Vintage Multi-piece Racing Wheel Rebuilding

I would look up the torque specs on that size and grade of bolt and go with that.
When I was on a Super Vee crew in the 80s the BBS rep would come around and torque are wheels with an inch pound torque wrench.

 

The standard torque for a 6mm bolt with 8.8 strength is 9nm. If you are using new nylock nuts, then you don't need to use loctite as well. If reusing old nylocks, which is kind of a no-no, then the blue loctite will work find. The main thing is getting the wheels to seal. On BBS racing wheels, we used to apply a nice bead of RTV silicone sealant all the way around the rim to rim joint on the inside of the wheel once the wheel was assembled. Clean everything once disassembled and check for cracks before reassembly and you should be good to go.

 

Inferior bolts? Counterfeit Chinese maybe ?

 

No, the extra 5 in lbs of torque would not cause the bolts to fail. I would say that the bolts were the cause of the failure. I would recommend using a stronger bolt/nut combination of the correct length from a reputable manufacturer (such as ARP) either 10.9 or 12.9 with matching nuts. Wheel failure is something that should be taken very seriously. You should consult someone that is knowledgeable in this area to determine what caused the failure of the old bolts and what should be done to fix the cause. What was the strength of the original bolts? Were the replacement bolts identical to the originals, as the length of the bolt shank is very important. You don't want the threaded portion of the bolt to be in shear.
As Ronal is still in business, you could contact them for information on the bolt specifications. I would also look at BBS racing wheels to see what grade of bolt that they use and to see if the shank of the bolt goes all the way through the wheel, with the thread just starting at the washer on the inside of the wheel.

 

Doesn't sound like it was ideal if 7 bolts broke during normal use. I would call that a major failure. It could have killed someone.

 

Somehow I don't trust Fastenal. Who makes their fasteners? Where are they made and tested? I am sure that there are some sellers of high-quality fasteners out there that don't cost as much as ARP, but I don't know who they are. You are going to have to do some more research.
You want to do this repair one time and not ever have to worry about it again, don't skimp on cheap hardware.

 

Grade 12.9, bolts are considered 1 time use.

 

Yes, easily. Many times, bolts are torqued right up to but not quit into the yield region. If/when over tightened, they enter the yield region and neither hold torque nor stay together.

 

Who mounted the tires....?
When Luther at the local tire shop treats modular wheels as if they are regular steel transport wheels or they specialize in truck tires and bead them with 150 psi, bad things can happen. I don't know if it is the case here, but it is a source of high stress on the rims.....

 

A dear friend's son is a Manager for Fastenal and I have used them confidently in commercial construction projects.

There is always a possibility of mistake in supply procurement and labeling, (and of course outright fraud!!) but, as you state, "a specification" is just that.
I read the whole thread and some excellent points set forth here.

It sounds like excessive torque may have been your issue, on the first installation.
It takes some sympathy for the metal........"too much" is never the same as "just right'.

Point well made on the shoulder length versus the thread cut zone, too.

Interesting point about Nylocks too.
Good luck and be sure to report back, full circle!

I run some vintage three piece rims.
One of them curb rashed in a Med Center garage, and I just "wear the damage" rather than think about breaking the factory sealing and bolts!!!
There must be 32 or more, around the rim...

 

Be glad to PM his name if you would like his personal attention to your order.

His Branch is on the side of town to serve our petro-chemical refining industry.
Should not be necessary though.

This type of order they will assume your application is critical!!