I'm driving a ''97 C4S, with the same wide body, suspension, etc. as a 993 Turbo. It's lowered to ROW height. They don't make any all-season tires for the C4S, The standard Turbo tire is 225/40 ZR18 at the front and 285/30 ZR18 at the rear. Factory spec for my car is 275/35-18. Questions are swirling at my mechanic's shop about the off-size ( 10mm wider) causing problems with the differentials, etc. I see guys driving 993 Turbos have all manner of size variations. Also my C4S isn't tracked or even driven hard. Tirerack says they can't put a company guarantee on a non-spec tire ...but they see no problem.
Info and experience would be appreciated.

 

Don't know where the 275/35 came from but the stock setup for all 993 C2S and C4S is
8ET52 &10ET40 w/ 225/40 & 285/30 tires

some did use rear 10ET65 w/ 20mm spacers

when off sizes are used the concern is tire OD which wants to be equal front and rear, but can have < 5% variance tp keep ABS, ABD and diffs happy

 

Tire sizes that I’ve used over the years. On
BBS E88 18''x8.5'' ET57 wheels w/ Gold Centers
BBS E88 18''x11'' ET42 Wheels w/ Gold Centers
F235/40 R315/30
F245/35 R295/30 - my preferred size at the moment given availability and variety.
F245/40 R295/35

 

You're right Bill, my bad. The issue has been resolved. Guys in the shop couldn't reach the owner ...too bad, everyone these days is so terribly afraid of being sued or losing their job for stuff like mounting tires. It's pathetic.

 

I would stick with stock sizes 225/285

 

I’ve tried a bunch for 18” offsets I use:

8.5x18 et52, 11x18 et 40
car is lowered, -3 or so camber

235/40 and 315/30

255/35/18 and 315/30/18

I liked the latter in Toyo r888 the best.

 

I'd recommend the Michelin Pilot Sport 4S in 225/40 & 285/30. Just don't drive the 993 when it's below 40F or snowing.

 

I always run 315's in back and have squeezed 265's up front. but run 245's usually

 

Is this ona 993 turbo? Do you have any pics as just about to place an order!
Thanks

 

Found you! Thanks
https://rennlist.com/forums/993-turb...he-day-10.html

 

I Ran These No Worries On Modded 993tt, Only Summer Tires Ava looks like

• 245/35ZR18
• Service Description: 92Y Service Description
• Load Range: XL Load Range
• Eco Focus: N/A
• UTQG: 340 AA A UTQG
• Max. Load: 1,389 lbs
• Max. Inflation Pressure: 51 psi
• Tread Depth: 10/32"
• Tire Weight: 22 lbs
• Rim Width Range: 8-9.5"
• Meas. Rim Width: 8.5"
• Sect. Width: 9.8"
• Tread Width: 8.4"
• Overall Diam.: 24.8"
• Revs. Per Mile: 839
• Country of Origin*: SKSK

• Size: 295/30ZR18
• Service Description: 98Y Service Description
• Load Range: XL Load Range
• Eco Focus: N/A
• UTQG: 340 AA A UTQG
• Max. Load: 1,653 lbs
• Max. Inflation Pressure: 51 psi
• Tread Depth: 10/32"
• Tire Weight: 26 lbs
• Rim Width Range: 10-11"
• Meas. Rim Width: 10.5"
• Sect. Width: 11.9"
• Tread Width: 10.3"
• Overall Diam.: 25"
• Revs. Per Mile: 832
• Country of Origin*: CZCZ

 

I’ve run 18” 275 r888’s up front and 335’s out back and they fit. Deleted the fwd though.