Wheel Stud Depth

[Iowa 409 Guy]

I installed longer studs a few years ago. Here is a quote from NHRA rules.

"The thread engagement on all wheel studs to the lug nut, or lug bolts to wheel hubs, must be equivalent to or greater than the diameter of the stud/bolt. Length of the stud/bolt does not determine permissibility. (Example: A 7/16-inch stud must be thoroughly engaged through the threads in the hex portion of the lug a minimum of 7/16-inch.)"

I thought I'd start another thread on this. My lug nuts are 1/2" dia X 1.20 long. When I have my wheel spacer on I end up with the stud .373 in from the outside of the nut. The hex part of the nut measures .629 Measuring the whole nut I have .757 of the stud in the hole which is fine until the "example" which talks about only the hex portion of the nut. I don't want to get off in BFE to a race and have some rule interpreting nazi not let me run because of the stud not being half way through the hex part.

 

[Ishiftem]

I think you are fine.

 

[Don Jacks]

I agree,measure from the open of the stud as installed. You're legal .

 

[La Hot Rods]

 

[Iowa 409 Guy]

I think you are fine.

Thanks Dan, that's the first time I've ever heard that.

Looks like James' and Ron's quotes from the book disagree with each other. WTF According to both I'm illegal according to the rules.

 

[1958 delivery]

Exactly why most run open lug nuts and have the stud sticking out. That way there's no question. How do you measure thread engagement if the nut is closed on the endnot easily

 

[Iowa 409 Guy]

Mine are open.

Should be no problems with the rears. Need to whack them off, probably 50# right there...

 

[La Hot Rods]

If you feel like you have enough thread engagement, run a open lug nut then thread in a stud from the outside.

 

[RussC]

If you feel like you have enough thread engagement, run a open lug nut then thread in a stud from the outside.

It has been done

 

[64ss409]

Thanks Dan, that's the first time I've ever heard that.

Looks like James' and Ron's quotes from the book disagree with each other. WTF According to both I'm illegal according to the rules.

Dave, I don't think they disagree. With 1/2 studs you need 1/2 of threads in the hex part of the nut just as in the diagram that James posted. In other words, you would need at least 1/2 inch of threads sticking out past the washer.

 

[Ishiftem]

Looking at James’s post it makes sense now. If the stud didn’t protrude into the hex portion, then the threaded hollow portion of the lug would be what is holding the wheel on and would be subject to failing. I would get longer studs.

 

[Iowa 409 Guy]

The rules suck. This whole open nut is threaded and has .757 of the stud in it. Whatever stud that is past the face of the wheel ain't doin nothin. The smooth part of the nut is inside the wheel and takes the load. I probably didn't explain that well enough.

 

[64ss409]

What if that lug nut broke just below the hex and there were no stud threads in the hex?

 

[Iowa 409 Guy]

I understand Ron. I was just thinking there is more lateral pressure than outward pressure. Not sure if that is the case.

I'll be going with longer studs.

 

[64ss409]

It's unlikely that anything would ever happen. But I didn't want to get DQed if they checked.

 

[La Hot Rods]

How hard could it be to change them out

 

[Iowa 409 Guy]

How hard could it be to change them out

 

[64ss409]

How hard could it be to change them out

Many times it's harder to find the correct shoulder and length.

 

[RussC]

If you have to change them you might consider 5/8"

 

[Iowa 409 Guy]

Many times it's harder to find the correct shoulder and length.

Been there done that.

But working on things are much easier now with the lift.