Wheel Offset 996.1 Narrow Body

Currently on my 996.1 my aftermarket rear wheels are an 18x10 (with a 52mm offset). With my coilovers adjusted they sit nice and almost flush with the fender line. I�m considering going to a lighter wheel set up. The rears will still be 18x10, (but the new offset will be 65). With this new setup, it will move the wheel inward .05� roughly. If I were to increase the overall tire width 1� more, would this allow me to make up the half inch lost on the outside wheel well area? (1� overall increase, .05� increase outer side of wheel well .05�increase inner side wheel well?) (That means going from a 265/35/18 to a 285/35/18 to accommodate the offset) +1� greater tread width Also, there should be no issue with sidewall height remaining the same I�d imagine thanks guys, the whole suspension geometry always makes me scratch my head a bit.

I think u r gonna want to put a 5-8mm spacer on there. They should fit without one so i would just mount them up and see how they look. Also a few other factors come into play like ride height, camber setting and if u rolled the fender lip.

Thanks for the tips on everything. My ride height is probably 1.5”-1.8” lower than factory H&R coilovers, the camber (that I am aware of, from my shop who set up my suspension) is that it is on its max negative that can be achieved still with the stock control arms. With the current rear offset, and 265 tires, it seems to tuck right below the non rolled fender, so it is a little tighter currently. Maybe some of that can help further explain what I’m looking at here. Thank you for the info

Well my rims r gt3 spec if u want to do the math. They were a 18x11 et 63 with a 295. My car was pretty low and i had the camber at 2.5* and fenders rolled. It all fit fine. Now im at gt3 height and 3.5* camber with a track tire thats a 305 on a 18x11 et 60 apex. Both sets fit fine with the new coilovers.

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Appreciate the reference. Are your 295�s a 30 side profile?

Yup 30. This is the track set up at 3.5* vamber.

Thanks again for the reply. After doing my math- I believe I can squeeze a 285/30 on the rear, not have to roll fenders and still achieve roughly the same placement of the rear tire in the wheel well. I will just lose a little sidewall height

FYI, this is what wheel/tires off a 996 widebody (turbo, C4S) look like on a lowered narrow body C2 w non-rolled fenders

^^^Need some “spinners” on there...

That’s a lot of tire going with the widebody set up. The 18x11 vs 18x10, will certainly fill the wheel well a decent amount more. I’d imagine the backspacing on the above are somewhere like 52-54mm offset also?

Wide body et is 40 on an 11" rim. Narrow body is et 60-63.

Try this website. https://www.wheel-size.com/calc/ You can key in your current wheel/offset/tires and the proposed ones. This is especially helpful as you can measure clearance on the known set up, under load and the website will show you the difference.

I have 18x10 +65 sport classics on mine now with 265/35/18's. Here is how it looks. I am hoping this winter to keep my current set but pick up a set of 17's to run more tire. 17x9.5 +45 in the rear but will probably need to run a 15mm spacer as well

left field idea put big lips on those classics

Are they a true 3 piece wheel? I don't even know lol

No they are not 2 piece nice rims though classic look and they look like they are right in the side view shot Mike

looks like 2 piece, so take the faces off, put big chromed barrels on them bag the car smash your oil pan

Appreciate everyone�s input, I�ll actually be able to squeeze a 295/30/18 in my car with my current suspension set up (H&R coilovers, fairly aggressive camber etc). The 65mm offset on the wheel that I�m now running will allow me to squeeze the slightly larger tire without fender rubbing. The 285/30, overall diameter is a little to small which would leave a reasonable amount of fender gap, the 295 will fit perfect.