Viken

From looking at these pictures, I gather that your wheels are sticking out too far. Since they are 17's, you obviously have aftermarket wheels with the wrong offsets. That's where your problem is.

Levent

Wheels are OEM, I have the sticker. Can certainly say the same about the spacers. Who can tell the OEM spacer width for 17" rims.

Viken

1- If these wheels are indeed 17" as per your original post, they cannot be OEM because Porsche never offered the Technology or Turbolook in this size.

2- If these wheels are the 18" OEM types, there is no need for a spacer front or rear.

3- The rear spacer that was installed on the C2S only with the factory 9 x 17 ET55 wheels was 31 mm thick. Your car looks like a narrow body C2 which does not need spacers.

[ 07-04-2001: Message edited by: Viken Bedrossian ]

Chris in Detroit

Second what Viken and Terry said:

If your wheels are OEM (do they have a Porsche part number on back ? and I agree with Viken that this style wheel was 18" only) then NO spacers are needed with a narrow body Carrera

I think (and just MHO, certainly acknowledge AJUSA's expertise) the springs resonating seem less likely to be your problem than some other factors. First and foremost because 55mph is absolutely classic wheel/hub out of balance speed ! Every time I've had a wheel out of balance its resonated between 55 and 65 mph - also, because springs will resonate up/down, wheel/hub components out of balance will resonate side to side - seems far more likely to cause a vibration that is felt at the wheel.

Anyway, enough of my amateur opinions. Remove spacers, get rid of rubbing and as for your vibration - if you are sure tires are balanced OK, then make ** sure ** you are torqued to 94lb ft, you must use a torque wrench, since over or under can cause a problem. I had a wheel vibration that drove me CRAZY until I re-torqued to spec - instantly vibration gone.

If the above doesn't work, then you are into considering whether the rotor is out of balance for some reason / not mating perfectly to the hub. All these things seem far more likely than springs resonating.

Let us know if you've eliminated tire balance / wheel torque.

Jack

Levent:

I also agree with Viken on the offset. Looking at the pictures, the rear wheels are sticking out too far--wheel/spacer has too aggressive an offset. Of course, if you like the look, you can try rolling the fender lips. As to why the rubbing started with the new tires, I'd bet the SO-3's have a wider foot print and/or different shoulder design than the Dunlops, even though both tires are the same size.

As a side note, are the spacers hub centric?If not, this could be contributing to your vibration issue.

Levent

OK, I pulled out the sticker and this is what it is says exactly:
On the left hand side under standard equipment:5 spoke "CUP" design wheels., I guess these were 16" wheels because the tires ar 16s
On the right hands under the options:
17" Light Alloy Wheels $1378
Rim Caps with Porsche Crest $214

I am the second owner so I can't ceratinly say if the previous owner have changed the rims, there is no paperwork. I thought these were the original rims. I need to check for the Porsche stamp, now where would that be. Is

This is getting quite complicated and you guys are ahead of me.

1. Vibration issue: My previous Dunlops got balanced three times and torqued to 93 ft lb(I have a torque wrench). The current tires are just put on and I torqued them. This vibration doesn't want to go away. By the way spring resonation is my idea it could be total BS.
2. Spacers: I checked them out (in my previous post I wanted to say that I don't know if they are factory, but I saw that I said the opposite). Fronts have star shaped spacers and they look like 21mm. They are also not lined up with the star shape of the rim. At the back I can't see a spacer. There is this huge disk flush with the brake rotor and it is about 40mm. I need to get this car next to bone stock to compare. I will do that tomorrow, there are five 993s at the place I work.

Here is the action plan:
1. Remove the front spacers. I don't think it is going to be possible to remove the back one, I am not even sure if there is a spacer at the back, the brakes will hit the rim, I think. Vibration is most likely related to front tires since I get it on the steering wheel.
2. Go to the Porsche dealer and see what they say.
3. Go to another shop specializes in Porsche to get their opinion.

BTW, I just measure the rims, the rim diameter, just where the tire starts is 18.5". First indentation diameter is 16.5". If you have similar tires could you please measure yours. Now I have some doubts about the rim size too. On the other one probably couldn't put 17" tires on 18" wheels. I will be soooooo surprised if these are 18" wheels.

You are all great help. Thanks.

Ray Calvo

Levent, from your description your car is similar to mine - '95 993 w/ 17" optional "Cup" rims. Dealer put these on when we negotiated car price. Size matches spec book - 17X7" fronts, 17X9" rears.

I can't check your pretty pictures; they don't upload for some reason.

I NEVER had any spacers on these wheels! In 60K miles and prob. about 5 different rear tires, never had a problem. The aftermarket Mille Miglia wheels (single piece, match to 993 "CUP" style) I use for track tires definitely have about an inch offset to the outside - on these I have had rubbing problems with present RE71 tires. Cured by bending rear inner fender lip up by prying carefully with a 1" diam. pipe (traditional instructions are to use a baseball bat, but it didn't fit).

Junk the spacers front and rear is my opinion.

Re the 55/110 MPH resonance - I have NOT experienced this in 55K miles of driving (have had vibrations, but not this resonance style). Then again, I do NOT have wheel locks on the car. I have heard the locks can cause this - check the archives!!! One potential solution somebody said was to put the wheel lock on the lug facing the tire valve.

Levent

Lesson 1 : One should not post after a 4th of July party.
Lesson 2 : Don't post at 1 o'clock in the morning regardless.


Thanks Ray, at least you agree that these wheels were available from Porsche.

For the rolling part, so you only roll the inner lip only and don't try to pry the entire fender outwards. I can handle that.

Chris in Detroit

Careful, Ray didn't agree on the wheels - he said the pictures didn't load.

The Cup wheels he was referring to have a distinctly different style (more symmetric gaps between spokes) than yours.

You have the swept and twisted spokes of the turbo style wheel - which I don't think were available as OEM in 17" from Porsche, but could well be wrong. FWIW I have your exact style as 18" OEM and as an 17" Aftermarket set of track wheels.

Some other comments - the "huge disk flush with the rotor" about 40mm ** sounds ** like the rotor "hat" - do you have this same thing on the front wheels ? I think 40mm spacers on a narrow body Carrera would have the wheels sticking right out

If you get into rolling the fenders, two tips to try and avoid the dreaded cracking of the paint:

(1) heat the paint (to soften the it)with a hairdryer before rolling - or with 911s go for a nice long-ish hard drive to get the engine hot, which will conveniently heat the rear fenders

(2) tire rack will rent (or loan ?) a fender-rolling device, which is actually quite sophisticated and they have just got the adapter to fit Porsche hubs ! This device mounts to the hub and allows you to make pass after pass on the fender, rolling it slightly each time with rubber type rollers. Definitely the way to go .....

Good Luck

Viken

Once and for all, the 17" wheels pictured on the above white 993 are NOT Porsche factory wheels. These are the 17" *Cup* wheels factory supplied on the 993:

Rocket

Levent...........before you embark on any of the above I would check to see if the wheels are not slightly buckled by watching them on the balancing machine. I have two slightly buckled 18" RS wheels where the wobble is plainly obvious to see on the machine, but they seem to balance up fine but I still get some vibration 85 mph plus.

Check that the garage uses weights on both the inner and outer (or close to outer) edges of the rims which is supposed to be a most accurate method. For example some use big single weights on the inner edge to correct an imbalance on the outer side of the rim....fine if you don't drive over 60 mph.

Does the correct placement of the colour coded wheel bolt opposite the wheel valve make much difference as per the manuals instructions? I've not tried it in any other position to experiment.

Rocket

993 RS

Levent

I will take some close up pictures tonight and you can tell me if there are spacers on the back. As for the front there are spacers and they are quite misaligned. the five spokes of the spacer is not aligned with the rim's spokes. This might very well be the problem.

Chris, I have to check if the fronts have those large disks too. Thanks for the rolling info.

Vicken, do you know where the brand stamp is on these wheels.

Garey Cooper

Levent;

I have a 1995 C2 with H&R Coil-Overs, M030 sway bars, and 17" Fikse Wheels in 8" and 10" widths. I also use 17" Porsche (Speedline OEM) wheels that are 7" and 9" widths. With the correct tires neither of these two wheels rub. I CAN bottom the Fikse's but I've got to drive at high velocity over a bump or depression to do so. I also had Eibach springs with stock shocks on the car when I bought it. These were VERY LOW and the car would scrape over obstructions. Also, in my opinion the handling combination of the stock shocks and sway bars with the Eibachs was not optimal.

Now for my 2 cents,

The H&R's are not too harsh on the street for an enthusiast. Plus you can set the ride-height over a range that may satisfy your local bumpy road conditions. As for quality mine have been superb, I drive them and they work if anything better than when new.

I cannot concieve that the vibration comes from your suspension. This sort of thing usually comes from things that are rotating, wheels, tires, hubs, etc. I suggest you go to a high-line tire shop in your area that has a Hunter balancing machine and pay to have your wheels and tires rebalanced. Even better if they have a machine that will balance them on the car.

As for whether or not the wheels and spacers are right listen to Viken and Ray, these guys know thier stuff.

Lastly good luck, there is quite often a lot of "trial and error" involved in these suspension set-ups.

Jim Sullivan

Hi Levent,
Like Ray Calvo, I had 17" Mille Miglias that looked just like Viken's photo above. They rubbed miserably on my C2S, having an 8mm increased offset, so I sent them back to The Tire Rack. Your photos show a big offset..
Another thing to check - I think all factory wheels have the diameter stamped on the face of the wheel (eg. 7 or 9, etc... I know mine do).

As for rolling fenders, you might want to check with your local Porsche Club as many of them have a rolling device in inventory.

RT7

Levent,

I too have Eibach/OEM shocks with S02 (285/30/18 at the rear) and no rubbing at all at 55 or 140mph. As a matter of fact, I have enough room to put on 285/35 series.

AJUSA is kinda pricey, I took mine to Extreme Motorsports down in Convoy area.

Regards,
Ron