jneteler

While washing the car this weekend I noticed some unusual tire wear. It is on both front tires on the outside edge of the tread. The edges seem to be abraded.

The car is a RHD ’91 C4 running Michelin 205/50 ZR17’s.

The PO installed a Gemballa suspension to what seems to be a very low ride height. I can only get one finger (~1cm or ½”) between the top of the tire and the bottom of the wheel arch.

I have driven only on the street with some spirited drives through the local highlands.

Any insight as to the tire or ride height would be greatly appreciated.

Regards,

JNeteler

ilko

What offsets are your front wheels? They seem to stick too far out. I think that's the culprit, not the suspension. Your tire size is also correct.

MisterRisky

Have your fender lips been rolled? I agree with ilko that it looks like rubbing on the lip of the fender. If you pull the wheel and tire off I bet you will see rubbing on the lip.

elbeee964

(Maybe you've even heard this tire-fender lip contact above the normal ambient noise, but dismissed it at the time as 'something else'?)

Danz C4

This is caused by the bumper cover metal bracket edge that is at the joint of the bumper cover and the fender joint area. See Adrian's book, page 286. You will need to use a grinder or Dremel tool to cut back the edge of the bracket to be flush with the rest of the inner cover. It's the seam towards the outside front of the car. Not difficult. I did mine AFTER it cut the tires. If you don't like the look, just switch the tires on the wheels, putting that abraded side to the inside. At least in my case it is superficial damage only about 2 mm in depth.

You'll want to install the steering stops too.

The ride height is probably too low in any case. For a street car you should have no less than 1" gap above the tires unless you have the RS suspension components. I'm running the H&R's with green springs with that gap and everything clears just fine. I have Michelin 205/50 ZR17’s on Cup 2 wheels.

Regards, Danz C4

jneteler

Thanks for the input guys...

Ilko, Not a clue as to the wheel dimensions. These are the Fittipaldi model from OZ Racing. Checked their web site and they don't even list the wheel any more. A pointer in the right direction is always appreciated.

Mr. Risky, I don't believe the fenders have been rolled. See picture below.

EllBee, You're scaring me. Are you that apparition in the passenger seat? There is a tiring scrubbing sound when making full lock turns in the parking lot. I thought it was the tire scrubbing against the concrete.

Danz, Thanks for the page reference in Adrain 's book. Does anyone know if 964 347 325 02 is the current part number or has it been superceded. The car has always felt like the suspension was not quite correct because the front end would launch off of bumps that wouldn't phase my C class.

On page 262 of Adrian's book there are tables for the various model specifications. I gather from searching the numerous threads here a ride height half way in between the ROW and RS should be acceptable for a NB C4in street use. Any dissenting opinions?

Is the wheel supposed to be this far forward in the wheel arch? See second picture.

Thanks again,

JNeteler

velocitylover

+1 on the steering stops (see the tire rubbing marks inside of the fender-hence full steering lock noise )

elbeee964

Me, an "apparition"?
I haven't gone X-Files' 'trans-dimensional', if that's whatcha mean... that I'm aware of.

But I've been in your shoes with my newly-bought-car's rear tires.
They had 28mm spacers (that I wasn't aware of) and during spirited compressions/accelerations they'd rub rear fender inner lip. Even left smeared rubber on metal, I found out later.
But sounded like "exhaust scraping asphalt" -- so that's what I rationalized at the time... [idiot!]

Our cars tell us SO much at times, if only we listen with open minds.

MisterRisky

96434732502 is still available and has not been superseded. I used the search engine over at Tischer Auto (getporscheparts.com) and did a search on the part number. They show it for $27. You should price against sunset and pelican just for good measure.

MisterRisky

When my fan bearing was dying I had advance warning via a rattle that I thought was a lost exhaust shield and a slight smell of something getting hot which I tried to find but was unable to locate. Once the metal shavings were coming out the dash vents I was able to much more quickly appreciate what she was telling me.

elbeee964

lol
(-just like your own traveling snow globe!)
Our exhaust systems -- the red-headed step-children of our quickest indictments.


"Denial ain't just a river in Egypt."
-Stuart Smalley

jneteler

No real work has been completed yet but here are a few more bits of information:

The front wheels are 8 1/2 J x 17 H2 E56 and the rears are 9 J x 17 H2 E50. I presume the last two digits are the offset.

The point of tire wear has been identified as the leading edge of the at roughly a 2 o'clock position when looking at the right way. The left side is rubbing in the equivalent position. The shop suspects the castor is improperly adjusted.

The right height was "OK" but not recorded despite asking on several occasions.

Scuff marks were noted on the inside of the fenders so the steering stop mod still needs to be done.

Now for the weird part. The car was on the lift supported allowing the wheels to be suspended freely (i.e. not sitting on the ground). There was a noticeable difference (about 1 cm) in the distance between the top of the tire and the fender. Further inspection reveals there is a difference in the springs.

The technician revealed that the Gemballa suspension was actually manufactured by KW and the spring rate for the front was around 220 or 230.

The photos were taken with a camera phone so pardon the (lack of) quality.

Any suggestions, comments or...

Regards,

JNeteler

Rocket Rob

+1 on the tire rubbing the fender lip. My C4 does it too. My car is only driven on the street but it doesn't seem to do any harm besides scuffing the tire. Are you experiencing any other problems or just the blemishes on the tire itself?

jneteler

Just thought I would post the end of the story here in case anyone finds the info useful.

The shop dismounted the front shocks and then advised that I needed new shocks. They quoted RM28500 for a set of replacement Gemballas or RM8000 for a set of HWK's. No I didn't shift the decimal point. (3.25Rm = 1 USD)

Gee, how could I possibly refuse...

I told them to put it back together with the original parts and raise the ride height 10mm. I thought it felt better on the ride home but I was off traveling for a week in Europe. Also noticed that the aircon had packed it in again.

Last night I finally had a chance to go for an extended drive and can confirm that increasing the ride height made all the difference in the world. It doesn't bottom out anymore and seems to handle better.

I guess I'll wait on the shocks until they are really needed. And import a set personally from a reasonably priced outfit. By the way, the Gemballas mounted on this car are actually made by KW.

Oh, if anyone is interested the aircon was replaced with locally sourced parts (compressor, reciever dryer, etc.) and is working wonderfully again. If anyone wants more details I can post a separate thread.

Regards,

JNeteler