Bmw635

Ok, finally wrapping up the TB job tomorrow.

I have a set of old RH wheels 18x8 ET52 and 18x10 ET40 that's getting refinish tomorrow. Meanwhile I am looking for ideal tire size for these rims that will fit the 88 S4 chassis. What's the ideal set up ? I am thinking 245/40 and 275/35 but might have fender clearance issue? TIA.

Volla

I had a similar problem on my 88S4

Cycle your central locks from the dash panel button a few times. (ignition on, doors closed, press lock button on dash and wait for motors to do their stuff) After i locked and unlocked 3 times my driver and passenger locks were all good again.

You maybe want to check the central locking relay in your central electrics board, mine failed which is the reason why i have to manually lock with key, but after some time the turning-key locking didnt do the job anymore, it stays open and manual turning the **** on the inside didnt help.

Oh yes, and get the manuals, and the electric schematics, you cannot do anything on the car without them


==================================================
19?? VW Baja Bug (Completely custom, Golf 1.8 motor, and many, many mods) - Currently my daily drive
1988 Porsche 928 S4 Euro/ROW (Black with Ivory interior) - Under ECU surgery
1982 Porsche 924 Euro (Silver with cream interior)- Gone
1982 Porsche 928 S (Manual) Euro (Petrol Blue with Blue with black and white chequered interior) - Gone
1983 Porsche 928 S (Auto, NA spec, Red, black interior) - Gone
1994 BMW 530i Manual (Maroon, grey interior) - Gone

Bmw635

Looks like your sympton in BOLD above might be my problem caused by the synchronization. Only problem now is I was told interior light and door lock were shorted so they pulled the fuse. At least trouble short is easier than trying to open up the door lock so looks like this is next on the list. Thanks.

Rob Edwards

Hard to advise on wheel/tire combos without knowing the offset of the RH's. To run 245's up front requires a lot of negative offset. In back 275's on 10" should be easily doable but it all depends on the offset.

Biggest offset I see listed for 18x8 on GMP's listing of RH wheels is ET 52. (There may be larger offsets in existence, I have no way to tell whether this is a complete listing or not)

https://www.gmpperformance.com/index...ail&PID=233943


That isn't going to work with 245's up front unless your ride height is like a desert truck's.

Bilal928S4

Usually the interior lights are the culprit. Take each one out to make sure the power wire is not touching the frame etc. I Usually put shrink tubing over all the connectors so that they don't accidentally touch any thing else while installing the lights.
HTH

Bmw635

I updated the wheel offset above. 18 x 8 ET52 and 18x 10 ET40. Had to measure.

Is the problem with the high profile or width? I read 235 is ideal for 8" W and 295 is ideal for 10"W but I think the 295 will not fit the rear. I have 275/35/20 rear on my 740 and it's wiiide.

Rob Edwards

The problem is width- I have 18x8 ET54 on the front, with 235 Sumitomo HTRZIII tires and near-stock ride height (~165mm) I wouldn't want to be any closer to the fender than I am, and at ET52 you'd be 2mm further 'out'.

Ignore the ridiculous ride height, car was just jacked up. This is my '90 GT, which has rolled front fender lips. Don't think an early '89 S4 has rolled lips, just the '89 GT (and all '90-95).





In the rear on an S4/GT this is what 18x10 ET 58's with 295's looks like. At ET40 you're 3/4" further out, so you'd be further away from the lower control arm in the rear, but closer to the fender lip. 275's will be no problem.



Here's the 295 on 18x10 ET 58, close (~5mm IIRC) to the rear lower control arm.



It's the front that's usually the problem with 928 fitment- gotta get as much negative offset in front as possible.

Bmw635

Sweet, thanks Rob. What's the profile on your 235 and 295? I guess 40% and 35%?

I can have the hub mating surface shave a little if there's a lot of material. I plan 275/35/18 in rear but it will look like V from the rim so may be 285/38/18. Thanks.

Peter

James Bailey

."..I can have the hub mating surface shave a little if there's a lot of material. I plan 275/35/18 in rear but it will look like V from the rim so may be 285/38/18. .."
Most of the Porsche style wheels due to the acorn style nut have little extra material before it starts to really compromise the strength.

Rob Edwards

235/40ZR-18 front, 295 /30ZR-18 rear.

Keep as close to 25" diameter front and rear because ABS.

MjRocket

Rob

I have 295/30ZR-18 on the rear but was thinking of going 215/35ZR-18 on the front for a bit of a streched look...Any thoughts on this good or bad?

My front wheels are 8" wide.

Thx

Rob Edwards

I wouldn't do a 215 with 295's in back, unless you want to be the king of understeer.

MjRocket

Lol...I hadn't thought of that.

James Bailey

You think having 16.2 inches of tread on the front and 21.2 inches in the rear might get interesting ?? Plus the max load rating on a 215 is around 1,100 lbs which under braking and cornering loads could get exceeded.

MjRocket

Yeah I see its not a wise idea, glad I asked..Thanks for the information gentleman.