Jadz928

I installed a set of Turbo replicas on Perl. The rears (10" wide) are slightly too inset. Rubbing rear muffler.

To remove the lug nuts, I counted 12 turns.

I'm trying to figure out the largest spacer I can use without going to longer studs, or a studded spacer.

Any help would be much appreciated. Thanks!

ErnestSw

The nut must engage the stud completely, ie full depth.

hacker-pschorr

Kind of a half-assed rule of thumb. Get a steel lug nut with an open end. If the threads go all the way through you have enough threads.

IIRC that is what they look for at tech inspection for track events.
On the 79 the threads are flush with the end of a steel lug nut, this passed tech.

dr bob

A general rule-of-thumb on threaded fasteners is that you want 2-3 threads exposed past the end of the nut. For the closed-end lug nuts, this gets tougher. Most folks say that 7-8 is absolute minimum. I'd be more cautious for track time. That comes out to a 6mm or so spacer as max (5 'extra' threads time the 1.25 pitch). That's about 1/4" thick, which may or may not buy you the clearance you need. If you are planning these as a longer-term install, get the longer studs pressed in to your hubs and be done with it. The studs aren't outrageously expensive, and getting them pressed in isn't expensive either. The work is getting the caliper/rotor off and the hub out. Plan on replacing the rear wheel bearings at the same time if they haven't been renewed in a while.

Or get the bolt-ons with their own studs.

joejoe

I believe you want 7 complete revolutions. That is how many for the open end lugs I used when I put s4 rims on the 86.5 (it has the longer studs) I had to remove the spacers as they pushed the tire just on to the fender. Tried using the spacers on the '81 to push the phone dials out a bit more, but it has the shorter studs and I could only tighten the aluminum nuts 4 turns. This was obviously not real safe so off they came. I then bought some aftermarket spacers, installed, and all was good with the mounting part. However when driven there was a slight bouncing that almost seemed like a lost wheel weight.. Turns out all weights were good but the spacer was not hub centric so could not get it centered correctly. Again off they came and now it is just stock set up. Make sure the spacers are hub centric (they fit tight over shaft) and over studs close.

Mrmerlin

get the bolt on bolt on spacers, they come in various sizes. With the car level on the ground measure from the outside sidewall of tire to inner lip of fender how much clearance do you have?? Remember that the rear wheels go in at the top when they compress how wide are your rear tires whats the offset of the rear wheels and size?

Jadz928

Thanks everyone! I agree it would be safe at 2 thds beyond an open lug.

Funny thing is I'm not sure if the wheel will rub the muffler with the car on the ground. I noticed it last night while draining gearbox. Let me check it after I'm back on the ground.

This wheel is the 18" x 10" ET65. The wheel clears everthing else on the inside.

The only other reason for a spacer would be to fill out the wheel well. If I chose to do this, I may just go with a studded spacer.

blitz928

I have the exact same wheels on the rear and I used a H&R 21mm bolt on spacer. I still have 1/2" clearance from the fender.

mark kibort

For racing, there are rules that the nut should go the distance of it threaded diameter. usually about 6 turns min. Scot has been racing with 6 turns. I did it for a long while until i changed out the studs in front, and then got the right offset wheels. so, to answer you question, this means you might be able to use a 1/4" spacer , but certainly a 1/8" spacer. you are probably rubbing on the front part of the lower control arm too.

mark kibort

does anyone know for sure, if you can chance the studs without taking the bearing out. No chance of them being pressed out on the car?
Its been long time since i did a rear bearing job, I dont remember what it looks like apart.

mk

Vilhuer

No hope whar so ever.

mark kibort

pulling the bearing or doing it on the car?

mk

Vilhuer

Doing it on the car. Pulling shaft out of the bearing without bearing inner race coming along is possible in theory but its very unlikely in real life. I have seen it done once when there was fresh copper paste between bearing and shaft. Anything which has been together for years is stuck.

Jim bailey - 928 International

The rule of thumb is 1 1/2 times the diameter of the stud. Some allow 1 times the diameter BUT that is with similar metals .....add in softer aluminum and more is clearly better. Also the threads on the nuts do nut go all the way to the bottom of all the nuts.

Lizard928

If both parts are steel then 1x the diameter of the stud/bolt. If steel stud and aluminum/magnesium nut, then 1.5x the diameter of stud.