kid23

Good morning everyone,

Please excuse my lack of knowledge - I tried to figure out the offset info

I was wondering if anyone would be kind enough to tell me if the following tire/wheels would fit my 1987 944 turbo without any rubbing on the fenders or lowered suspension(not more than 1 inch):

Offset: Front ET45 Rear ET54

Wheel Size: 18x8.5 Front and 18x10 Rear

Front tires are 235/40/18. Rear tires are 255/35/18


Thank You very much

K

Dave

Not sure but the fronts might be a little tight. Are you familiar with the TSB regarding 17" and 18" wheels?

kid23

No I am not sure what you mean by TSB

Well I wouldnt mind changing the tires in fornt to 225s I was just worried about the 8.5 wheel in the front would that cause problems?

Dave

I couldn't find the whole TSB in a quick search but I know it's been posted in the past so it must be out there somewhere. The jist of it is that Porsche's position on oversized wheels and tire's is that a 944 with 17" wheels needs upgraded caster blocks and adjusters and different wheel alignment specs than a car with 15" or 16" wheels. Porsche also stated that 18" wheels are taboo as the upgrades required to make this safe do not exist.
I found a part of it;
There's a lot more to the TSB than this, but it's all I could find in a quick search. Formerly, I'd been able to find the whole thing by searching for '18" wheel TSB,' but the current search software will not accept a 2 digit number.

pete944

You may need a 1/4" to 1/2" spacer on the front.Roll all the inner fender lips and you shoud be ok. Upgrade to the 968 caster blocks. You can get them from www.paragon-products.com for around $62.00 each.

tifosiman

FYI.

ARTICLE BEGINNING

TECHNICAL SERVICE BULLETIN

17 INCH APPROVED WHEELS & TIRES

Model(s): 1987-On Porsche 944 (with M30 option)
1987-On Porsche 944S (with M30 option)
1987-On Porsche 944 T (with M30 option)
1988 Porsche 944 Turbo S
1989 Porsche 944 Turbo
1989-On Porsche 944 S2

Group: 4
Bulletin No.: 9303
Date: September 28, 1993

SERVICE INFORMATION

Concern

Installing 17" Porsche wheels on vehicles previously equipped with 16" wheels.

SERVICE PROCEDURE

Installation Information 1. Front and rear fender well lips must be reworked and/or checked for adequate tire clearance. See Fig. 1.

2. Suspension travel must also be checked. Parts such as brake lines, hoses and brackets must have adequate clearance.

3. New caster eccentrics, rear mounts and nuts must be installed in the front control arms. This change is necessary due to a change in caster specification on vehicles equipped with Porsche 17" wheels. The specification for vehicles equipped with 17" wheels is 3'-15'-45.
See Fig. 2.

4. Vehicles must have a rear stabilizer bar.

5. When adjusting vehicles to new caster specification, all alignment values should be checked at that time.

6. When summer tires are used on vehicles with 17" Porsche wheels, snow chains cannot be used. If winter tires are used, only snow chains with Porsche Part Number 911 361 924 00 may be used.

7. Tire pressures for front and rear 17" Porsche wheels is to be set at 2.5 bar (36 PSI) at approximately 20'C (68'F).

8. When using this rim and tire combination, a 17mm spacer plate must be installed on the rear wheel hub. The customer must be informed that if the emergency wheel is needed, the spacer must be removed.

9. Not for Cabriolet vehicles.

APPROVED WHEEL & TIRE TABLE

Tire size Rim size Offset Position Note

225/45 ZR 17 7,t Jxl7 AH 65mm Front
Summer tires 255/40 ZR 17 9 Jxl7 AH 55mm Rear
(See installation information A through G.)

225/45 ZR 17 8 Jxl7 AH 52mm Front
Summer tires 255/40 ZR 17 94.@ JX17 AH 68nm Rear
(See installation information A through I.)

205/50 R 17 7;-i Jxl7 AH 65mm Front
Winter tires 225/45 R 17 8 Jxl7 AH 52mm Rear
(See installation information A through G.)

NOTE: When using this rim and tire combination, a 17mm spacer plate must be installed on the rear wheel hub. The customer must be informed that if the emergency wheel is needed, the spacer must be removed.

PARTS INFORMATION TABLE

Description Part Number Quantity

Spacer Ring 951 331 611 02 2
Wheel Bolt 904 341 671 00 10

Wheel Nut 999 1 82 003 36 10


APPROVED WHEEL PART NUMBER TABLE

Size Offset Part Number

7;-i Jxl7 AH 65mm 96536212405
8 Jxl7 AH 52mm 96536212601
9 Jxl7 AH 55mm 96536212800
91.@ Jxl7 AH 68mm 96536212805


APPROVED TIRES AND SIZES (SUMMER VERSIONS) TABLE

Size Makes

225/45 ZR 17 Front Bridgestone Expedia S-01 Nl
255/40 ZR 17 Rear Continental Sport Contact CZ 91
NO Pirelli P700-Z
NO Yokohama A 008P
NO Michelin MXX 3
NO or MXX
NO Pilot SX

APPROVED TIRES AND SIZES (WINTER VERSIONS) TABLE

Size Makes

205/50 R 17 89 H M&S Front Bridgestone WT05
225/45 R 17 90 H M&S Rear Continental TS 750 Pirelli winter 210 Performance

SUSPENSION PART NUMBER TABLE

Suspension Parts

1. Rear Mount

Part Number Quantity Required 951 341 023 00 2 each

2. Eccentric 951 341 431 02 2 each 3. Nut (torque to 100 Nm) 900 910 115 02 4 each

END OF ARTICLE

daniel951

i have 18x9 front and back with 225 fronts and 265 in rear. I did have to use a spacer though but it has been fine. check out pictures at my website or send me a pm if you have some quesitons. ALso i was thinking of putting 235 up front i was going to try them maybe this week.

tifosiman

I assume the spacer was to clear the bearing cap on the fronts? What other improvements have you made to the suspension? Did you upgrade the casters? Sorry for all of the questions, I can't tell much from the site....

kid23

Thanks Guys,

I was always a bit wary of 18 inch wheels anyways.

I think I will just save more $$$ and get some Kinesis ones or wiat till someone wants to sell his used ones ;-)

I guess they are expensive for a reason

K

daniel951

i haven't upgraded to the caster blocks or anything because i saw no need to. Right now the only reason i put spacers on because my offset was a little different compared to my 87 NA. on my 87 na i didn't need spacers but on my 86 951 i needed them for the front because it was hitting the spring. I haven't had any problems driving on them a 1 and 4months

daniel951

1 year my bad

Cass944

someone with some programming experience shoudl just make a small program were you put in the offset of the wheels your thinking of buying then it tells you what you would need to make it work.

tifosiman

Gotcha. You oughtta crawl up under the front of the car and inspect those 944 casters. Large wheels like that will chew up the rubber in them. Consider going to the 968 casters, if only to delete some rubber from the system there and keep the car from tramlining as much on less-than-perfect roads.

Cheers

Jeremy

early85944

Does anyone have any pictures of a control arm failure due to 18" wheels? Has anyone ever seen a failure first hand?

tifosiman

I don't think control arm failure is necessarily the issue with 18" wheels (unless the car is lowered quite a bit, where the arm is less than parallel to the ground). It is the caster blocks that is at issue.