Brad W

Has anyone used a rubber grommet to reduce a schrader hole to fit a presta valve? I've see fancy metal reducers but I thought I could do something on the cheap. It's just a single wall alloy rim.

Brad

jsharr

Never used one, but there are tons out there. Google presta to schrader grommet. Lick bike has one for $.60

well biked

Yes, I've used them. I prefer them to the aluminum sleeve-type adapters, which I've used also.

fuzz2050

You don't really need anything, just bring a spare tube for when your valve stem rips off.

dabac

Ripping a valve stem off has considerably more to do with the tire slipping on the rim than with how the valve fits in the rim. Or, possibly due to clumsy pump work.
I've ridden countless hours and miles with supposedly mismatched valve stems and rim holes w/o any troubles, and I've ripped several stems straight off in supposedly matched configurations due to tires slipping.
Once I've seen some potential for trouble due to stem/hole mismatch, there was some chafing on the rubber around the stem. That was easily avoided by cutting a patch out of a discarded tube, punching a hole in the patch and threading the patch over the stem before inserting the stem in the rim.

bbd

A little while back Mavic had a small rubber grommet that they used to place in their rims so you had the choice of either running presta or shraeder valves. I have seen a few around as i am the tech guy for Mavic in Australia. Maybe some of your local dealers could track a couple down for you.

dabac

And, as I recall, the fitting instructions stated that the grommet should be placed in the inside wall (closest to the hub) of the rim. It does a semi-decent job of preventing water intrusion into the rim, but it doesn't do squat for reducing stress on the valve stem.

leob1

Valve stem failure can also be caused by a burr around the valve stem hole. It slowly chews the rubber. Popping of a stem is definitly an "OH CRAP" moment.

Brad W

Since Well Bike has used them that's good enough for me. I'll give them a try.

Brad

jsharr

I have always wondered about making an adapter out of an old schrader valve tube. Remove the valve core. Cut the stem off so it is just tall enough to clear your rim when inserted from inside. Then cut the valve out of the tube. Now insert the surgically removed and altered valve in your shchrader valve rim and install your presta tube. The only sticking point is if a presta valve would go through a schrader stem. Not sure of this.

triplebutted

When I was at the hardware store getting parts for the Sheldon BB tool thingy, I rummaged through the drawer of "grommets" and I thought "this is exactly the stuff they sell for schraeder to presta!". But I didn't know the exact size of the schraeder hole so I didn't get any. But it was a heck of a lot cheaper than places like "loosescrews.com".

JTGraphics

I have used both the rubber and the aluminum presta adapters on my Hybrid 700c and a 26" rim.
The aluminum adapters will work on any rim the rubber grommet style will not work on some rims because the groove (best with flatter style rims) in it may not be wide enough to fit correctly thats something I ran into with my rims the Hybrid 700c needed the aluminum style the rubber one would not fit correctly and the 26" rim used the rubber the aluminum stuck out to far on the inside which in the long run would of damaged the tube.