02TransAm/Batmobile

iTrader: (32)

Seems like this is a topic that doesn't get much attention and I need help in clearing up some of the info regarding thread engagement.

General consensus is engagement must equal the thread diameter so M12x1.5 needs 12mm of engagement, M14x1.25 needs 14mm of engagement and so on. So if 1 turn of the nut equals 1.5mm, then for our M12x1.5 studs we need a minimum of 8 turns. Only place I found this rule in writing was on McGard's site:
http://www.mcgard.com/index.php/cust...llationremoval

This rule only applies to steel stud/steel nut applications. For steel stud/aluminum nut applications the rule is 1.5 times the stud diameter. This means you would need 12 turns if using aluminum nuts on F-Bodies. Conversely, TireRack's website shows a minimum of 6.5 turns for M12x1.5 studs which counters the general rule of thumb and makes no mention of type of nut.

So what are the rules? Anyone hear any different ones or have a source for proper thread engagement?

I just swapped out my front studs to ARP 100-7708's because on stock studs with OEWheels DD C5's, I was only getting 5 turns. Might want to check yours if you are running OEWheels.

smitty2919

For any nut/bolt I use it is at least one diameter worth of thread minimum.

25th TA #748

Can someone else with a stock car (or at least stock wheels and studs) check both a front and a rear? I replied to the PM the OP sent me, and the results were different between the front and rear (8.5 and 5.25, respectively.) I'm curious if that is normal, as my car is more or less unmolested.

smitty2919

Running 2.5" ARP studs with dorman open lug OEM nuts that are about 23mm total length are basically flush with a 15mm eibach spacer.

So in other words, with 2.5" studs and 15mm spacer up front I get 23mm of thread engagement.

02TransAm/Batmobile

iTrader: (32)

23mm thread engagement, meaning you have over 15 turns of the wheel nut?

stp001

Batmobile, Just to offer you a little piece of mind. I had a C4 corvette that I installed CCW 17x11 wheels on. With these wheels, I probably only had 5 rotations of the lug nuts. I autocrossed this car with "sticky" tires on a regular basis. Wore out wheel bearing units a couple of times, but never had an issue with a wheel stud stripping loose. I will also admit that I put lug nuts on with an impact. If that wouldn't strip them, what would?

LR WS6

I'm barely getting 5 turns with my OEWheels - seems a bit low. Has anyone else been able to confirm stock wheels having the same thread engagement as 25th TA #748 reported?

farmington

iTrader: (14)

NHRA requires open ended lug nuts so they can be sure that the lug nuts have enough thread engagement.