Bicycle Mechanics - Does it exist? 700 X 32C Presta Tube with 48mm Stem or Longer?

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fast_track
01-17-08, 08:39 AM
A friend of mine recently purchased a Scott SUB bike (quite cool I must say for the price) and has ended up with 2 flats in about 6 weeks. He knows nothing about bikes so I offered to fix his last flat.

He is running a set of 700 X 32C slicks on a 28mm deep Scott AERO style rim. As soon as I pulled the tube I noticed a small issue. In order to have the right amount of stem coming thru the rim, he needs at least a 48mm Presta stem. I can't find any tubes that are a fit for a 32C that have a valve stem longer that 36mm.

It looks like the bike shop that fixed his first flat a few weeks ago put a 20-28C tube in with a 48mm stem. So at 32C the tube was running thin and over inflated. I'm in NYC and called 10 bike shops yesterday and know one had a appropriate tube. I too fixed his flat for the time being with at 20-28C/48mm stem.

Don't Cyclocross riders have the potential to need a tube like this? (AKA, wider but with a longer stem)

I am getting the feeling that he is getting flats because he is riding on thin/over inflated tubes.

Any suggestions? I am thinking he might just want to drop to a 28C tire and dump the 32C's. I just know he didn't really want to put more money in the bike if he didn't have to.

Thanks in advance for any good suggestions.


Godwin
01-17-08, 08:46 AM
How about a valve extender?

fast_track
01-17-08, 08:54 AM
I can honestly say that I had no idea they even made those for presta. Just saw a few online after a quick google. Don't I feel silly? Isn't it fun to make things harder than they need to be? thanks!


flip18436572
01-17-08, 09:12 AM
I actually just got done reading a chapter in one of the bike repair manuals that talked about using valve extenders for this type of situation. I am surprised the bike shops didn't offer that as an option.

fast_track
01-17-08, 09:20 AM
I actually just got done reading a chapter in one of the bike repair manuals that talked about using valve extenders for this type of situation. I am surprised the bike shops didn't offer that as an option.

Yes, I too am surprised that not one of 10 shops was like "Dude, buy a valve extender" It's NYC. We try to make everything as hard as possible here! For $5-10 and a little extra effort at the time of inflation, it sure is cheaper than buying a new set of tires over a tube sizing issue!

supcom
01-17-08, 10:38 AM
I'm surprised the bike has aero rims. Is that stock? Seems a bit strange for a bike designed for wide tires.