corkscrew

My recent purchase (C'dale t700) came with 700C ritchey "rock" rims, but they are oddly drilled for Shrader valves.

I'd like to run presta valves as personal preference - can I simply swap tubes or is this a bad idea with the larger Shrader drilling?

jco1385

get a grommet: https://www.google.com/products?hl=en...ed=0CCYQrQQwAg

X-LinkedRider

You can use the Presta valves due to the size, however it is HIGHLY not recommended. Because the hole is larger it leaves much more room for the tube or valve seem to come sticking through the rest of the opening in the hole.It will work, but It's not worth the random flats or tire explodes.

operator

+1

Run those if you're doing what you plan on doing. Otherwise just get the correct tube.

corkscrew

Thanks guys. I'll call down to my LBS and see if they have those grommets.

DieselDan

One stopgap trick is to put the stem nut inside the rim to prevent the tube from bulging out.

corkscrew

I plan on using this bike for touring, so I'd rather just do it correctly.

Have a set of these en route. https://www.amazon.com/exec/obidos/tg...28WSA&v=glance - figure they will hold up better then a rubber grommet.

I'll replace the tubes when they eventually can't be patched anymore. I prefer shrader valves on my vehicles, not my bicycles.

X-LinkedRider

Good and quick you are with the purchasing. I am the same way. The rubber is nice for ease of installation and of course there can never be a sharp edge. But let us know how these metal ones work out. For a couple dollars what is the harm in trying everything out there you know.?

AdamDZ

Yeah, I used the aluminum ones for years, no problems, I think they're called Presta Savers.

Adam

corkscrew

I noticed they are made by Wheels Manufacturing, whom I've heard good things about. Figure they would be worth a shot for a few bucks, and didn't want to deal with replacing worn rubber grommets if one fails on tour. Might need to grab some new rim tape since they suggest installing these under the tape. Velox is cheap at the LBS though.

mrrabbit 

Grab a box of 6 1/4" grommets from Gardner Bender? (GB in the electrical industry....) They'll be in a clear with red label plastic package at your local Orchards, Payless Hardware, Home Depot, etc.

They look like the classic Cyclon base ship - not the "reimagined" one.

On a circle on one side, snip off the edges of the circle in parallel...so you have two parallel opposing edges that are straight and two opposing edges that are curved.

Pop in, ready to go. Plus you'll have 5 extra all for the same money you would pay for 1 at an LBS.

=8-)

jco1385

fwiw, velox is pretty good tape. i'd just peel it up, install the 'grommet' and put it back down. i see no need in replacing it.

gamecock

In a touring sense, I believe rims drilled for Shrader with the inserts and Presta valves are at an advantage because either tube will work, and I can use whatever is available--even though that is more likely to be Shrader.

corkscrew

Really? I've had more luck finding 700C tubes in Presta - at least @ the LBS and online. 26" tubes on the other hand are much more common in Shrader. That is a good point about either working though.

On the tape I'll check what shape the existing stuff is when I get these adapters. Being a new (to me) bike I haven't had to remove the tires yet, but have the valve adapters and new tires en route, so I'll be in there soon enough.

jco1385

if you need a 700c tube with a schrader, you can sub in a 27" tube. they most always have the schrader. i was in the opposite situation last weekend. needed a 700c presta and only had a 27" schrader.

phoebeisis

In a pinch I just put a few wraps of rim tape-(bought a couple of big rolls years ago) around the stem-works ok. I usually have to split it down the middle because it is kinda wide. Grommet is nicer of course.

layedback1

The rims on my Rans Stratus are drilled for schrader tubes. However the bike came with the aluminium "grometts"and presta tubes. They have worked fine for 5 years. I might add that it does give you an option when touring in a pinch you can use either.

DieselDan

Look at this way: You can always find 27" tubes with scharder valves just about anywhere, but not presta valves. If you look at the size stamping on a 27" tube, most of the time it is co-labeled as 700c. If your ever out touring and you need a tube in a little town that only has a hardware store, chances are they will have a 27" scharder tube. With those rims, you can just pop out the grommet and install the new tube and continue enjoying your ride.

Like layedback1 said.

corkscrew

I didn't consider the Shrader 27" tubes, but all my 27" bikes run presta valves currently.

dprayvd

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dprayvd

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DVC45

Sorry to jump-in late and for a noob question, but, does drilling a presta rim to accept Schraeder tubes weakens the rim?
I like the idea of drilling to beable to use both tubes, but I don't want a weakend rim either.

Thanks in advance!

Dan The Man

I had this exact problem. Luckily the hardware store also sold chainsaw files. It took me 15 minutes to "adapt" my Alex rims to fit a Schraeder tube.

corkscrew

So those nifty aluminum adapters arrived today. They don't fit! They drop straight through the valve's opening in the rim. They don't LOOK drilled but I'm beginning to wonder. Ugh, so much for that theory.

JiveTurkey

The adapter goes straight through? The valve hole is really two holes, one near the tube, the other facing the center of the wheel. Does the adapter slide through both holes?

If it only goes through one of them, slide it first through the smaller hole. If the smaller hole is the one nearer the center of the wheel, you'll need to also use the valve's nut to hold it in place. (Edit: However, if your rim is not very aero, then the adapter might be so long it sticks in past the rim tape, in which case it could damage the tube.)