I've recently bought a 1994 Carrera (993) that has been fitted with 18" 993
Turbo 4 alloys, and have read from a resource site that there is problems
with putting 18 inch wheels on a pre 1995 car - details as follows:

***********

Porsche TSB (Technical Service Bulletin) #9604 says that 1995 993's after
VIN # 99 7 SS 323614 can be modified to handle 18" wheels by attaching a
support bracket on the steering rack housing.
The kit consists of a support bracket and longer allen head bolts. It is
relatively easy to install and is also purported to tighten up the steering
response. The TSB also includes installation instructions.

The part numbers are:
993 347 131 02 Support Bracket
999 218 102 09 Allen Bolt M8x60 (Qty. 2)
999 218 103 09 Allen Bolt M8x80 (Qty. 2)

1996+ 993's already have this modification.

There is some question about 1995 993's before the stated VIN # being able
to accept this kit, possibly related to a mid year steering rack or subframe
redesign.

************

Should I be worried, is anyone else running a '94 car with 18 inch rims??

TIA
Eric
UK

 

Hi Eric,

Boy, this is a discussion we had a while ago, that seems like we never got a real definitive answer.

I too have a 993 w/ VIN# below the Porsche recommended 18" wheel upgrade.

Bottom line seems to be that people put 18" on, regardless of VIN#, with no problems, as of yet. I guess the real test will come with several years of 18" on, seeing if any steering components get weakened or broken. I'm not even sure if the additional bracket that Porsche offers will even fit on early VIN # 993's.

I thought of putting 18" on, but decided to stick with 17" (decision included many factors, but the main one being the unauthorized VIN#, seen through Porsche..)

I've also seen a few folks with 18" on, and no problems. Also, I recall an earlier post that mentioned that this 18" TSB from Porsche might not be needed after all (please check archives..not too sure about this..).

My impression: If your car already has the 18" wheels on, keep them on. If you were debating on purchasing 18", I would say do your homework first, then decide. Just make sure you have the installed 18" steering brackets on your car.

Cheers, and let us know what you did..

 

Thanks Oleg,

The car came with the 18" wheels, so I guess I am going to keep them. I spoke to the guys who used to run RUF over here in the UK (now called GT1), and they said as long as I don't put the car on the track it should be OK. I then contacted Porsche GB, and spoke to one of their technical guys who advised definitely NOT to run with the wheels on there. At the time he couldn't confirm if the rack support could be fitted to my early car (993's came out here in '94, I think you guys got them in '95??).

As soon as Porsche let me know if this kit can be fitted, I'll post up the details.

Thanks again
Eric

 

Here is what I suggest you do.

Look at the bracket. See what its made out of. See where it connects, what it connects to and what its designed to do. Then consider the physical differences between 17" and 18" wheels/tires. Then consider
the other relevant differences between
'95 and '96.

This will give a good basis for a decision.

tim

 

I have a '96 N registered 993 C4, so I assume that from the TSB I have the mod and can upgrade to 18" wheels.

My dealer owes me 4 new tyres, bought the car under warranty and the warranty says tyres must have sufficient depth and/or have correct N rating. They failed on the latter, so we agreed that I'd run the current tyres until they were shot and then get a new set of S02s'

Now, if I can find the money for the rims I could have 18" all round. Ummh

Peter

 

The 27 February 1996 TSB ("Retrofit of 18 Inch Wheels") is superseded by the 21 August 1998 TSB ("Summer Tire/Wheel Summary"). 18 inch wheels can be retrofitted to 1995 Carreras without the addition of a support bracket.

 

I don't see this statement in the TSB in question. Is the TSB you are referring to number 4440? My guess is it assumes the retrofit was already done.

 

Is it possible for someone to post this 21 August 1998 TSB?? Or, where can I find it??

Thanks
Eric

Incidentally, I got a mail from someone who has retrofitted the bracket on a pre vin# car, so seems they do fit regardless of vin#.

Regards
Eric

 

I have a '95 993 with 18" Turbo Wheels. The car came that way. What should I physically look for under the car to see if I have the support bracket?

I have a slight "shimmy" in the steering wheel at around 45-55MPh. I'm going to get the wheels balanced and the car aligned soon. If it does not go away, I wonder if the 18" wheels on my '95 may be the issue?

Sean

 

Guys, what's the problem w'/ the 18'" wheels?

I mean, if you have lower profile tyres and your outside diameter is the same as w/ the 17" wheels, I don't undurstand what could be the problem. What I'm missing here?

 

A shorter and stiffer sidewall tends to put more stress on subframe and other components. The modification is a reinforcement that compensates for the added stress.

 

Eric Kasir Wrote:
Boy, if this is the case, then what's the point of using 18" wheels!!

Since I run my car on the track on a regular basis, I'm not willing to chance any "surprises" on my pre-VIN# 1995 993 with 18" wheels.

BTY, 17" are more than sufficient for me, and I personally love the 17" cup wheel design!

 

1994 993?? IS THAT A EURO MODEL?

 

Yes, the 993 was first introduced in the ROW as a 1994 model.

 

OK, I get it, but that shouldn't be a problem, or should it?