Vittorio Corsa G+ tubular bulge at valve

Discuss light weight issues concerning road bikes & parts.
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NiFTY
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Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Got a new set of ax lightness 25T (799 grams for the set for the record). This is my first set of tubs, bought a pair of vittoria corsa G+ to mount. Have read the tubular thread and have sanded the rim bed and pre-stretched the tyres. I have noticed a bulge at the valve where it seems the excess basetape is holding the tyre off the rim at this point, it is identical on both rims and both tyres. It is easily palpable in hand but as the tyres are unglued I have not ridden it to see if it is detectable when riding but would imagine it would be, especially at speed.

Now the tyres go on super easy and are if anything overstretched so it isn't bunching at the valve. I have no glue on the rim but a huge amount of force is required to flattened out the bulge and my concern is the gluejob will be compromised by this.

Options - 1) I have read of people trimming the basetape of vittorias to alleviate this problem, but i cannot find, despite searching, any method to do this, or how much is safe to take.
2) I have also read of people enlarging the spoke hole, which i am prepared to do, but would rather avoid as it will undoubtedly void my warranty on what are brand new rims.
3) Are vittorias just shit for this issue and should i try another tubular brand.

Advise/recommendations please.
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by Weenie


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Kayrehn
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by Kayrehn

Trimming the material around the valve might ruin it as the inner tube might bulge out through the gap there upon inflation. Don't think it's a vittoria problem, I use them for years and it's ok if you mount them right - upon gluing and mounting, I inflate it 3/4 way up, put a pair of zip ties on either side of the valve, and then inflate them up all the way. That will anchor down the valve area.

RyanH
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by RyanH

I've noticed this too with the new Vittoria Corsa tires. It's very annoying. I've never had that issue with Conti or Veloflex. It's not noticeable when riding but it makes an audible sticky noise when riding slowly in quiet areas (like the hallway).
Strava
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beanbiken
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by beanbiken

Hi Nifty, similar scenario here with my 25T's and Corsa CX's. I did actually trim a little of the base tape from around the valves and from memory had everything nice but for the valve area so I clamped the area overnight with a pair of the sliding type clamps with the rubber feet/pads. Worked a charm but would expect the zippy tie idea to be just as good. You are also likely to get a small bump where the base tape overlaps itself.....

Steve
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MJB
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Joined: Thu Jan 19, 2012 11:17 am
Location: bottom edge of Australia

by MJB

I've mounted maybe 6-7 pairs of Vittoria tubulars.

3) Are vittorias just shit for this issue and should i try another tubular brand.


No they are a perfectly good brand. FMB is a great brand of tubular- they bulge at the valve more than Vittoria do........... doesn't stop me from using either brand happily.

I simply take a fresh scalpel blade to the cloth tape around the valve, typically 2-3mm out from the valve stem all around - makes a neater mount.

This is not a biggie - you'd have to be a true oaf to cut too deep and nick the inner tube. I like the zip tie idea whilst curing the glue. :idea:

dcaspira
Posts: 27
Joined: Sat Jul 14, 2012 1:10 am

by dcaspira

Kayrehn wrote:Trimming the material around the valve might ruin it as the inner tube might bulge out through the gap there upon inflation. Don't think it's a vittoria problem, I use them for years and it's ok if you mount them right - upon gluing and mounting, I inflate it 3/4 way up, put a pair of zip ties on either side of the valve, and then inflate them up all the way. That will anchor down the valve area.

+1 to Zip Ties. :D

joejack951
Posts: 386
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

Had the same issue with these tires. I resolved it by slightly enlarging the valve hole in my rims. Going from 8.5mm to 9.25mm made all the difference. No warranty worries on my open mold rims, though. However, I'd have a hard time believing AX would give a shit about you enlarging the hole unless you somehow managed to make the rim fail at that exact spot.

sungod
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by sungod

i never notice the bulge riding, but the first time i mounted them i got a slight 'tick' each revolution as the bulge had forced the basetape away from the rim, it was really annoying

in the end i removed and remounted using a lot of force on the valve area and pulling the tub as tight as i could manage for the first half (it meant the rest on the tub went on so easily i actually wondered if it'd be too loose)

this eliminated the problem

they are really nice to ride, wet grip is good but they cut even more easily than veloflex, i won't get them again as wet uk roads kill them fast

by Weenie


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