Is it normal for tubular tires to lose pressure over a few days?
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Is it normal for tubular tires to lose pressure over a few days?
I have a pair of Tufo S3 lites, and my front tire has been losing pressure slowly, and over a period of 3 to 4 days it gets significantly soft to finger pinching and needs to be re-inflated. Is this normal? The weird thing is that the rear tire was pumped up to 130psi about 3 weeks ago and shows very little loss in pressure... Could I be experiencing a slow leak in my front? Should go the sealant route?
Thanks!
Thanks!
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Some tubulars come with latex tubes -- usually it's the nicer tubulars because the latex tubes are both lighter and a bit more supple. Anyway, latex tubes lose 15-20 psi or so per day. You have to pump them up every day.
More and more tubular manufacturers are going with ultrathin butyl rubber (black rubber) tubes, which don't lose air anywhere near as much (it takes a week or two to lose that same 15-20 psi). Butyl tubes used to be thick, heavy, and killed the good ride, causing them to be found only on cheap tubulars. Now the ultrathin ones are comparable in weight to latex, and by being so thin are much more supple as well. Consequently you see them in a variety of really nice tires. Heck, Conti's $325 apiece Olympic handmade track tubulars now come with buyl tubes. Makes a guy sorta lazy.
Now you might have a slow leak, but if it's in a new tire, try tightening the valve core in the stem or even replacing it before looking for problems elsewhere. Often tires get shipped without the valve tightened, or a bit of rubber junk gets caught in the seal and prevents it from working properly. If you're seeing a really big pressure drop, check the value core and see if it makes things better.
More and more tubular manufacturers are going with ultrathin butyl rubber (black rubber) tubes, which don't lose air anywhere near as much (it takes a week or two to lose that same 15-20 psi). Butyl tubes used to be thick, heavy, and killed the good ride, causing them to be found only on cheap tubulars. Now the ultrathin ones are comparable in weight to latex, and by being so thin are much more supple as well. Consequently you see them in a variety of really nice tires. Heck, Conti's $325 apiece Olympic handmade track tubulars now come with buyl tubes. Makes a guy sorta lazy.
Now you might have a slow leak, but if it's in a new tire, try tightening the valve core in the stem or even replacing it before looking for problems elsewhere. Often tires get shipped without the valve tightened, or a bit of rubber junk gets caught in the seal and prevents it from working properly. If you're seeing a really big pressure drop, check the value core and see if it makes things better.
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my contis do [but they're old and really need replacing]
if you've got a slow puncture, you could try putting in some of tufo's sealant and seeing if that stops it.
fsnl
sparky
if you've got a slow puncture, you could try putting in some of tufo's sealant and seeing if that stops it.
fsnl
sparky
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Oops. Sorry, I didn't notice the tires you were describing. They lose pressure just like other tubular tires, albeit fairly slowly. The Tufo sealant works well at low pressures, but at track pressures it tends to blow out or just not hold the high pressure. I've given up on it for this application. Do check the valve stem because I've had that problem with Tufos before.
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I've run into the same issue with my Vittoria Pista tubulars, but I just assumed they used latex tubes.
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put a little dish soap around valve where it screws into the stem, if you see a little bubbling then you have found your problem. Had the same thing happen. Tightened it up and it is fine now.
Kenal0
Kenal0
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Thanks guys, I've tried looking for a leak around the tire but can't seem to find any... so yeah, like everyone suggested I think it might be the valve screw too... but I've tightened that already (finger tight) last week. Will try the soap test later tonight.
And on the subject of replacing the valve core... ah... Ceya, how is that done exactly? Thanks again.
And on the subject of replacing the valve core... ah... Ceya, how is that done exactly? Thanks again.
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That is the part you are screwing in. Look at the valve if it had flat sides you can screw it off. I will try to post pics or someone (11.4) else can by tomorrow.
S/F,
CEYA!
S/F,
CEYA!
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Originally Posted by na975
i had a tubular explode while i had my bike lying against the wall, scared the crap out of me.
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Originally Posted by Ceya
That is the part you are screwing in. Look at the valve if it had flat sides you can screw it off. I will try to post pics or someone (11.4) else can by tomorrow.
S/F,
CEYA!
S/F,
CEYA!