spectastic

I got 2 new vittoria corsa tubulars. one of them had a bad valve core (no big deal). but both of them leak at the valve stem, indicated by under water tests at 60 psi. I got them online from a reputable retailer based in the UK is this an easy fix or am I going to have to do some work?

I got 3 weeks till next big race, but really 2 if I want to make sure I glue them right

I <3 Robots

Make sure they are tight?

Take them off and check if the black o-ring is there.

They the Evo CX II?

spectastic

what do you mean? no I don't mean the valve core, I mean the valve stem base

2013 Vittoria Corsa CX Tubular Road Tyre


OH AND THIS IS REALLY WEIRD. WHEN I PUMP UP THE TIRE, I'D HEAR HISSING NOISES FOR A SHORT PERIOD OF TIME, AND THEN THE HISSING WOULD STOP, AND I COULD KEEP ON PUMPING. THE HISSING NOISE IS COMING FROM THE BASE OF THE VALVE STEM AS WELL, BECAUSE THE HISSING GETS MUFFLED WHEN I PUT MY FINGER ON TOP OF IT. THE LEAK YOU SEE IN THE PICTURE IS WORSE ON ONE OF THE TIRE, BUT THE HISSING OCCURS JUST THE SAME ON BOTH TIRES. WHERE'S THE HISSING COMING FROM AND WHY DOES IT STOP???

gsa103

Its possible that its not fully glued at the stem. When seated in a rim the pressure against the rim wall would help form a better seal. You could mount in on a rim with no glue and see if it held pressure for 3-4 days.

spectastic

ok that helps. I'll leave it at around 130 psi for a few days and stretch it out. meanwhile, I'll wait to see what the seller has to say about this


btw. the grip on my low end pump busts at pressures of over 140 psi. any suggestions for a good valued pump that covers all practical purposes??

Psimet2001 

The reason it mattered is that the EVO CX II had a different valve design that would lend itself to leaking at that junction, but was easily fixed. What you have is an EVO CX III. Many times a tubular valve can leak when first being put under pressure - even at the base, etc. Usually stops as soon as it sits under pressure.

If yours is still leaking then you have a cut/tear at the base. Happens if there is too much handling on the valve, etc while in transit. If it hasn't been glued then most distributors will take it back for an exchange. I'f you've glued it or otherwise altered it then sorry.

If it's yours and you're not going to be able to exchange it then run a bit of cafe latex sealant into the tube. Should seal it right up.

spectastic

ok it's been almost 24 hours, and both tubes went from 130 down to 60. I'm not positive it's 60, but the're definitely soft. i've never worked with latex tubes, but I doubt they're supposed to leak this fast..

Thirstyman

for the past 5 years I have noticed that my veloflex latex tubulars drop from 120 to 90 in 24 hrs.

gator58

Had this prob once. Very small leak in another location. The air traveled around the inside of the casing, coming out at the stem.love tubies

Homebrew01

I would want a refund/replacement

max5480

For the record I have this same problem with the same tire (don't know if it's the evo CX II or III). So I replaced it with a different tire and use the EVO as a spare. Funny thing is, the new tire also has a slow leak at the valve connection. Thankfully I only need to pump it up every two weeks or so, but it's still a nuisance. I've never had a flat with a tubular, just valve problems. Maybe I'm doing something wrong, but after lots of googling I don't know what it could be.

surgeonstone

Replace it.

Fred Smedley

I would dry install on a rim , if air is still leaking in a hour I would send them back. It's a good thing to check your tubulars before gluing.

spectastic

i sent those back and got a new pair of the same tubes. these have the valve stem unscrew at the base. I tightened them as far as I thought was reasonable, but I still get a few bubbles, though not nearly as much as the previous pair. it happens when i pluck thhe stem to one side. I'm guessing this isn't a big deal, and that I can just seal it up with a few dabs of tubular glue?