Jiefei

Hi, I want to customize a set of 18-inch wheels for my 911 Targa (wearing summer tires, but mostly for cosmetics). So definitely want the wheel to stick out a little more (just close but not beyond the fender). something like this


But I'm also worried about the rubbing issue. I don't want any rubbing issue and don't want to roll the front fender lips if possible.

Front: 7 x 18, ET 23, 215/40
Rear: 9 x 18 ET 15, 255/35

The car is a 1988 (Super Carrera) Targa, currently running on 16 x 6/7 Fuchs (I'll definitely keep those for all-season tires).

I got the pics below but not 100% understanding it...

Jiefei

Here's the comparison with the current 16 Fuchs setup

front

rear

wildcat077

Unless you dial in lots of negative camber and roll your front fenders , 18 inch wheels are not a very good option …
I run 17 inch Fikses on my 89 with Continental 275/40/17 rears and 245/40/17 fronts but i rolled my fenders and have lots of camber.
Bill Verburg has an extensive wheel size and tire chart , maybe he’ll chime in and offer some advice, he’s the resident wheel and brake guru !

Cheers
Phil

theiceman

i had 17s on my stock setup . I will see if i can find a pic .. i saw someone with 18s once and i didnt like it .. just didn't look period correct at all ... and looked kind of ricerish ....

I eventually went back to 16s and i am glad i did....





the rear i had did not rub at all , the fronts i had barely touched with hardly any camber. and even if i really plummeted the front end.

if you want the sizes and offsets let me know. i dont run these wheels anymore and they are in the shed, but i think i have the original paperwork somewhere

sorry about the crap pics

wildcat077

My 89 a few years back with 17inch Fikses … yes the brakes are huge , it’s a 996TT conversion and yes the car stops on a dime !

Cheers
Phil

wildcat077

Those are 8 and 9 inch wheels , not sure if it still had the Dunlop tires at the time , it now has Continental DW’s

Cheers
Phil

Jiefei

Thanks! I'm looking for a similar feeling to this 993 turbo with a 19-inch HRE 522M. So I think visually 18 inches should be fine.



Seems that rolling the front lip is a must. @Bill Verburg I got the chart above from you actually, but don't fully understand. Could you suggest which ET/width should I go with the 18-inch wheel on the 911 SC (Targa) with no/minimal rolling front fender lip? Thanks and happy thanksgiving!

Bill Verburg

The colored boxes represent the max envelope dimensions for what fits, the closer to any given edge an actual wheel/tire set is the more issues that will need to be addressed for a fit.
there are 3 dimensions to the fit envelope
tire front space , tire back space and tire OD

the wheel ET determines the tire ET so we usually start w/ that

max front space available for an SC/Carrera front tire is ~89mm or 3.5",
max backspace is ~146mm or 5.7"

for the rear tires
max front space is ~114mm or 4.5"
max backs space is ~152mm or 6"

shorter tire and higher ride heights give more breathing room
more aggressive alignment specs give more breathing room
stiffer suspension gives more breathing room


While what you propose will be ok
it.does push the edge in front, a 7 ET25 wheel would give you a bit more breathing room by moving the whole wheel/tire assembly a bit further inboard, and an 8ET27 would be advantageous over the 7 and fit as well

In back the 255 on that wheel is a good fit but is sort of tall and wide compared to the 215 front, you end up losing ~16 lb -ft taken from the torque used for acceleration and increasing understeer.

245/35 would be a much better choice for both handling balance and torque loss

I like 215/45x17 on 8ET27 or 7.5 ET26 or 7 ET25 w/ 245/40 on 9ET15 or 9.5ET19

or

215/40 x18 & 245/35 on the same width and ET wheels but in 18

18s give a bit more grip at the cost of ride quality 17s a bit better ride at the cost of a little grip

​​​​​​​appearance is a personal quality

Bill Verburg

Here's a survey of most of the available SC/Carrera fitments the taller and wider the tire the more adjustments will need to be made to accommodate them