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Conference noted::bicycle

Title: Bicycling
Notice:Bicycling for Fun
Moderator:JAMIN::WASSER
Created:Mon Apr 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3214
Total number of notes:31946

387.0. "enlarge valve stem hole in rim, safely?" by LEDS3::LIPSON () Thu Jul 09 1987 21:00

Can you "enlarge" the valve stem hole in an alloy rim without damaging the
wheel?  I've got a prebuilt alloy wheel with a valve stem hole sized
for presta and the tubes/pump I use are Schrader [think I got that right].

	Can I use the proper size drill,  or a reamer to make the hole
large enough,  or should I get a wheel with the proper sized hole?
[What IS the proper size drill?  I would certainly be careful to file down
any burrs that might be left.]

	I recall reading in a bicycle catalog under a description for
a reamer "perfect for enlarging the valve stem hole" -- is this commonly
done,  or is it "bad advice"?
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387.1should not be any problemNOVA::FISHERP-B-P qualifiedFri Jul 10 1987 07:514
    I've seen it suggested/advised for years and never seen a conflicting
    statement.  I think it's done quite often.
    
    ed
387.2TALLIS::JBELLWot's..Uh the Deal?Fri Jul 10 1987 09:5312
	I've done it and it worked OK.  I don't think that it would work on a
	narrow rim, but mine was a wolber 58 (moderately wide).

	I think that the proper size is 3/8 inches.

	The alternative, of course, is just to use a presta tube.  Most
	schr�der bike pumps can be converted to presta, and you could change
	the other wheel to presta with one of those grommets.


	-Jeff Bell
387.3One Negative ExperienceAQUA::ROSTThe old fart was breathing freelyFri Jul 10 1987 11:2118
    
    Just be careful. 
    
    I had a bike that I bought where this was done without my 
    knowledge (aparently they didn't want to bother building
    up Schrader rims for me) and after about a year's use I started
    getting punctures next to the valve approximately every day.  One
    day trip I went through five tubes.
    
    After every shop I went to feigned ignorance of the problem, someone
    suggested replacing the rim with one drilled at the factory for
    Schrader....voila! no more flats.
    
    If the hole is too large you will have this sort of problem.
    
    
    
    
387.4Stick with your Presta'sELWOOD::FUSCOTue Jul 14 1987 16:286
    My advice is to stick with the Presta hole and buy new inner tubes.
    There are screw on adapters if you are ever forced to use a compressor,
    and the pumps work better with Presta, losing no air when you remove
    it, and it decreases the chance of breaking off the valve stem.  
    Schraders are great for 30 psi car tires, but the Prestas are common
    on bicycles for a lot of good reasons.
387.5using Presta tubes in a Schrader wheelCLT::ZEHNGUTFri Sep 30 1988 13:3810
    I've got the opposite problem, that is, I've got Wolber 58 wheels which
    are driiled for Schrader valves and I want to use Presta tubes.   The
    hole in the wheel is too big, and I've already blown a couple of tubes
    because of this.  Is there an adapter I can insert into the hole to
    allow me to use Presta tubes?  What's the best way to fix this, without
    buying new wheels?
    
    Thanks for any advice.
    
    Marc
387.6I have seen a solution offeredCURIE::WAGNERFri Sep 30 1988 14:129
    RE: -.1
    
    Some time back, when Presta stemmed tubes were just beginning to
    become popular, a bike shop I visited had rubber grommets which
    would fit within a Schraeder sized stem hole.  You might be able
    to find some of the right size at an electronics supply house -
    maybe even Radio Shack.
    
    Jim