Minimum safe thread length for wheel studs when adding spacers?
 

What is the minimum safe thread length for wheel studs when adding spacers?

I'm asking because the other day I changed the rear rotors and I wanted to add some H&R 14mm spacers I recently bought. These spacers come with 70mm long stud. 70mm is way too long to be able to fit them without removing the entire hub. maybe, I say maybe but I need confirmation, I could remove the parking brake gears to have lateral access but 70mm may be still too long

Anyway, in the meantime, I measured the 70mm studs inserted in the old rotors with the 14mm spacer. I also fully screwed the lug nut entirely (~27mm), which leaves me 18mm to be filled by the wheel itself + the hub disc

Does anyone know those values by any chance (wheel + hub disc)?

how to calculate a safe stud length with Fuchs wheels?

IF the current wheel bolt/studs are 45mm, adding a 14mm spacer, wouldn't require only a 50-58mm stud? those 10mm can help avoid removing the hub I think



btw my rear wheels are original Fuchs 7Jx16

General engineering rule of thumb is that the nut should thread onto the bolt/stud at least the diameter of the stud or bolt. E.g., if the bolt is 8mm in diameter, then the nut should engage at least 8mm of threads.

Or get an open steel lug nut - if this gets fully threaded on (stud fills nut completely), you're OK...

I can try with an open nut good point.

The closed classic 911 are very long, I measured 26mm of thread, but I counted 6 turns to reach 14mm of thread.

i know is a bit of a strange topic, but I'm really trying to see if I can install some longer studs without pain. otherwise I will return them