I have a relatively new (200ish miles) Corsa Evo CX tubular tire on my front carbon wheel used for racing. I notice when I pump it up to about 120 PSI it seems to lose most of it’s pressure by 48 hours or so later. There is no noticeable leak. How long do these tires hold air for everyone else? My concern is if I pump it up in transition before an IM, it will be less than optimal pressure by end of the bike split.
That is normal, because there is a latex tube inside.
If you pump up the morning of the IM you will only lose 1 or 2 psi during the IM leg.
Yeah, normal. I always pump in transition a couple over what I want and assume they will be spot on after the swim. They have never felt low after a race though so I don’t think they lose much/any air over the course of the race. Leave them alone for a day though and they will have less than 60psi.
Absolutely normal. Been using this tire since 2007 and never had any issues during a race. Tire will be flat in a couple days.
Thanks, I had a feeling that was the case but since I’m new to these I was looking for confirmation.
Your tire is screwed and you should just sell it to me for $20 I’ll take it away from your hands.
If you have a second one, then I’ll take that too!
(What color are the side walls?)
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yep.
also, if you have a leakily installed valve extender, that will quicken the deflation. but, normal
I think a latex tube should not lose more than 12-13 psi in 24 hours. I just add an extra 10psi to my tires the day before a race as I can’t be bothered screwing around and trying to find somewhere to store my pump on the day of a race. I recently installed 2 new CX tubies and one was losing 15psi overnight - that was a valve extender issue. So losing some air is normal, any more than 15psi per day, I would be checking the extenders for leaks. If it’s almost flat after 48 hours I would be double checking the extenders too. If I pump to 120psi I expect them to still be around 90psi a couple of days later, certainly not flat.
WHAT?! You can’t be bothered to pump up your tires the morning of a race?!
I think a latex tube should not lose more than 12-13 psi in 24 hours. I just add an extra 10psi to my tires the day before a race as I can’t be bothered screwing around and trying to find somewhere to store my pump on the day of a race. I recently installed 2 new CX tubies and one was losing 15psi overnight - that was a valve extender issue. So losing some air is normal, any more than 15psi per day, I would be checking the extenders for leaks. If it’s almost flat after 48 hours I would be double checking the extenders too. If I pump to 120psi I expect them to still be around 90psi a couple of days later, certainly not flat.
from my testing vittoria corsas and other high-end tubulars with latex tubes lose 1-2psi per hour (stationary, out of the sun). if riding them this is a bit less.
agree on checking extenders, but in my experience even with properly-installed extenders, teflon tape, etc. up to 2psi pressure loss per hour can be in the ‘normal’ range. always good for people to measure this on their own tires, especially when one is unable to inflate to their desired pressure immediately before cycling. further, if one is doing a long event, accounting for the pressure change might be something that is material depending on where the “important” part of one’s even might occur (e.g., a critical hill or a sprint in a road race).
on the positive side, most people use far too high a tire pressure, so the latex loss may get them close to the sweet-spot, inadvertently. 
It shouldn’t lose that much air in 48 hours. The CX has a red removable valve stem. Double check that it is on tight.
It shouldn’t lose that much air in 48 hours. The CX has a red removable valve stem. Double check that it is on tight.
you don’t think i’ve checked?
i’ve observed this with many tires. last year i did a test with numerous tires (6-8 if i recall), inflated to the same pressure. depending on the test, i checked them hourly, every 4 hours, or every 12 hours. i use a digital gauge (2 actually) that are consistent with one another. (this also helped me to figure out that my various pumps are off.)
i’ve also gone out on rides with a gauge and checked where things are during and after the ride. i’ve played with tire pressure and varied it from one steady-state interval to another to see what is fastest for my riding. (there were not insignificant differences.)
obsessive, for sure, but it helped me fine-tune where i want to start my pressure for my road races and TTs.
It shouldn’t lose that much air in 48 hours. The CX has a red removable valve stem. Double check that it is on tight.
you don’t think i’ve checked?
i’ve observed this with many tires. last year i did a test with numerous tires (6-8 if i recall), inflated to the same pressure. depending on the test, i checked them hourly, every 4 hours, or every 12 hours. i use a digital gauge (2 actually) that are consistent with one another. (this also helped me to figure out that my various pumps are off.)
i’ve also gone out on rides with a gauge and checked where things are during and after the ride. i’ve played with tire pressure and varied it from one steady-state interval to another to see what is fastest for my riding. (there were not insignificant differences.)
obsessive, for sure, but it helped me fine-tune where i want to start my pressure for my road races and TTs.
Just interested to know, do you lose any air from the tire in the process of checking the pressure? Any time I put a pump or gauge on the valve I always lose some air. Just asking as I just had 2 new tires, one lost about 12-13psi every 24 hours, the other was leaking twice that rate due to valve extender. Once I fixed the extender both tires held air quite well. I would be majorly concerned if a tubie was losing 24-48psi every 24 hours, that sounds excessive to me.
Anyway, back to the OP, some pressure loss is normal, excessive loss can be due to the extender. What is a “normal” pressure loss is open to debate I guess.
Just interested to know, do you lose any air from the tire in the process of checking the pressure? Any time I put a pump or gauge on the valve I always lose some air. Just asking as I just had 2 new tires, one lost about 12-13psi every 24 hours, the other was leaking twice that rate due to valve extender. Once I fixed the extender both tires held air quite well. I would be majorly concerned if a tubie was losing 24-48psi every 24 hours, that sounds excessive to me.
Anyway, back to the OP, some pressure loss is normal, excessive loss can be due to the extender. What is a “normal” pressure loss is open to debate I guess.
With proper technique I can check the same tire several times in a row an get the same reading (to the nearest 0.5psi). There is surely some loss, but it is minimal.
WHAT?! You can’t be bothered to pump up your tires the morning of a race?!
I hate pumping up my tires race morning when using a rear wheel cover and latex tubes. It takes a while, and my wheel cover is now cracked from trying to nudge the cover out of the way to get my bulky pump head on there. I probably should have just bought a crack pipe, but I never did.
It’s also a pain to pump up tires when you have to drop your bike off the day before–you’re either waiting in line to use a pump, or trying to find somewhere to put your pump.
dude, I’m so paranoid - before a crit, I’ll let my air out and repump, just to be 100% sure that temp/barometric changes haven’t changed my tire pressure!
make sure you are carrying ‘pitstop’ on your bike for flats saved my race at IM MOO last year
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make sure you are carrying ‘pitstop’ on your bike for flats saved my race at IM MOO last year
I have pittstop but I don’t know how will it will work with my Zipp valve extender on the front or the crack pipe on the rear. I’ll have my fingers crossed that I don’t have to find out.
Iran zipp 404’''s with extentors…push the tire in at the valve when you put the pit stop can on or you won’t get a good seal. once it starts filling up let loose. if you know where the leak is at put it road side down so the sealent can find the leak easier. If you do not know where the leak is at rotate the wheel slowly. have not done the crack pipe thing, but my guess you need to make an adapter becuse the crack pipe air end is not long enough to release the pitstop. I do not run a disc that often.
You are spot on with your post…