Is it mandatory to have open end lug nuts at a certain ET, or running a drag radial tire on drag wheels?

 

No. The rules state that the stud must extend into the hex portion of the nut equal to the diameter of the stud. Nothing about it needing to be open ended or not.

The easiest way to understand this is if you have 12mm studs, they must extend a minimum of 12mm past the surface of the rim.

Mounting a set of Weld Drag Lite or Prostars on stock length wheel studs will not pass tech. Even though the shanked nuts grab the studs, the studs are not long enough because of the thickness of the center of the rim.

The purpose of open ended wheel nuts is for tech to see how far into the nut the studs go. You can have closed end wheel nuts but be prepared to take one off for inspection when going through tech.

 

Stephen, thanks for the reply. I'm running Bogarts, so I'll check but I think Steve (at Bogart) said I should be ok. All my metric scales are at work and I'm on vacation this week. Would you happen to know what 12mm is in inches? Thanks and by the way, I've always liked how fast you have managed to go, and how you've set your car up. Nice web page.

 

12 mm is just slightly less than 1/2". 1" = 25.4 mm, so 1/2" is actually 12.7 mm .

This is why, in some cases, you can use a 1/2" socket on either 12 or 13 mm nuts/bolts, and vice-versa, 12 or 13 mm sockets will fit on some 1/2" nuts/bolts!

 

All the newer f-bodies starting somewhere in the early 80's have 12mm wheel studs. 11mm is very close to 7/16" which is what the older wheel studs were. 12mm is just slightly larger.

If you have at least 1/2" of stud protruding past the wheel/wheel stud washer, then you should be fine.

If your wheels use a nut with flat washer, the stud needs to extend past that flat washer. If your wheels use tapered wheel nuts, try installing an open ended stock nut to see how far into the nut the stud goes. If it goes through the nut, then using a capped nut will be fine.

Thanks. My car has a huge fan base

 

Thanks guys, it looks like I'll be alright. Now I just have to replace my 25 year old helmet and I might be able to hit the track this coming Thur.