Converting Presta rim to Schaeder?

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11-01-13 | 11:22 AM

#26

rumrunn6

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Joined: Jul 2008

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From: 25 miles northwest of Boston

Bikes: Bottecchia Sprint, GT Timberline 29r, Marin Muirwoods 29er, Trek FX Alpha 7.0

Quote:

Originally Posted by FBinNY

This is ONLY true if the adapter is too long. The right length adapter will have the top of the valve stem just below the lip of the adapter, the same way the pin on an SV is. Since adapters are brass, or aluminum, they're easy enough to file, so everyone can solve this problem (if they have it) themselves.

maybe this was the issue (adapter too long). I shud look at an old tube and the adapter. did you see the video where the guy just cuts his dust cap in half to make an adapter? pretty swift if you ask me, it was also quite short

11-02-13 | 01:11 AM

#27

Medic Zero

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Joined: Apr 2011

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From: Kherson, Ukraine

Bikes: Old steel GT's, for touring and commuting

Quote:

Originally Posted by mgb

Is it safe to use a Presta valve tube in a Schraeder rim WITHOUT the adaptor? I'm doing that right now, Presta in the rear tire and Schraeder in the front tire . I though it was probably ok since the entire Presta valve stem is metal. I'm converting to Presta so that my spare tubes will work with the other bikes I ride with.

I've done this off and on over the years for many miles with no problems. You are using the little nut to hold in place right? If you want more peace of mind there are both plastic and metal hollow shims designed to fill that space, but you should be fine.

11-02-13 | 01:13 AM

#28

Medic Zero

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Joined: Apr 2011

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From: Kherson, Ukraine

Bikes: Old steel GT's, for touring and commuting

Quote:

Originally Posted by FBinNY

yes, you said it right. PV's are simple check valves that open and close so air can enter the tube, but not flow back out.

EXCEPT

That sometime between when the Italians and French made them, and when it all went to Taiwan and China, they messed up on the gasket material so now the valves stick closed over time, and have to be unstuck by manually letting a bit of air out (burping) before they'll work right when you pump.

THAT is some valuable information! Thank you! A few of my tubes have been driving me mad, and I couldn't figure out why. It wasn't until this thread that I had ever heard of "burping" them and this information makes it all very clear.

Thanks again!

11-02-13 | 01:18 AM

#29

Medic Zero

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Joined: Apr 2011

Posts: 2,285

Likes: 1

From: Kherson, Ukraine

Bikes: Old steel GT's, for touring and commuting

Quote:

Originally Posted by rumrunn6

no I can't actually. I just know it didn't work when I really needed it to. and I tried 3 machines one desperate day. so never again will I rely on outdated technology for which there is no need. Schrader valves rule and that's my opinion!

if there is no pin to push against the gas station chuck what allows the air to leave the gas station pump/hose/chuck to fill the tire??? doesn't it have to be valve pin against pump chuck pin?

I've had similar experiences. Maddening! No of course, it wasn't operator error, when you're in such a situation, you try again and again, hoping to get it right before the pump stops running or you run out of quarters! I think I've tried every combination of how open/closed the Presta was before I screwed the adapter back on. Luckily I was able to get some air in, just not anywhere near as much as I'd think was safe. Managed to make it home without a snake bite, but was concerned the whole way, and this was at the beginning of a 50 mile ride home! O.O

Makes me tempted to explore the CO2 inflaters so I have a back-up when I'm touring. I had a scare once when my pump wouldn't work in the middle of nowhere. Turns out it had shook itself loose, and just tightening it up made it work again, thankfully!