Ryan968

Hey guys,

About time I start posting as I'm finally beginning a new project 968! I'll start a thread and work on keeping everyone updated on progress as I go along.

Anyway, I'm ordering new rims from HRE, and could use some advice on ET since they're built to spec. I've read several threads on the subject and there seems to be quite a variation on what is best or will work. HRE wants me to run 235/40 18x8.5 ET55 and 265/35 18x10 ET55, and won't suggest anything outside of that. I know a lot of you run 225's and 285's with various ET's without any issue or having to roll fenders. This is a turbo build but not a dedicated track car, and I'd like to run a 285 for sure.

My dealer and I are thinking we can push the offset a little too, as a lot of the pictures and previous posts look to have or mention more fender gap then ideal. We are thinking to run, 235/35 18x8.5 ET50 and 285/30 18x10 ET50. The goal being to get a nice flush look without any rubbing and push the tire width. This combo looks like it might be the sweet spot any thoughts? We've also looked at a 225/40 and 295/30 tire combo as well, debating on overall height of the two vs stock. Do you think ET50 will work without any problems on one of those tire combos, or should we stick with ET55, or some other offset??

Thanks for the help, and look forward to getting to know everyone here!

Trueblue

Ryan968

Thanks for the response, and appreciate the thoughts and idea to look more into some OEM Turbo specs!

Goals are handling and appearance first, then ride quality. I will be running GT3 6 piston brakes up front, and Intrax RSA coilovers (purchased but not installed other than brakes for test fit and measurements for HRE). Problem is I want to wait on install until after paint, so right now I'm becoming quite the parts hoarder until I find time and place to pull the engine lol.. Plus once I install suspension and brakes, I can no longer fit my factory 16" rims, so measurements get tricky anyway at that point.

I'm not worried about ride height (or fender gap in that regard), as I can easily adjust via coilovers, but the offset is of concern and getting the in/out placement right. Plus the two tire combinations I'm looking at are the same or smaller than factory diameter, which I'm told is 636mm or basically 25". But using my factory measurements aren't getting me there. I'm hoping someone out there can say max ET or perfect look w/ 18x10 285 or a 295 without modifications is ____ based on their experience or trial/errors. I really don't want to order custom rims that have clearance issues, or still need a spacer to look just right.

Since I really like the look of the HRE's, and they custom build, I thought it would be a great way to go as I want a nice flush look to the fender within reason and without rubbing. I know a bunch out there run Speedlines or Carrera 5 spoke 18's but you just get the offset that they are and maybe run a spacer if you want to push them out some. Here I can choose where to put them. I did a full measurement sheet for HRE, but I know they are being conservative in rear tire width at 265 and maybe placement too.

From some old posts I've read here, my guess is ET 55 would be fine, but ET 50 might be a perfect fit. However, I don't want to go too far and have to modify the fenders.

Sorry for the winded response! Thanks again for the thoughts.

Ryan968

So after looking around on here more, I'm thinking to go with:

235/35 18x8.5 ET55
285/30 18x10 ET55

I think this is a safe combo from what I can tell and should look good too (even if I could push them out a little more). Plus the dia is smaller giving me a little more room to adjust ride height and suspension.

Any thoughts?

Davito

I wonder if you will get understeer with such a big difference (235 vs 285). I'm using 255 front 275 rear on 17" with no rubbing on my S2 and I love the balance. If I had to buy wheels again I would probably do 255 in all four corners. I also have Intrax RSA coilovers

Jay Wellwood

From my 968 notes-

968 Turbo S - Front 18x8 ET 52 with 235/40. Rear 18x10 ET 61 265/35
968 Turbo RS - 18x9 ET 57 265/???. Rear 18x11 ET 62 305/??

Sorry, that's all I have to offer.

Ryan968

I'm sure you're right that I'll deal with some understeer with what I'm thinking, and a more square setup would probably be more ideal. I didn't know it was possible to run 255's without fender modification, do you remember what your offset is? My thinking on pushing the rear width is due to me adding the turbo. I guess if I end up spending too much time at the track I could just get another set of rims for a track setup (and maybe ones that aren't so expensive lol..) How do you like the RSA's, and did you keep your torsion bars?

Ryan968

No thank you very much! I was looking and had found part of that but wasn't totally sure, like when I saw the 18x11, I just assumed that was an error.

Ryan968

I had actually run into an old post of yours about offset and running an 18x10.5. PorscheG96 had mentioned running a spacer on the Speedlines per a suggestion of Raj to move it out to an ET53. Did you end up going that direction with the 10.5, and if so what offset and tire did you use? Thanks for the help Jay (old and new)!

Jay Wellwood

Not yet...

Davito

RSA is great, no torsion bars. But mine is a very stiff track car, so I don't know how it will be for a car the sees some bumpy road use. Another big improvement on handling was aftermarket control arms, if you plan to lower the car need control arms that allow to correct the center of roll.
The coilovers have a much smaller diameter than the factory struts, that allows to fit a wider wheel. I don't know the exact offset of my current wheels, they are 3 piece 8 1/2 x17 but according to my measurements is about ET50. The back space is 6 1/2.
I have test fitted a 9x18 ET 52 on the front of my car with no problem, the wheel PN was 993.362.138.01.
I found this website very helpful https://www.wheel-size.com/calc/

Again this is for a 944 S2, please check if 968 is the same.

Good luck with your project!!

Ryan968

Thanks for the info and sounds like you have a nice track setup! We'll see where this project leads.. I'm building it as a street car that will see some track use, but my fiancee wants me to build a dedicated track car. Who am I to complain! However, once all the receipts come in for this one I'm sure there will be some concessions to see a second build lol

Just ordered the rims! Left them at ET55 but changed the tires slightly due to availability- 235/40 & 285/30. Pictures and fitment notes in a couple of months.. Figured I can order something else just for track use if I want to run a square setup. Thanks to everyone for the help!

Davito

Looking forward for those pictures, never seen HREs on a 968.

James G.

https://www.1010tires.com/Tools/Whee...et-Calculator#
That website will come in very handy. You can plug in your known wheel and see what happens when you change the ET and width.
I would avoid the 285/30/18s. Not many options for tires. Consider 295/30/18's in the back and 255s or 265's in front. A 235 is to small for big back tires.

James G.

Tell me more about the GT3 brake set up! What rotors? What are you using for an adapter to bolt them up?