Wheel Spacers - minumum threads?

[vesnyder]

Just put some temporary spacers on the rear wheels of my SC to see what wider wheels would look like and was curious what the minimum number of threads should be? I was able to get almost five full turns - normally it is closer to twelve. The spacers I put on are 13mm.

Also it looked like it raised the rear considerably - more than I expected. Is there a rule of thumb here?

[North Coast Cab]

6 would be my guess, but it's only a guess.

Also, I don't understand why it would raise the rear? the tire/wheel OD is the same. It should only have brough the wheel closer to the fender.

John

[David]

The typical rule of thumb I use on fasteners is at least one diameter of thread grip. I don't know what size wheel studs the 911 has, but say it's 14mm x 1.5mm, then it should have a minimum of 9-1/3 turns. This method is a bit conservative, but 5 turns sounds a little risky.

[North Coast Cab]

Vance,
I guess since it is a street only car and you rarely drive it in the rain you'll be fine. Just make sure the plywood spacer is pressure treated so it doesn't rot.

John

[vesnyder]

Graber - Shouldn't you be working?

There's a chance the ride height has not settled, but you think about the geometry it will raise it a little.

As the wood compresses I may be able to get another turn out of it?

Where is a good source for aftermarket tires that fit older 911's? Tirerack has very little!

[ZCAT3]

I was told 9 turns is the minimum you want. Basically you want the lug to thread on at least the same distance as the stud is wide in order to get the maximum strength from the connection. 5 is too little IMO.

[North Coast Cab]

I still don't understand the whole geometry change. Everything should be identical except for the wheel being 13mm farther from the hub. Boune the suspension around a little and take it for a ride. I would think it will return to the previous position.
Also, try 1/4" plywood, it may get you the additional turns you're looking for.

John