Wheel / Lug nut dimensions

[ALEX P]

Does anyone have the lug nut / wheel nut dimensions for 911's? To be more specific, it is actually the wheel dimensions that I am after.

I have a set of 4 wheels, 3 of them have the correct radius that the nuts torque up onto however one of my wheels has a flat surface so not ideal.

What I would like to do is machine the rim to add the correct radius but cannot find the dimensions I need and measuring my nuts is a pain

I actually thought that this would be a really simple thing to research but I'm not doing so well

Thanks.

[Bill Verburg]

Originally Posted by ALEX P

Does anyone have the lug nut / wheel nut dimensions for 911's? To be more specific, it is actually the wheel dimensions that I am after.

I have a set of 4 wheels, 3 of them have the correct radius that the nuts torque up onto however one of my wheels has a flat surface so not ideal.

What I would like to do is machine the rim to add the correct radius but cannot find the dimensions I need and measuring my nuts is a pain

I actually thought that this would be a really simple thing to research but I'm not doing so well

Thanks.

911 has R14 ball seat.

14mm radius

[ALEX P]

Originally Posted by Bill Verburg

911 has R14 ball seat.

14mm radius

Perfect. Thanks Bill

[David]

Any idea where to find a 28mm diameter ball end mill? Any other suggestions besides CNC'ing each hole?

[MBAtarga]

How much is it worth to you? $341.75 ?

https://www.zoro.com/dormer-hss-e-bright-ball-nose-end-mill-28mm-c505280/i/G8978210/

[David]

I can likely get one ground cheaper locally. So here’s the rest of the story: I had some wheels made for my 930 years ago. The Porsche lug nuts didn’t seem to fit the spherical machined wheel bolt holes but I figured it was probably OK. After fighting a vibration issue for awhile, I’ve come to the conclusion the wheels were machined for R13 lug nuts rather than R14. I’ve ordered some Audi/VW R13 lug nuts which will hopefully fix it.

[David]

I received the supposed R13 lug nuts and gave them a try. No luck. Still have steering wheel shake. I even put a borrowed set of Fuchs on with the R14 lugs and shake does go away. So I did some measuring of the R14 Porsche lug nut, the supposed R13 lug nut, and a mold I took of my wheel.

Turns out the R13 lug nut I bought was actually 12mm and my wheel is in fact 13mm. So I'll try again to procure some R13 lug nuts.

[911pcars]

Unless the wheel nuts are actually loose rather than not form-fitting, the steering shake might be due to something else.

Sherwood

[safe]

More likely a rim or tire issue would be my guess.

[dg567]

I would check your wheels and tires. Make sure the back hub of the wheel is perfect.

[David]

I checked the wheels with the tires off and they run-out about 0.010" so pretty darn straight for wheels. I've run the 16" Fuchs twice between runs on my 17" wheels and they are definitely better. I'm waiting for some R13 lug nuts before making another test drive with the 17" wheels. Why is it so hard to find R13 lug nuts!

[David]

Anyone have a suggestion for where to find R13 lugnuts?

I’ve ordered 3 different sets and they’re all R12

Edit: I talked to a 4th vendor who says his really are R13 even though he hasn’t checked with a radius gage. Hopefully 4th time is the charm since I have way more than the price of lug nuts in shipping all these.

[Mark Salvetti]

How about talking to World Motorsports? I don't know if they have a presence on B&S here, but they are a Rennlist sponsor. Make all kinds of lug nuts and studs.

Mark

[safe]

I have a very hard time believing that the wheels would "uncenter" themselves if you snug them up carefully before torquing them down. Check it with an indicator on the car.

Have you rechecked the balancing of tires? A failing tire can give shakes.
Checked ball joints, tie rods and wheel bearing for play?

[David]

There is no centering hub. Only the lug nuts provide centering.

In this picture the outer ring is the R14 lug nut wear area, the inner ring is the R12 wear ring and the middle ring is anti seize I put on the R12 nut (there was no metal to metal contact at the anti-seize ring).

[safe]

Only lug centering should be fine. If the contact patch is circular but not contacting the entire seat it should also be fine, but not optimal.
How about the possibility that the seat is not milled perfectly on the studs, if so the correct nuts will still not help you.

Have the seats recut to the Porsche R14 and try to get the hub to help center.

Measure if the wheel really are off center torqued down on the car.