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Re: Very slow leak w Tubulars/Concern for IM? [LarryCalifornia]
[ In reply to ]
If you have Vittorias on the bike, that's not a leak, it's the latex tubes losing air over time. Unlike butyl tubes, latex tubes will gradually lose air over several days and become flat. That's the tradeoff for their lighter weight and greater elasticity (which theoretically translates into lower rolling resistance.)
MH
Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
MH
Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
Re: Very slow leak w Tubulars/Concern for IM? [LarryCalifornia]
[ In reply to ]
I posted a similar question a few weeks ago on this forum (Loss of Tire Pressure, April 28, 2003). Check out the responses there. On Saturday I did Gulf Coast Triathlon after inflating the tires on Friday evening. No problems with loss of pressure over the night or during the race.
Once, I was fast. But I got over it.
Once, I was fast. But I got over it.
Re: Very slow leak w Tubulars/Concern for IM? [LarryCalifornia]
[ In reply to ]
I gave up on vittoria tires a long time ago - the tubeless tires often have leaky valve stems. They will replace them under warrantee but that does not help you when it happens in a race.
Re: Very slow leak w Tubulars/Concern for IM? [M.S.kansan]
[ In reply to ]
I have Corsa CX on all my racing wheels. If I put them to 135lbs at 8pm - by 8am they are at 50 some odd PSI. That is with any of them, new, old, what ever. What I have found is that many times the extenders will cause a slow leak. So, to resolve that issue - I never leave the extender on while I am riding. I just take it off and put it in my bag. I also have one duct taped to the bottom of my seat, no matter what I know I have one with me.
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What if the Hokey Pokey is what it is all about?
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What if the Hokey Pokey is what it is all about?
Re: Very slow leak w Tubulars/Concern for IM? [Record9ti]
[ In reply to ]
Why don't you put the tire under watter and see if it is the extender leaking. Use the sink or bathtub or a big bucket. That will set your mind at ease if you know it isn't leeking.
Dirtball
Dirtball
Re: Very slow leak w Tubulars/Concern for IM? [Record9ti]
[ In reply to ]
and i quote (from myself):
"On at least two occasions I've experienced slow leaks that were not slow leaks at all, upon inspection. I thought they were slow leaks -- i.e., I thought I'd run over something sharp -- and in both cases this resulted in my changing the tires, just to subsequently discover that the leaks were in my valve stem or valve core. All racing bikes nowadays come with presta valves, which -- unlike Schrader valves, and are what comes on your car's tires -- are made in two types. One has the valve core built into the valve. The other has the core as a separate piece which threads into the valve.
"There is no advantage one to the other, except if you need to use a valve extender, assuming the extender you choose is the kind in which you unscrew the valve core from the valve, thread in the extender, and replace the core in the end of the extender. You can only do this with the sort of valve that uses a replaceable core. I like this kind of extender, by the way, for reasons outlined below. But if you use a long-valve tube or tire for your deep-dish rim you won't need an extender (unless, perhaps, for a really deep rim, like a Hed Deep).
"You can have two problems with valve stems. First, sometimes the core isn't threaded into the valve stem tight enough at the factory. So, when I race, I make sure my race wheels have the core reasonably tight. There is a kind of spoke wrench that is about the size of a silver dollar, with slots around its perimeter in different gauge sizes. One of the slots -- the largest as I recall -- is 11-gauge. I've never seen an 11-gauge spoke, but it just so happens this is the exact diameter you need to engage the flats on the valve core. But be careful not to just start tightening the thing down, because you'll peel the valve right out of the tube. You've got to grab the valve with, say, a pair of pliers to keep it from spinning. This means two wrenches, one to grab the valve shaft, one to grab the core. (If you don't have that spoke wrench I'm talking about, a pair of mini-sized needlenose Vise Grips works nicely. Don't tighten it too much, just snug. That'll stop any chance of a slow leak here."
Full article is here, with photos attached:
http://www.slowtwitch.com/mainheadings/techctr/wheel.html
Dan Empfield
aka Slowman
"On at least two occasions I've experienced slow leaks that were not slow leaks at all, upon inspection. I thought they were slow leaks -- i.e., I thought I'd run over something sharp -- and in both cases this resulted in my changing the tires, just to subsequently discover that the leaks were in my valve stem or valve core. All racing bikes nowadays come with presta valves, which -- unlike Schrader valves, and are what comes on your car's tires -- are made in two types. One has the valve core built into the valve. The other has the core as a separate piece which threads into the valve.
"There is no advantage one to the other, except if you need to use a valve extender, assuming the extender you choose is the kind in which you unscrew the valve core from the valve, thread in the extender, and replace the core in the end of the extender. You can only do this with the sort of valve that uses a replaceable core. I like this kind of extender, by the way, for reasons outlined below. But if you use a long-valve tube or tire for your deep-dish rim you won't need an extender (unless, perhaps, for a really deep rim, like a Hed Deep).
"You can have two problems with valve stems. First, sometimes the core isn't threaded into the valve stem tight enough at the factory. So, when I race, I make sure my race wheels have the core reasonably tight. There is a kind of spoke wrench that is about the size of a silver dollar, with slots around its perimeter in different gauge sizes. One of the slots -- the largest as I recall -- is 11-gauge. I've never seen an 11-gauge spoke, but it just so happens this is the exact diameter you need to engage the flats on the valve core. But be careful not to just start tightening the thing down, because you'll peel the valve right out of the tube. You've got to grab the valve with, say, a pair of pliers to keep it from spinning. This means two wrenches, one to grab the valve shaft, one to grab the core. (If you don't have that spoke wrench I'm talking about, a pair of mini-sized needlenose Vise Grips works nicely. Don't tighten it too much, just snug. That'll stop any chance of a slow leak here."
Full article is here, with photos attached:
http://www.slowtwitch.com/mainheadings/techctr/wheel.html
Dan Empfield
aka Slowman
Re: Very slow leak w Tubulars/Concern for IM? [Slowman]
[ In reply to ]
Uhhmmm....Dan? If I read the original post correctly, this bike sat in the garage for 2 weeks, and when he checked it the tires were flat. The valve core advice is damn good info, but with semi-oxygen permeable tubes like Vittoria's have, I don't think it will make any difference - his tires will be flat after 2 weeks regardless - and it's really nothing to worry about. :0)
MH
Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
MH
Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
Re: Very slow leak w Tubulars/Concern for IM? [fredly]
[ In reply to ]
"Uhhmmm....Dan? If I read the original post correctly"
yes, that's true. could just be the latex tube. but as what might be noticed upon closer inspection, i was replying to recordt9ti, who went from 135psi to 50psi overnight, not to the original post.
this might seem like a problem for record9ti, but apart from the advice i gave him, which might fix his leaking problem, he could actually have a money-making tactic. imagine getting a spammail with the subject, "how to lose 85 pounds in 12 hours."
then you click thru and type in your credit card number, and ten bucks later you get the secret: slightly loosen your valve core.
you could likewise profit: "lose 10 pounds a day using latex."
Dan Empfield
aka Slowman
yes, that's true. could just be the latex tube. but as what might be noticed upon closer inspection, i was replying to recordt9ti, who went from 135psi to 50psi overnight, not to the original post.
this might seem like a problem for record9ti, but apart from the advice i gave him, which might fix his leaking problem, he could actually have a money-making tactic. imagine getting a spammail with the subject, "how to lose 85 pounds in 12 hours."
then you click thru and type in your credit card number, and ten bucks later you get the secret: slightly loosen your valve core.
you could likewise profit: "lose 10 pounds a day using latex."
Dan Empfield
aka Slowman
Re: Very slow leak w Tubulars/Concern for IM? [Slowman]
[ In reply to ]
Touche'
You know Dan, with these weight loss ideas, and the "alternative" wetsuit applications market, there's a goldmine out there just waiting for some enterprising tri-geek...
"Clad head-to-toe in quick release (2-piece!)neoprene, the fully-shaven BodyGlide-lubricated (insert gender here) inserted the tip of the valve-core into my latex tubular..."
MH
Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
You know Dan, with these weight loss ideas, and the "alternative" wetsuit applications market, there's a goldmine out there just waiting for some enterprising tri-geek...
"Clad head-to-toe in quick release (2-piece!)neoprene, the fully-shaven BodyGlide-lubricated (insert gender here) inserted the tip of the valve-core into my latex tubular..."
MH
Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
Be careful with the extenders - cheap ones will ruin your day. I got some of the generic extenders sold through QBP I think, they screw on to the top of the valve core itself. I was pumping up a Tufo tubular tire while it was off the bike, the tire fell over and the valve core snapped with half of it still in the tubular. I have to get a new valve core, and find some way to get the old valve core out. I have ordered up the Tufo valve extenders which are meant to be a permanent addition to the tire and will not cause the same problem that I had before. Because they are permanent, you don't have to worry about carrying the extenders around with you - along with the teflon tape...