Motorports folks... tell me about VALVE STEMS.

bdubblu · 11-26-2019, 05:30 PM

I hate to post this in general, but the motorsports thread has no activity.

I'm seeing that the faster cars are required to have metal valve stems on them. Not sure if this applies only to drag racing, or if there are any circuit regulations that are similar. But I'm going to get them regardless. What I want to know is if there are any types to steer clear of? I see a couple different styles.

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kos · 11-26-2019, 05:40 PM

Required? Depends on the series or discipline of driving.

I haven't bought aftermarket solid stems, the wheels I have purchased came with them (Advan, RAYS, etc)

willowlee · 11-26-2019, 06:40 PM

Not related, but don't the tpms light up when you used metal stem? Something about the metal ones that only have one port. I was forced to use the rubber ones off my oem wheels when i put my volks wheels on. It came with metal stems, but the tire shop tech say he cannot use the metal ones. Don't know if he's bulll****ting me?

MedicMoses · 11-26-2019, 07:43 PM

The metal ones on my Sparos were not compatable. Dealer did the swap for me, they showed me that the ones on the Sparcos didn't have the threaded part for the TPMS sensors.

bdubblu · 11-27-2019, 11:46 AM

Quote:

Originally Posted by kos

Required? Depends on the series or discipline of driving.

I haven't bought aftermarket solid stems, the wheels I have purchased came with them (Advan, RAYS, etc)

I believe most drag strips require them for cars in the 11's. And yes, I agree it might be dependent on the sanctioning body, but that's why I stated all this in my original post.

bdubblu · 11-27-2019, 11:47 AM

SO... back to my question. Does anyone have any particular reason I should use one style or another for metal valve stems? I just want to stay away from designs that may be flawed.

jack hidley · 12-03-2019, 01:42 PM

Metal valve stems are not legal for use in any race series that is likely to ever have wheel to wheel contact. If there is ever tire to rim contact, the valve stem either breaks off or gets instantly pulled out of the rim, which results in instant tire deflation.

NHRA requires screw in metal valve stems in cars running 11.99 or quicker, if the car doesn't have a functioning OEM TPMS. There is absolutely nothing wrong with using rubber valve stems at moderately high speeds. The problem here is that most drag racers are really cheap and won't have the valve stems replaced when they replace their tires, so the rubber gets old and cracks, which can then fail.

If your rubber valve stems are replaced at normal intervals (when you install new tires). There is no reason to use metal valve stems.

Most threaded metal valve stems will require the stem hole in the wheel to be drilled out larger. This will keep you from going back to rubber stems in the future.

Jedi03 · 12-03-2019, 06:54 PM

saw the metal ones on trucks when working on them...were pain for the most part but nice for dual axles when they poke through to the outside for checking air...

WhiteZombie · 12-03-2019, 07:42 PM

What motorsport discipline?

Twisty turny stuff, rubber is just fine and likely the better choice for their flexibility. Rubber on my track car for almost 10 years, no issues. They get replaced with each set of new tires, so 2 seasons with maybe 5-10 events usually.

My buddy did a little blog post on it:
https://nomoneymotorsports.com/2019/...-wrong-choice/

For drag racing I have no clue, so definitely listen to the other guys!

bdubblu · 12-05-2019, 09:15 AM

Quote:

Originally Posted by jack hidley

Metal valve stems are not legal for use in any race series that is likely to ever have wheel to wheel contact. If there is ever tire to rim contact, the valve stem either breaks off or gets instantly pulled out of the rim, which results in instant tire deflation.

NHRA requires screw in metal valve stems in cars running 11.99 or quicker, if the car doesn't have a functioning OEM TPMS. There is absolutely nothing wrong with using rubber valve stems at moderately high speeds. The problem here is that most drag racers are really cheap and won't have the valve stems replaced when they replace their tires, so the rubber gets old and cracks, which can then fail.

If your rubber valve stems are replaced at normal intervals (when you install new tires). There is no reason to use metal valve stems.

Most threaded metal valve stems will require the stem hole in the wheel to be drilled out larger. This will keep you from going back to rubber stems in the future.

I think the metal stems have more to do with rotation speeds. I was just scanning more and they are required when the tire is tubeless. Sounds like the simple bead of the rubber stem isn’t enough to keep it in place... and between the tire pressure and centrifugal force, the stems pop out.

That’s what I had originally assumed, but was wondering if it was also like an SCCA thing also.

11-26-2019, 05:30 PM	#1
bdubblu Scooby Specialist Member#: 251046 Join Date: Jul 2010 Chapter/Region: MAIC Location: Mostly at my home Vehicle: 2004 WRX Wagon Stage 5.1.2a.2	Motorports folks... tell me about VALVE STEMS. I hate to post this in general, but the motorsports thread has no activity. I'm seeing that the faster cars are required to have metal valve stems on them. Not sure if this applies only to drag racing, or if there are any circuit regulations that are similar. But I'm going to get them regardless. What I want to know is if there are any types to steer clear of? I see a couple different styles. * Registered users of the site do not see these ads.

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11-26-2019, 05:40 PM	#2
kos Scooby Specialist Member#: 118334 Join Date: Jun 2006 Chapter/Region: SWIC Location: Global Time Attack Street AWD Vehicle: 2006 Red GDB-F 2005 Aspen White GDB-E	Required? Depends on the series or discipline of driving. I haven't bought aftermarket solid stems, the wheels I have purchased came with them (Advan, RAYS, etc)

11-26-2019, 06:40 PM	#3
willowlee Scooby Newbie Member#: 358533 Join Date: Jun 2013 Location: central california Vehicle: 2013 sti sedan wrb	Not related, but don't the tpms light up when you used metal stem? Something about the metal ones that only have one port. I was forced to use the rubber ones off my oem wheels when i put my volks wheels on. It came with metal stems, but the tire shop tech say he cannot use the metal ones. Don't know if he's bulll****ting me?

11-26-2019, 07:43 PM	#4
MedicMoses Scooby Newbie Member#: 470679 Join Date: Jul 2017 Chapter/Region: MWSOC Location: Michigan Vehicle: 2018 WRX Pure Red	The metal ones on my Sparos were not compatable. Dealer did the swap for me, they showed me that the ones on the Sparcos didn't have the threaded part for the TPMS sensors.

11-27-2019, 11:47 AM	#6
bdubblu Scooby Specialist Member#: 251046 Join Date: Jul 2010 Chapter/Region: MAIC Location: Mostly at my home Vehicle: 2004 WRX Wagon Stage 5.1.2a.2	SO... back to my question. Does anyone have any particular reason I should use one style or another for metal valve stems? I just want to stay away from designs that may be flawed.

12-03-2019, 01:42 PM	#7
jack hidley Scooby Newbie Member#: 22506 Join Date: Aug 2002 Location: Danville Vehicle: 2003 WRX Blaaaaack	Metal valve stems are not legal for use in any race series that is likely to ever have wheel to wheel contact. If there is ever tire to rim contact, the valve stem either breaks off or gets instantly pulled out of the rim, which results in instant tire deflation. NHRA requires screw in metal valve stems in cars running 11.99 or quicker, if the car doesn't have a functioning OEM TPMS. There is absolutely nothing wrong with using rubber valve stems at moderately high speeds. The problem here is that most drag racers are really cheap and won't have the valve stems replaced when they replace their tires, so the rubber gets old and cracks, which can then fail. If your rubber valve stems are replaced at normal intervals (when you install new tires). There is no reason to use metal valve stems. Most threaded metal valve stems will require the stem hole in the wheel to be drilled out larger. This will keep you from going back to rubber stems in the future.

12-03-2019, 06:54 PM	#8
Jedi03 Scooby Newbie Member#: 491095 Join Date: Sep 2018 Chapter/Region: SWIC Location: New Mexico Vehicle: 2009 STi Blue Blue	saw the metal ones on trucks when working on them...were pain for the most part but nice for dual axles when they poke through to the outside for checking air...

12-03-2019, 07:42 PM	#9
WhiteZombie Scooby Newbie Member#: 338863 Join Date: Nov 2012 Location: Bethlehem,PA Vehicle: PSM 05 WRX WGN 5MT 95 Caprice 6spd Track Rat	What motorsport discipline? Twisty turny stuff, rubber is just fine and likely the better choice for their flexibility. Rubber on my track car for almost 10 years, no issues. They get replaced with each set of new tires, so 2 seasons with maybe 5-10 events usually. My buddy did a little blog post on it: https://nomoneymotorsports.com/2019/...-wrong-choice/ For drag racing I have no clue, so definitely listen to the other guys!