Valve Stem Support
 

I had a quick question... After some very spirited driving today I noticed that my valve stems are bending due to the centripetal forces until they touch the side of the rim which stops them. Is it possible to have a valve stem failure as a result of this small amount of bending?

Is it worth worrying about?

Here's what they sell to Porsche folks... don't know if they are a real mod or bogus money-making items....

http://shop.store.yahoo.com/parkplac...alstemsup.html

Brian

Yes, possible. Unlikely, but then again racing is an excellent way of making unlikely failures happen.

It's also possible for the rotating forces to cause the schrader valve to depress and leak. (At HIGH speeds)

If you want to be super anal retentive, just get the locknut-style valve stems. I don't know if they will work on non-steel wheels, however.

That happens on my Trans Am back when I was doing OT with it, I had 2 mysterious flats all due to the valve stem ripping/tearing.. Didn't think that rotating forces could cause it, but there you go..

Never had an issue with the RX-7 though.

(edit: And in both cases the leaks weren't catastrophic, the car was obviously handling funny but I brought it in quickly..)

PaulC

My Volks came with metal valve stems. As peejay described, the main body of the valve is inserted from the inside of the rim, and secured by a nut and a locknut that are on the exposed side of the rim lip. A rubber gasket seals the stem body to the rim. I doubt that these stems are going to bend or leak at street or track speeds.

I don't know whether the Volk stems will fit any other rims, but they are available for separate purchase. At least it's one more option to consider.

Regarding schrader valves leaking, a valve cap with a gasket inside may help. The Volk stems came with some nice lightweight metal gasketed caps. I've seem similar metal and plastic aftermarket caps available in many places. I put some cheap plastic gasketed caps on my truck and my wife's car and noticed that the tires lose pressure more slowly.

Use metal valve stems whenever possible and use metal valve stem caps with o-rings in them.

When installed the valve stem should be nearly parallel to the road surface; this ensures that centripetal force cannot act on the schrader valve. If the wheels hold the valve so it points toward the spindle blame the wheel manufacturer. Never create problems when you can easily avoid them.

I have the same stems in my volk rims... though the nut and locknut on mine are inside the tire, not outside. I had the nifty metal caps with the rubber gasket but some worthless waste of skin stole them! And I live in a decent neighborhood too. I don't think the volk stems will work in normal wheels because the holes in the volk rims are pretty small (mine anyway... 1993 vintage GR-C) but there are companies that make the locking style for normal wheels.