Steve Weiner-Rennsport Systems

Exactly!!!!

The rear wheels are either too wide, have the wrong offset, or maybe there are spacers that need to be removed. This is not an uncommon problem.

Ride height changes, rolled fender lips, and even camber adjustments will not resolve the rubbing problem.

cumd20

Guys – first let me apologize for not getting more data on the first post before I sent it. As most of you know I am a newbie and had my first drive yesterday of the new toy – so was data hungry. I should have waited until today to write this up properly. Just so everyone knows still love the car and am not phased by this – buy a used car buy someone else’s heartache – I will get this sorted and still be very happy.

I have to fly out on business in 2 hours to Europe so am out of the loop (or at least away from the car) for a week but here is some background to save you reading previous posts then some more info not in the posts.

CAR FACTS AND HISTORY
• I bought it a month ago sight unseen and from a private party.
• It is a 1994 964 factory Strosek mega wide body speedster – converted at Strosek in Germany at new (earlier reference to rolling arches)
• Bilstein PSS9‘s were fitted as part of the conversion process by original owner
• The PO fitted new Rear tires 150 miles ago at a Porsche dealership
• Since that change the car now has Goodyear EAGLE 235/45 ZR17 on front and KOMO ECSTA 285/40 ZR 17 on rear
• The PO-1 had the car lowered on the Bilsteins – hence the pictures which were loaded years ago on Rennlist – they were PO-2
• It has 23k miles on it – and hence so have the Bilsteins
• In the last few years no changes have been made to the spacers used to fit the tires to the strosek body

As I see it right now – I only really have a problem on the Passenger side - there is a difference in ride height in that the passenger’s side is at least 3/8 inch lower. I have used a door wedge to show the difference in the pictures here. In effect I can only insert my fingers at 12.00 o’clock on the passenger side to the edge of my nail, on the driver’s side they will insert up to my first knuckle.

Though the two different ride heights at the rear are an issue I think the fact that the tires are new may also be playing a part in this just being visibly now that the tire wall is possible a different shape than the last set. I learnt this morning that I do not have the special tool to take the centercaps off so I was unable to get the wheel off to show pictures of the suspension.

I think that the Passenger side either has a suspension problem or the adjustment was done badly or that it has lowered over time some how on that side and the fact that the new tires have just been fitted at the rear is what has brought it to the fore now.

sml

i'm only guessing from looking at the photos, but I think you can get this sorted by dialling in some more negative camber

looking the rubbing, it seems you only need about 3-4mm of extra clearance and if you can dial-in an extra 0.5 to 1 degree of negative camber, i think you will be fine.

... as long as you are happy with the trade-off ....
benefits - hopefully no rubbing, improve cornering performance, looks
negatives - tyre wear

sml

i know you are a very knowledgeable guy, but this is incorrect.

when i watched the alignment guy change the camber from about 0 to -2, it moved the top of the tyre inwards by about 8mm. it was quite significant. do you know the camber setting on this car?

obviously a fender lip roll increases clearance by about 3mm or so, and you can squeeze another 3mm or so with a slight fender flare. or does this car have fibreglass guards that cannot be rolled?

you wouldn't want to go down this path, but obviously a high ride height could solve the problem.

this 10ET40 was an easy fit .....

before ...



to this .. but i messed it up and created far too much clearance ...

sml

with -2 camber, my tyres lasted about 4000 road miles.

they were assymetric tyres of 180 treadwear (quite soft tyres), so i couldnt switch them over to the other side. with directional tyres, you could flip them to the other side, and then you should get 8000 miles.

not the ultimate in tyre wear, but performance is improved and it looks great too

Steve Weiner-Rennsport Systems

Two degrees of neg camber is perfect for cars used for track days, however that severely compromises tire wear and that's why I wrote what I did.

The vast majority of my clients need 10K+ miles or more out of their tires and simply adding neg camber to fix a rubbing problem is a band-aid, not a real world solution.

Dave's ride height looks close to me and thats why I didn't recommend any changes at this time. Without question, one can raise the car, however thats also a band-aid when the owner wishes to retain a ride height commensurate with good handling.

JMHO, naturally.

sml

a set of tyres is only about $800-$1000 .. so if they last 8k as opposed to 10k miles, i dont see it being a huge issue .. particularly if you can afford a 20yr old porsche 911 .. even more so for a special $70k 20yr old porsche 911.

for a $50 alignment to dial in some neg camber, plus with the benefits of improved performance, i tend to think the cost-benefit analysis outcome would be in favour of a quick camber alignment.

cumd20

Thanks for al of the dialogue - the value is in the debate as hey say - however - doesn't the fact hat the left and right rear are very direct heights influence the choice greatly.?

It feels like something is amiss on the passenger side.

sml

if it was my car, i would:

a) get the rear wheel alignment tweaked (as I'm guessing but I think you have some the ability to dial in some more neg camber), then

b) at your next service in 6 mths or so, get the ride heights lowered further and adjusted accurately ... btw when you say the ride heights are not equal, are you measuring from the official 964 measuring points under that rear suspension arm thing?

cumd20

No i am afraid no - nothing that sophisticated as official measuring points - you are dealing with kindergarten P ownership here.

Btw - I am in the air on a delta flight using bogo - is this the first reenlist enntry from 35000 feet

As you can see from the pictures before I have used three crude methods to determine they are not equal:-
1 - they bloody well look very unequal - even to my weary and tired eyes. Even after moving the car around to load it differently before parking.
2 - only one tire is having this issue and it is on the passenger side - and as I said - I am over six foot and 240 lbs in the driver seat
3 - the magic wedge


Anyway - still viewpoints appreciated from all.

cumd20

OK - been out of town again (this time to Augusta for the Masters so not compaining ) and just delivered the car to the Pacific NW recommended Rennlist guy (or one of them) yesterday

I hate reading threads that tease you along then simply do not complete leaving a hungry solution seeker hanging - so I will close this thread out for now with the following update.

I wanted the car to be right so asked for the expert opinion of Chris Powell of Chris' German Cars in the Seattle area (impressed me so far).

As I was explaining the issue to him I felt stupid when I literally almost diagnosed the whole thing in front of him and he then of course verified.

The PO had new tires fitted 150 miles ago and two things have combined to throw me on this issue:-
[/LIST]the tire wall profile is very different on the new tires compared to the last set on the back as the new set are a MUCH squarer profile causing material contact where the last set of goodyears fitted very snugly inside of the arch.
[/LIST]either deliberately or by accident - it does not matter which at this point - the Bilsteins were never set up exactly the same on the passenger and driver side by about 1/4 inch. This explains why the wear is evident on one side after the new tires were fitted and i took the misses out for a ride (I will point out she is a mere 130 lbs)

It looks like the car set up was for performance - this may have even been with a 250lb driver and no passenger in mind. Given its intended use I will have the whole suspension set up as street and level. This will raise the PSS9's a little and I will have a corner balance and alignment done while I am at it.

I will let this tire set run down but the next set will be profiles similar to the GoodYear set - which will allow a more cosmetically pleasing lowering of the PSS9's at that stage.

The good news - while it is in there I have told them to do a complete valve adjustment, I have no idea when one was last completed - and this is a chance to get a real good look over the car.

Once I get it back and have it detailed - the new Strosek Speedster will be getting some pictures taken and loaded onto here

Thanks for all of your help on this guys - and sorry for being such a noob and not being more systematic in evaluating potential causes - now I look back on this I feel like an idiot and a couple of you had been trying to point in the right direction.

sml

why not do the alignment check first?

you might find you can dial in a minimal amount of neg camber and then lower the suspension.

rsr997

1st off amazing car! I would honestly get the desired ride height dialed in. Followed by getting corner balanced with the driver in car. After that get a proper alignment and if and only if you still have fitment issues. See if slight negative camber will help you. If not, replace the rear tires with a 275/40/17 or a 285/35/17 in the rear only.

sml

This is a good idea .... to help clarify, he is suggesting NOT to rush and raise the ride height. Your desired ride height may even be lower than the current height.

rsr997

Thanks, nailed it for me.