, to > get it on far enough to catch[?]. I was afraid I would wreck the tube, > doing this, so I put the nut on and run it down to the rim, before > filling. I'd be more worried about ruining the pump. The rubber grommet that seals against the valve gets all torn up when you force the head on the valve, lose the bad tube, or unscrew the cap on the pump head a bit. > When I am done, I put the cap on and then back the nut off, > so it is against the cap. So, in this case, it has a useful purpose. No, just throw those away too. |
Tossing Presta stem nuts away, preferably over the left shoulder under a full moon will prevent leaky stems. This is a classic interpretation of misplaced cause and effect, there being no linkage between stem separations and jam nuts. Since the voodoo has progressed as far as it has, many people who have tossed their jam nuts are still having stem separations while not realizing the irony of the practice. Jobst Brandt jobst.brandt@stanfordalumni.org |
news:2Jncb.24130$dk4.769468@typhoon.sonic.net... > I'm glad to see voodoo is still well and alive on wreck.bike.tech. > Tossing Presta stem nuts away, preferably over the left shoulder under > a full moon will prevent leaky stems. No need to throw them away if you just buy tubes without nuts. Means the pump head seals better, too, as there's no thread. All the stem seperations I've witnessed have been while big burly guys put new tubes in on the road, then brace the bike against something so they can push harder on the pump (all the while bending the poor stem out of shape). Regards, Suzy |
>> I'm glad to see voodoo is still well and alive on wreck.bike.tech. >> Tossing Presta stem nuts away, preferably over the left shoulder >> under a full moon will prevent leaky stems. > No need to throw them away if you just buy tubes without nuts. > Means the pump head seals better, too, as there's no thread. > All the stem seperations I've witnessed have been while big burly > guys put new tubes in on the road, then brace the bike against > something so they can push harder on the pump (all the while bending > the poor stem out of shape). You lie. Presta stems with threads do not bend. The best they can do is break off, but this has nothing to do with jam nuts and even less with stem separations from the tube. Jobst Brandt jobst.brandt@stanfordalumni.org |
news:2Jncb.24130$dk4.769468@typhoon.sonic.net... > I'm glad to see voodoo is still well and alive on wreck.bike.tech. > Tossing Presta stem nuts away, preferably over the left shoulder under > a full moon will prevent leaky stems. This is a classic > interpretation of misplaced cause and effect, there being no linkage > between stem separations and jam nuts. Since the voodoo has > progressed as far as it has, many people who have tossed their jam > nuts are still having stem separations while not realizing the irony > of the practice. > The real question is, what is the value of jam nuts for tubes? -- Robin Hubert <cv2572@earthlink.net > |
news:kDtcb.9121$ai7.1127@newsread1.news.atl.earthlink.net... > The real question is, what is the value of jam nuts for tubes? Anyone else think that sounded dirty somehow? Bill "me neither" S. |
> The real question is, what is the value of jam nuts for tubes? They hold the valve in place while the pump chuck is pushed on. Useful when using a tight-fitting push-to-fit pump head - particularly on a flat tyre. That is a "useful purpose". ~PB |
> I'm glad to see voodoo is still well and alive on wreck.bike.tech. > Tossing Presta stem nuts away, preferably over the left shoulder under > a full moon will prevent leaky stems. This is a classic > interpretation of misplaced cause and effect, there being no linkage > between stem separations and jam nuts. Since the voodoo has > progressed as far as it has, many people who have tossed their jam > nuts are still having stem separations while not realizing the irony > of the practice. I talked with another dealer who sells Specialized product (I do not) and confirmed Jobst's assertion that this is a known issue with whoever the low bidding manufacturer for that tube is currently. It seems that whoever makes that tube now has been unable to consisently get the valve to stick in the tube. The phenomenon we see here is a tear at one side of the valve base,(seen mostly on big tires like 700-35/38 underinflated) not a complete separation.They are two different things. -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
> >>Why do you add the outer lockring? We don't, as we see no useful purpose. Jeff Starr wrote: > Hi, when I switched wheels and they had presta valves, my LBS mechanic > told me that he didn't use the rings. His reason was that people keep > tightening them until they do damage. That was good enough for me, but > I have found a need for the ring. I have one tire that when I try to > top off the pressure, the pump nozzle wouldn't engage properly. The > pump is a Joe Blow Sport with the two sided nozzle. It works fine on > the three other presta valves, consistently, so I thnk it's the valve, > not the pump. > > Anyway, to get the pump to work, I have to press down, very hard, to > get it on far enough to catch[?]. I was afraid I would wreck the tube, > doing this, so I put the nut on and run it down to the rim, before > filling. When I am done, I put the cap on and then back the nut off, > so it is against the cap. So, in this case, it has a useful purpose. > > Some one else mentioned that they use them when mounting the tube and > tire, that sounds like a good idea. In the past, I've had a few > Schraeder valves, end up crooked, it seem that the temporary use of > the presta nut would prevent this. > Life is Good! You touch on another tangential subject. When ridden with insufficient pressure, the tire casing's exaggerated flexing causes the tire to creep around the rim. The tube is drawn along with it, which is fine so far as it goes. The valve can't move though. It's slipped right through the sluminum rim. So in such a situation, one rider might see that valve crooked and remember to both remount the tire and tube and also check the pressure more frequently. Another rider with the same issue but a firmly fastened valve ring will just keep riding until the valve tears away from the tube. -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
>-- Not on the tube but , oh boy, are they useful for other things, like spacing toe clips, for instance. Phil Brown |
>> I keep getting holes at the juncture of the tube and the >> perpendicular rubber attachment to the threaded metal sleeve. >> Question: >> Am I inserting the valve stem incorrectly? I try to align the stem >> perfectly centered and perpendicular to the rim. >> Also, I asked my lbs how tight to turn the ring over the stem >> threads, and they said "not tight at all: leave it a little loose". >> Am I missing something here, or am I just unlucky with blowouts at >> that spot? > Why do you add the outer lockring? We don't, as we see no useful > purpose. The lock ring prevents the stem from being pushed into the wheel when pushing on many of the common pump heads and while manually pumping with a hose-less hand pump (typically a Silca Impero of old). Jobst Brandt jobst.brandt@stanfordalumni.org |
>>> I keep getting holes at the juncture of the tube and the >>> perpendicular rubber attachment to the threaded metal sleeve. > >>> Question: > >>> Am I inserting the valve stem incorrectly? I try to align the stem >>> perfectly centered and perpendicular to the rim. > >>> Also, I asked my lbs how tight to turn the ring over the stem >>> threads, and they said "not tight at all: leave it a little loose". > >>> Am I missing something here, or am I just unlucky with blowouts at >>> that spot? > >> Why do you add the outer lockring? We don't, as we see no useful >> purpose. > > The lock ring prevents the stem from being pushed into the wheel when > pushing on many of the common pump heads and while manually pumping > with a hose-less hand pump (typically a Silca Impero of old). I've never experienced this. I always chuck the ring. When installing a tube and inflating, I just mash on the tire opposite the stem with my thumb and the pump head goes on fine. |
>>> Why do you add the outer lockring? We don't, as we see no useful >>> purpose. >> The lock ring prevents the stem from being pushed into the wheel >> when pushing on many of the common pump heads and while manually >> pumping with a hose-less hand pump (typically a Silca Impero of >> old). > I've never experienced this. I always chuck the ring. > When installing a tube and inflating, I just mash on the tire > opposite the stem with my thumb and the pump head goes on fine. That depends on what sort of tire you are inflating, but when inflation reaches 30psi, you can no longer flatten the tire against the back of the stem and the stem will recede into the tire with a classic frame fit pump (like Silca Impero). THat is where this came from and in the days of tubulars, it was the smooth stem tubes that caused pumping problems, having no jam nut to keep them from submerging. In any case, these nuts do not cause stem separation. If they did, I would have several hundred separated stems. I don't. I have only aless than a dozen of which I made pictures available at: As you can see in the picture in the URL below, even threadless stems separate. Not the long stem near the chain. http://www.yellowjersey.org/photosfromthepast/VALVE.JPG Jobst Brandt jobst.brandt@stanfordalumni.org |
>>> Why do you add the outer lockring? We don't, as we see no useful >>> purpose. >> The lock ring prevents the stem from being pushed into the wheel >> when pushing on many of the common pump heads and while manually >> pumping with a hose-less hand pump (typically a Silca Impero of >> old). > I've never experienced this. I always chuck the ring. > When installing a tube and inflating, I just mash on the tire > opposite the stem with my thumb and the pump head goes on fine. That depends on what sort of tire you are inflating, but when inflation reaches 30psi, you can no longer flatten the tire against the back of the stem and the stem will recede into the tire with a classic frame fit pump (like Silca Impero). That is where this came from and in the days of tubulars, it was the smooth stem tubes that caused pumping problems, having no jam nut to keep them from submerging. In any case, these nuts do not cause stem separation. If they did, I would have several hundred separated stems. I don't. I have only fewer than a dozen of which I made pictures available at: http://www.yellowjersey.org/photosfromthepast/VALVE.JPG As you can see in the picture in the URL, even threadless stems separate. Note the long stem near the chain. Jobst Brandt jobst.brandt@stanfordalumni.org |
> Why do you add the outer lockring? We don't, as we see no useful > purpose. jobst.brandt@stanfordalumni.org replies: > The lock ring prevents the stem from being pushed into the wheel when > pushing on many of the common pump heads and while manually pumping > with a hose-less hand pump (typically a Silca Impero of old). I haven't used lock rings on presta valves in years and haven't had a problem pressing a pump head over the end of a valve. If the tire is flat or nearly so before attaching the pump head, I just press down on the outside of the tire at the valve to keep the stem from disappearing into the rim. This works the same way with Shrader valves. -- Bill Bushnell |
> I haven't used lock rings on presta valves in years and haven't had a > problem pressing a pump head over the end of a valve. If the tire is > flat or nearly so before attaching the pump head, I just press down > on the outside of the tire at the valve to keep the stem from > disappearing into the rim. But it is easier to use a lockring. ~PB |
> Bill Bushnell wrote: >> I haven't used lock rings on presta valves in years and haven't had a >> problem pressing a pump head over the end of a valve. If the tire is >> flat or nearly so before attaching the pump head, I just press down >> on the outside of the tire at the valve to keep the stem from >> disappearing into the rim. > But it is easier to use a lockring. The lock ring is an extra piece of hardware that needs to be threaded on and off the valve stem when changing tubes. Most modern hand pumps use a lever-operated cam that when open allows the pump head to slide with little effort over the valve and when closed compresses the washer inside the pump head so that it closes tightly around the valve preventing air leakage. Indeed, the most efficient hand pumps on the market today operate like small floor pumps, removing the pump head to the end of a short hose and allowing the operator to use one's full weight when pumping. Perhaps the lock ring is a vestige from the days when cyclists used hand pumps with cam-less pump heads. -- Bill Bushnell |
>> But it is easier to use a lockring. > > The lock ring is an extra piece of hardware that needs to be threaded > on and off the valve stem when changing tubes. Most modern hand > pumps use a lever-operated cam that when open allows the pump head to > slide with little effort over the valve and when closed compresses > the washer inside the pump head so that it closes tightly around the > valve preventing air leakage. A lot of us use Silca floor pumps (which are still being sold today) and sometimes cheap hand pumps that do not have a lever and cam. > Indeed, the most efficient hand pumps > on the market today operate like small floor pumps, removing the pump > head to the end of a short hose and allowing the operator to use > one's full weight when pumping. > > Perhaps the lock ring is a vestige from the days when cyclists used > hand pumps with cam-less pump heads. Millions of cyclists still do use them. ~PB |
>>> I haven't used lock rings on Presta valves in years and haven't >>> had a problem pressing a pump head over the end of a valve. If >>> the tire is flat or nearly so before attaching the pump head, I >>> just press down on the outside of the tire at the valve to keep >>> the stem from disappearing into the rim. >> But it is easier to use a lockring. > The lock ring is an extra piece of hardware that needs to be > threaded on and off the valve stem when changing tubes. Most modern > hand pumps use a lever-operated cam that when open allows the pump > head to slide with little effort over the valve and when closed > compresses the washer inside the pump head so that it closes tightly > around the valve preventing air leakage. Indeed, the most efficient > hand pumps on the market today operate like small floor pumps, > removing the pump head to the end of a short hose and allowing the > operator to use one's full weight when pumping. > Perhaps the lock ring is a vestige from the days when cyclists used > hand pumps with cam-less pump heads. You assume that the whole world thinks as you do, but they don't, and you'll find many people who use them on their wheels. The jam nuts have a function even after the pump head has been attached. You might be surprised how clumsy most riders are when it comes to inflating a tire. A wobbly stem without a jam nut makes that worse. Besides, if people aren't using these knurled nuts, why tell them that they are the cause of their stem separations... which they aren't. Jobst Brandt jobst.brandt@stanfordalumni.org |
> You assume that the whole world thinks as you do, but they don't, and > you'll find many people who use them on their wheels. The jam nuts > have a function even after the pump head has been attached. You might > be surprised how clumsy most riders are when it comes to inflating a > tire. A wobbly stem without a jam nut makes that worse. Why are you calling this a "jam nut" and not just a nut? from http://dictionary.reference.com/search?q=jam%20nut Check nut, Jam nut, Lock nut, a nut which is screwed up tightly against another nut on the same bolt or screw, in order to prevent accidental unscrewing of the first nut. Tom Ace |
>> You assume that the whole world thinks as you do, but they don't, >> and you'll find many people who use them on their wheels. The jam >> nuts have a function even after the pump head has been attached. >> You might be surprised how clumsy most riders are when it comes to >> inflating a tire. A wobbly stem without a jam nut makes that >> worse. > Why are you calling this a "jam nut" and not just a nut? > from http://dictionary.reference.com/search?q=jam%20nut > Check nut, Jam nut, Lock nut, a nut which is screwed up > tightly against another nut on the same bolt or screw, > in order to prevent accidental unscrewing of the first nut. As you see, words have more than one use and in this case the distinction is that it is not a structural nut as in "nut & bolt" that holds a mechanical part in place but rather one that limits motion. Jam nuts are called "counter nuts" in some application because they do not hold the load but counter any motion of the nut that holds the load. Unfortunately most of these applications are misunderstood because the jam nut is in fact the one underneath the holding nut. It is a jam nut because it retains position rather than load. Jobst Brandt jobst.brandt@stanfordalumni.org |
> Bill Bushnell writes: >> Perhaps the lock ring is a vestige from the days when cyclists used >> hand pumps with cam-less pump heads. > You assume that the whole world thinks as you do, but they don't, and > you'll find many people who use them on their wheels. No doubt, otherwise this thread would die. So, how does one manage without a lock ring to inflate a Shrader valve tube using a non-locking pump head such as found at the local gas station? > The jam nuts > have a function even after the pump head has been attached. You might > be surprised how clumsy most riders are when it comes to inflating a > tire. A wobbly stem without a jam nut makes that worse. Clumsy pumpers might best be served by a modern frame pump that does away with the risk of a valve stem torn when pumping. However, I don't believe that using a lock ring decreases this risk unless one takes the trouble to tighten the lock ring as the tire pressure increases during pumping, something I think most cyclists won't do. > Besides, if people aren't using these knurled nuts, why tell them that > they are the cause of their stem separations... which they aren't. Wrong attribution. I never suggested that the use of presta lock rings (knurled nuts) led to torn valve stems, only that they were unnecessary, even when using non-locking pump heads. -- Bill Bushnell |
a lost atribute was here > >>>I keep getting holes at the juncture of the tube and the >>>perpendicular rubber attachment to the threaded metal sleeve. > >>>Question: > >>>Am I inserting the valve stem incorrectly? I try to align the stem >>>perfectly centered and perpendicular to the rim. > >>>Also, I asked my lbs how tight to turn the ring over the stem >>>threads, and they said "not tight at all: leave it a little loose". > >>>Am I missing something here, or am I just unlucky with blowouts at >>>that spot? > Andrew Muzi wrotes: >>Why do you add the outer lockring? We don't, as we see no useful >>purpose. Jobst Brandt suggested > The lock ring prevents the stem from being pushed into the wheel when > pushing on many of the common pump heads and while manually pumping > with a hose-less hand pump (typically a Silca Impero of old). I have heard that. I personally grasp the pump head in my hand, which is wrapped around the rim and tire so as not to press against an unsupported valve. By pressing down a bit from the tire side for the first few strokes, the valve is kept well out of the rim even with my old Silca, which I keep on one bike. I can imagine this problem with a fat mountain style tire but I have no experience pumping those. On any reasonable road width, the vestigal rings have not been missed by me. But, hey, if you like 'em, go for it. I am not "opposed" as much as mystified. I might add that my pumping experiences with inner tubes are exclusively on the tires of people I have met by the side of the road as I do not use that system myself. I have inflated a broad selection of sizes and qualities of road tires uneventfully with a Silca over the years. (It's amazing how few riders are prepared to deal with a puncture) In my service department, corroded rings and overtightened rings are common. If you're going to use a valve ring, it should not be secured with a plier and all one's might -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
> In my service department, corroded rings and overtightened rings are > common. If you're going to use a valve ring, it should not be > secured with a plier and all one's might That doesn't mean a reasonable rider is going to get the ring corroded or tight beyond manual loosening. As I said, I've had many many Presta stems using the knurled jam nut on my bicycle, first with tubulars and later with clinchers and have not had a corroded lock ring or one that could not be removed by hand easily. A knurled ring is obviously made for hand use. That is what knurling is for. Jobst Brandt jobst.brandt@stanfordalumni.org |
A Muzi <am@yellowjersey.org > wrote: > Why do you add the outer lockring? We don't, as we see no useful > purpose. Helpful when your pump is a Silca with Campy head... |
"Newsgroups" <hlevinger@mindspring.com > wrote: >I keep getting holes at the juncture of the tube and the perpendicular >rubber attachment to the threaded metal sleeve. > Are you a mountain biker? I have had a valve stem tear off because the tire shifted on the rim while braking heavily on steep,rocky descents. Presumably the wheel loses contact with the ground when going over a rock, the wheel immediately locks up, and recontacting the ground provides an impulse that shifts the tire. Very often after a steep descent I notice that the tire has shifted a bit, and the valve stem is now at a slant with respect to the rim. I then unmount and remount the tire.The cures suggested in this newsgroup were checking air pressure (I had 60 psi), checking that the rim and tire hadn't been treated with some sort of silicone stuff for easy mounting (mine weren't), and gluing the tire to the rim (haven't tried this yet). -- Ned Mantei Department of Cell Biology, Swiss Federal Institute of Technology CH-8093 Zurich, Switzerland |
> I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? > > TIA > > Howard If it is a wheel that you've used without any valve problems in the past, the problem must be poorly manufactured tubes. If it is a new wheel, the problem still is probably due to poorly made tubes, but do check for sharp edges and burrs in the rim's valve hole. I think well made tubes should have valves that can withstand the rigors of being pumped up with frame pumps or mini pumps and, of course floor pumps. It is very unlikely that you are doing anything way wrong in pumping up your tires, but if not sure, review your technique with your LBS. Perhaps you could see if your LBS has another brand of tube for you to try. If the tubes that give problems are made in Asia, then try German Continental tubes or visa versa. Regarding the rings, since everything stays together and works fine without them, I leave them off. My wife, however, likes them for some reason and that's good enough for me, so I put them on her bike, screwed on snuggly enough so they don't come off. Steve Shapiro shaps@thermacell.net |
Stem rings? Quit using them after a long cold walk home one winter @20 years ago, front flat and could *not* get the ring off ("frozen" on?), which had been installed "barely finger tight", due to other torque experiments to failure. Fingers cold also, removal attempts didn't warm them up any. Presta stems need gentle treatment, just ruined my first one in about as many (20) years, my fault due to impatience. Since it was one from a pair (or more) of like tubes that have worked fine, doubt "defect" theory on this one at least. Or maybe that shows that even marginal ones will work fine up to about my usual 110-5 lbs. if handled with care. I keep the caps and rings on new tubes until I use them (easy ID), and have had people ask for them when they see I'm not installing them. To each their own. --Tom Paterson |
ago, front flat and could *not* get the ring off ("frozen" on?), which had been installed "barely finger tight", due to other torque experiments to failure. Fingers cold also, removal attempts didn't warm them up any... >> <snip > --Tom Paterson >> Tom if you had a patch kit along you could've easily patched the tube without removing the stem from the rim. Robert too late now eh |
> >Tom if you had a patch kit along you could've easily patched the tube without >removing the stem from the rim. > >Robert >too late now eh Ouch (a distant, faint ouch). Much, much too late, but thanks for the idea... It was around 20-25 degrees F. outside, getting dark, maybe that's why I never thought of trying, if indeed I was even carrying a patch kit in that weather. Anyone ever try a patch "in the cold" and get it to stick? --TP |
news:20030924152457.07884.00000093@mb-m05.aol.com... > >From: r15757@aol.com (R15757) > > > > >Tom if you had a patch kit along you could've easily patched the tube without > >removing the stem from the rim. > > > >Robert > >too late now eh > > Ouch (a distant, faint ouch). Much, much too late, but thanks for the idea... > > It was around 20-25 degrees F. outside, getting dark, maybe that's why I never > thought of trying, if indeed I was even carrying a patch kit in that weather. > > Anyone ever try a patch "in the cold" and get it to stick? --TP Sure, both on & off road. A lot of us cycle year 'round here in Boston, I've patched flats in single digits (F), not a pleasant experience, but I think patching in the rain is worse. I have managed to patch without removing the tube (or even the wheel) also. |
> I keep getting holes at the juncture of the tube and the perpendicular > rubber attachment to the threaded metal sleeve. > > Question: > > Am I inserting the valve stem incorrectly? I try to align the stem > perfectly centered and perpendicular to the rim. > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > they said "not tight at all: leave it a little loose". > > Am I missing something here, or am I just unlucky with blowouts at that > spot? Are you using a floor pump or a portable pump? If it's a portable pump (except for pumps like the topeak morph that mimics a floor pump), then your pumping technique could be to blame. If a floor pump, then it's more likely to be a defective batch of tubes. |
Tubes that have broken: Performance "Thorn-resistant" (2) Specialized (1) Schwinn "Thorn-resistant" (1) Am in the process of checking the hole (presta hole) for burrs or sharp edges. Will only push on the (inner) valve stem from the outside of the tire. Thanks all. Howard Levinger "Gary Young" <garyyoung3@hotmail.com > wrote in message news:bfbe6ed3.0309241300.3cba1bd3@posting.google.com... > "Newsgroups" <hlevinger@mindspring.com> wrote in message news:<b02cb.2333$ai7.1876@newsread1.news.atl.earthlink.net >... > > I keep getting holes at the juncture of the tube and the perpendicular > > rubber attachment to the threaded metal sleeve. > > > > Question: > > > > Am I inserting the valve stem incorrectly? I try to align the stem > > perfectly centered and perpendicular to the rim. > > > > Also, I asked my lbs how tight to turn the ring over the stem threads, and > > they said "not tight at all: leave it a little loose". > > > > Am I missing something here, or am I just unlucky with blowouts at that > > spot? > > Are you using a floor pump or a portable pump? If it's a portable pump > (except for pumps like the topeak morph that mimics a floor pump), > then your pumping technique could be to blame. If a floor pump, then > it's more likely to be a defective batch of tubes. |
> Floor pump. > > Tubes that have broken: > Performance "Thorn-resistant" (2) > Specialized (1) > Schwinn "Thorn-resistant" (1) > > Am in the process of checking the hole (presta hole) for burrs or sharp > edges. Will only push on the (inner) valve stem from the outside of the > tire. Well, I'm just speculating, but could it be that thorn-resistant tubes (three of the four tubes in your sample) are more prone to this problem? Perhaps the thicker rubber is less tolerant of side-to-side movements of the stem? Of course, the stem is on the inside surface of the tube, where I believe the rubber is thinnest. But even so, I would expect the rubber there to be thicker on a thorn-proof tube than on a conventional tube. |