We installed 30mm spacers for the rear wheels. The studs are long but not as long as the GTS studs. Installed the new Cup 2 wheels with 285 tires. The bolts now have only 9 complete turns. I guess with longer studs you have 15 complete turns on the bolts. Is having 9 turns for each stud safe ?
Thanks for your help.

 

Thread pitch is 1.5mm. 9 x 1.5mm = 13.5mm. Thread diameter is 14mm. I think rule of thumb is the lenght nut goes on threads should be at least same as as diameter. So it's right there at lower limit. If you want to feel little more secure install steel lugnuts instead of factorys extra light stuff.

 

Thanks, never considered steel studs . Are they safe or do they have any downside other than the weight/ rotational inertia

 

Steel lugnuts that is,

 

The trick, from what I recall, is making sure to get the right seat on the lugnut. ie they are a less common hybrid, not fully rounded nor cone-shaped. They are definitely available though.

Or, given that I don't think cost is much of an impediment, H&R makes some great bolt-on spacers that fully resolve the issue.

 

Thanks,
I prefer not to use bolt on spacers but if my current setup does not work I will either decrease the with of the spacers to 25 mm or go with bolt on spacers as the last option. If 9 turns is OK , my problem is solved.

 

With steel lug nuts, the rule of thumb for those of us driving on race tracks has always been 9 full turns of the nut when torqued to spec is OK. So - you may be OK for street highway driving. But, I'd check the torque frequently for a while if it were my car and my safety.