I can't seem to find a paint mark (red or otherwise) on any of my wheel studs. From what I've been able to glean the Porsche wheel lock should be installed on the painted stud and the valve should be located opposite the painted stud.

How is it determined which wheel stud gets the paint? Other than the paint itself is there another way to identify which is the appropriate stud?

 

Where is the hole for the valve stem located. Go 180 degrees from that position.

 

That'll determine the location of the locking nut with respect to the valve but there must be some significance as to how the wheel is placed on the hub otherwise Porsche wouldn't have bothered painting one of the studs.

 

I know the 'red' stud was common on 964's, for, I presume, balance, but I have yet to see a 993 with a 'red' stud. I dunno. Maybe Porsche felt this wasnt necessary any longer? More costs saving measures? Not sure..

 

The owner's manual does talk about the topic under the heading "Removing and storing tires" where it states "When fitting tires already mounted on rims, ensure that the coloroed wheel stud is across from the valve."

There's no mention of where the locking wheel nut should be placed.

 

One of the studs on each corner of my car has yellow paint on it, but no other distinguishing marking. Personally, I wouldn't worry about it..... but you could try clocking each wheel and test driving to see if there is a noticeable change in wheel balance. When you find the sweet-spot, apply yellow (or red) paint for future reference.

This all makes me wish I had the on-the-car balancer (Hunter was the brand) from my high school auto shop.... with the car on a jack, it would spin the wheel up to an absurd angular velocity, and adjustments could be made on a wheel mounted adapter to remove any vibration. When the wheel was stopped, the adapter indicated where to place the weights, and the result was amazing.... no vibration anywhere from zero to whatever, since the entire rotational system had been perfectly balanced. Sure beats running back and forth to the tire shop every 5K or so, since they usually only get it right on the second or third try. I should probably look on eBay........

Cheers, Mark.

 

Let's step back and ask a practical question - why care about it at all?
Are you having tite/wheel balance issues? If not, don't worry about it.

Maybe I'm jaded. But I change wheels 4 times a weekend, so...

 

Umm, I may have answered my own post...

From the shop manual, page 4-24 heading "Installing Wheel on Vehicle":

Previous design: the security wheel nut is installed opposite the valve.

From September 1995: The security nut is no longer installed in a special position in production. In after-sales service, the previous practice for tire fitting may be continued. Irrespective of the position of the security wheel nut, it may be useful to mark the bolt opposite the valve before removing the wheel.
This will ensure that optimum balancing results (achieved using finish balancers) will not be affected by tire fitting.

As aways, it pays to RTF(S)M

 

Yup, I do get a vibration at perhaps 60-70 mph so I'm about to get the wheels balanced. Again. And I wanted to be sure I wasn't doing anything that would offset the balancing of the wheel in how it was installed on the car.

 

All 4 wheels balanced with care. Each found to be out by 25-40 grams and all vibrations gone. So much for the previous balance shop done by a so-called tyre specialist who provides support at UK track days!

 

I am not savvy about this clearly. What does the balance of the wheel have to do with the wheel's relative orientation on the bolts? Isn't the tire mounted and then wheel 'balanced' with weights by the shop on a machine and then placed on car?

 

Yes but not the hub, that stays on the car but is a moving mass with the wheel and tyre

 

Interesting thread. For some reason I can't remember I've always situated my lock nut opposite the valve stem, just a habit I've got into.

 

So if I replace the security lug nut with a regular lug nut, do I dynamically balance the wheel or the hub?

how much mass are we talking about?

shirley, you jest.