NHRDA/NHRA rule about metal valve stem in trucks running 11.99 and faster

SmokeShow

Well-known member
Nov 30, 2006
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Lawrenceburg, KY
I'm sure there is a valid reason for requiring metal valve stems, but in what way are the rubber ones susceptible to failing while racing?
 

McRat

Diesel Hotrodder
Aug 2, 2006
11,249
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Norco CA
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Lots of orgs ban rubber stems for high speed racing, NHRA, SCTA, SCCA, Silver State, etc.

They can crack where you can't see the crack in tech. The centripetal force on some wheels will flex the valve stem, which can then break the seal. Debris/guardrails can also damage them easier in a crash.

Yes, it is a PITA, but we have been using metal on all our cars/trucks for 15 years just to avoid tech issues.
 

COMP461

Diesel Pro
Apr 29, 2008
429
0
0
Aledo Texas
rule are rules , and everyone is written in blood. NHRA didn't just make it up to annoy you, or keep you from racing, They made them to keep you safe
 

DMAXchris

It’s only temporary!
Apr 28, 2009
2,273
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Natrona Heights PA
Okay.....so why the selective enforcement? I've never had a tech check for driveshaft hoops but they're worried about valve stems? :rofl: Doesn't look like the nhrda cares about exhaust pointing up either. I think I'll stick to test n tune at the local track. It's becoming a pain the in the ass to attend one or two events/year. I feel bad for the guys that never read the rules and just show up to have some fun, just to be turned away for something stupid. It may not have happened yet, but if they are giving warnings now, there will be a point when racers are not allowed to compete.
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
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Okay.....so why the selective enforcement? I've never had a tech check for driveshaft hoops but they're worried about valve stems? :rofl: Doesn't look like the nhrda cares about exhaust pointing up either. I think I'll stick to test n tune at the local track. It's becoming a pain the in the ass to attend one or two events/year. I feel bad for the guys that never read the rules and just show up to have some fun, just to be turned away for something stupid. It may not have happened yet, but if they are giving warnings now, there will be a point when racers are not allowed to compete.

It's pretty easy to find a copy of the NHRA rules online. As for why they don't enforce them all, I can't tell you, but I can tell you I have been checked for driveshaft loops. If you don't run full slicks and don't run faster than 11.5, you don't have to have hoops.

FYI, here is the valve stem rule:

5:1 TIRES
Tires will be visually checked for condition, pressure, etc. and must
be considered free of defects by the technical inspector prior to any
run. All street tires must have a minimum of 1/16-inch tread depth.
Temporary spares, space saver spares, farm implement or trailer
tires prohibited. Metal, screw-in valve stems mandatory in tubeless
tires, front and rear, on vehicles running 11.99 or quicker.
 

sickdiesel

New member
Apr 22, 2010
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NHRDA has been great in the past for giving warnings about things, if it is your first time, but can get stricter if you dont correct it for the next race. Although this year, it seems they will be a bit more strict and for good reason IMO. Although at bakersfield they didnt check anything, i still come 100% legal, but they didnt check for trans blanket, driveline loops, locking trans dipstick, metal valve stems, etc. Which does get frustrating to me, because i spend quite a bit of time and money to be legal, while people who dont have anything close to legal are OKed to race.
 

COMP461

Diesel Pro
Apr 29, 2008
429
0
0
Aledo Texas
NHRA or IHRA has control of the tracks , NHRDA is now an ASO of NHRA and is being compelled to enforce the rules. This is due to the fact they use NHRA's insurance.

The fact that they are now running NHRA Pro Mods at their events will step up the game quite a bit . This is the down side to not being a diesel only event.

Most Tech guys use common sense , and I say most. They will give you a chance to fix it at the track or next time. this is if its not a serious ding.

once you get to the faster classes , there is no leeway .

remember this tech guys are usually volunteer , so go easy on your frustrations with them.

I have been involved with organized drag racing for 30 + years , and see this a lot more in the diesel ranks , because diesels don't race that often . go to a local bracket track and you will find it both ways ,
 

Subman

Old Geezer
Jun 27, 2008
3,233
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Madras, OR, Pahrump NV
Okay.....so why the selective enforcement? I've never had a tech check for driveshaft hoops but they're worried about valve stems? :rofl: Doesn't look like the nhrda cares about exhaust pointing up either. I think I'll stick to test n tune at the local track. It's becoming a pain the in the ass to attend one or two events/year. I feel bad for the guys that never read the rules and just show up to have some fun, just to be turned away for something stupid. It may not have happened yet, but if they are giving warnings now, there will be a point when racers are not allowed to compete.

I for one like the rules, it's not that big a deal to get metal valves stems. If the tech's know your truck you'll not be checked as closely as one that is new to them. Most of us that race a lot have turned up exhaust tips anyway, losing a race or good qualifying round because of smoked lights sucks. If you only race NHRDA on occasion then probably not worth your time to bother with it. And your local T&T is probably your best option.

I believe it was 2008, the first NHRDA race of the year there is a video of a guy in a 2x4 dodge who had moved up in class, the truck got away from him when it wasn't going that fast less than 80mph. The wreck that ensued was really something. Over the guard rail and flipping over and over and took out a power pole. The mass of these trucks going fast makes for one hell of a wreck. I won't race a truck if I know it doesn't have the correct safety equipment.
 

meshanic

All In Trucks
Dec 9, 2010
436
0
16
West Texas
The Super Diesel rules state drive line loop required. The basic NHRA rules state 11.49 or faster. I know I'm not driving 6 hours to get booted for something I read in the class rules.

Only question is on my 4wd, where do I need loops? Just the main shaft or the prop shaft too?
 

MadMooseEngineering

New member
Mar 28, 2008
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Boise, Idaho
The rear drive shaft needs a loop within 6 inches of the first u joint after the t case. The front I would assume it needs to be within 6 inches of the front u joint at the diff.
 

McRat

Diesel Hotrodder
Aug 2, 2006
11,249
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Norco CA
www.mcratracing.com
I've never seen anyone ever tech the front the front driveshaft hoop.

Casper has one, but nobody ever looked.

A front driveshaft failure is nothing like a rear driveshaft failure. It's short, and won't catapult the car in the air.

EDIT: Your results may vary. Offer not valid in Hawaii or Alaska. If you have an erection that lasts more than 4 hours, you probably just got twins on your Duramax.
 

MadMooseEngineering

New member
Mar 28, 2008
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Boise, Idaho
I have never seen them look on the front either but its better piece if mind to know if a freak accident happens its there.

I know they asked me in Bakersfield about them and I told them they aren't needed til you run drag radials or slicks and or go 11.49. I will be putting some on my truck as I will try drag radials out
 

hondarider552

Getting faster
May 28, 2008
10,627
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Arizona
Bringing this back to life instead of starting a new thread.

I will be converting my LB7 to 06 front end, but I will have to run around for a few weeks with no hood while the 06 is getting painted.


Per NHRA rule book, it states that you do not need to run a hood if you do not have a Carb. If you have a carb, you need a hood or shield around the carb base.

Has anyone ran into this, or, actually went to a TnT without a hood?
 

Fahlin Racing

New member
Aug 22, 2012
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NE Ohio
Just switch them, if you don't race because of a valve stem there is more pride on looking good that going fast without a thought. Rubber flexes metal doesn't. With flexing you have the chance to tear the stem and loose tire pressure and possibly cause a fatal accident. Picture it as a safety precaution because you cant steer worth a shit without air in your vehicles shoes unless you want to kiss the pavement on a roll over.