OK - Ive searched on this topic and I know spacers are a highly debated topic. Im trying to understand the maximum spacer I can run without going extended lugs. The wheels I have do not allow for bolt on adapters and I just need a slight bump out (5-10mm). 10mm would be optimal. I have seen some folks say 7mm max, but not seen the evidence supporting it. Thanks for the info

 

Hpw much thread engagement can you get with 10mm spacers and your studs? I'd say 5-7 mm would be better - I run 5mm GT3 spacers on the rear and have steel lug nuts when I do track days.

 

The evidence is a simple equation. You need at least as much thread on the nut as the diameter of the bolt. Do the math.

 

I concur, 1D at a minimum.

 

7mm Max..........dont risk it

 

If you don't believe us, then switch to steel lugs and try it. You'll find that there's not enough thread left to get the lug nut completely on it.

Like they said above, pretty simple to figure out. First, switch to steel lug nuts. Then simply measure how much thread is sticking out of the lug nut in your stock configuration. That's how thick you can go.

p.s. I would absolutely NOT run 7mm spacer on my wheels (turbo twists). No freakin' way. I have 3mm and my lug bolts are right at the edge of my lug nuts.

p.p.s. anyone who's going to run spacers should switch to steel lugnuts unless you know for sure you'll have adequate engagement for that particular wheel. Or you could use alum nuts and count the number of turns as you install them, to ensure adequate engagement.

 

6mm is max for stock studs on a street car.

 

My wheel guy says at least 5 full turns before torquing it down

 

Wheel studs are M14x1.5 ...... divide diameter by 1.5 pitch = 9.33 turns of engagement req'd.

As most stock stud/nuts/wheels combos take max. 12 turns to final torque, then (12-9.33)1.5= 4mm 'spacer' ..... 6 is OK, no more.

5 turns of engagement is not enough for me ...

 

The minimum torque on a 14 x 15.mm thread pitch is 7.5 turns. 9 is better. Less is not acceptable.

http://www.tirerack.com/wheels/tech/...jsp?techid=107

 

I think it should also be noted that different wheels probably have different thicknesses there, so you should check when adding any spacer.

 

While we're on the subject, when one uses spacers, does that require an alignment? I should know this, but I don't. Thanks.

 

No.

 

I use 8mm spacers and steel lugs sometimes with 996TT wheels on the track and I changed to longer studs. I didn't feel comfortable seeing the stud recessed in the nut.

Greg H.