On Sun, 1 Apr 2018 17:50:16 -0000 (UTC), Duane wrote:

I see no value in trying to get a presto tube to work in a rim made for a
schraeder tube. Seems like just asking for trouble.

What kind of trouble would you anticipate? Installing a Presta stem
in an oversized hole is certainly a bad idea. A suitable shoulder
washer should provide adequate protection.

Most of my rims are drilled for Schrader, while most of my tubes have
Presta valves. Don't ask why I got myself into this situation. I
initially used rubber grommets as adapters (because I had some).
However those eventually crumbled or devulcanized from UV or chemical
exposure.

Another advantage to using an adapter is that I can stock only Presta
style tubes, and they will fit both Presta and Schrader drilled rims.
No need to stock tubes with both types of valves.

Other adapter designs are available:
https://www.google.com/search?q=schrader+to+presta+rim+adapter&tbm=isch

I used a lathe to make a few that looked something like this:
http://wheelsmfg.com/catalogsearch/result/?q=presta+stem+savers


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558