Carpokes Porsche Forum

From my old 987.2 Cayman S I have several sets of 18" wheels for autocross and track day tires.

One set are O.Z. Racing Alleggerita HLT 18" with 8.5" up front and 10" in back.

The tires I'm looking at are the same as stock: 235/45-18 in front and 265/45-18 in back.

The rears are 10Jx18H2 ET40. From what I can tell, those are fine.

The fronts however are 8.5Jx18H2 ET53 and those are the ones I'm not sure about.

If I bring up the 987.2 in the TireRack wheel configurator thing:
https://www.tirerack.com/wheels/results ... ard+Brakes

Those wheels are available as an option with 8.5x18 ET53 in front and 10x18 ET40 in back.

But when I look at the 718, there are no 18" 8.5 wheels as an option, at all:
https://www.tirerack.com/wheels/results ... toModClar=

It does appear to support 8x18 ET57, but the only 8.5 options force 19" or 20" rims.

For 19" 8.5x19 ET53 is an option.
For 20" 8.5x20 ET50 or ET55 are available.

I'm confused why 8.5x19 ET53 is an option but 8.5x18 ET53 is not.

With the base model 718, 18" wheels are an option at 8x18 ET57 but I'd like to know how much trouble I'm going to have with the 8.5x18 ET53 or if there is some clearance issue that makes 18" 8.5" rims a non starter?

There has been some discussion on Carpokes about whether 18" wheels are ok for 718 Base, S or GTS models. They cannot (or should not) be used on 718 GT4s due to clearance issues (calipers) but some widths of 18" wheels should be ok on non-GT4 718s.

Here's one thread:
viewtopic.php?t=2178#p22791

Apex Wheels (which several of us here use and prefer for track) list certain of their wheels as ok for non-GT4 718s. Some 18" wheels will fit directly while others call for some alterations such as a spacer for the rear to clear the struts. Anyway, Apex has some info at this link to get you started on possibly finding an answer. (They list available tires that will fit a particular wheel of theirs which also might be of some help.)
https://apexwheels.com/fitment-guides/p ... ment-guide

@J-Dub and @WillyDaP will also be able to help with your questions.

I have both 19 inch and 18 inch Apex wheels with 9 inch fronts and 10.5 inch rears. I prefer the 18s as it gives you more choice on tires, yet there is a concern about tire size in relation to the diameters. The 718 needs a smaller diameter in the front than in the rear, so this can make what appears to be an easy search for tires more complicated when one thinks they found a solid set of rubber. Apex does have a pretty good chart concerning tires that fit, so follow that though there are a few situations where they may be incorrect. Those not wanting to use wider tires will likely have fewer concerns. One runs into concerns because a bigger or equal tire up front could cause the tire to go in " Ice Mode " under heavy braking so you want the front rubber to run a bit faster than the rear to alleviate this concern.

Hey @Throttlesteer I see your post about the same wheels with your GTS 4.0:
GTS 4.0 Tire-Spring Rubbing Issues - viewtopic.php?t=1855

Did you end up finding a solution?

With the 987.2 I ran 7mm spacers in front and 12mm spacers in the rear. The rear ones will fit the 718, but the front ones are the 3 finger hub so I was considering getting new ones to push the front wheels out a bit.

I'm very curious about your experience with the GTS 4.0 and these wheels.


Thanks for the other replies.
@WillyDaP I had similar issues with the easily sourced tires for my 987.2 and did have a few wheel sets that triggered the PSM failure if the fronts were not sufficiently smaller than the rears. For the application at hand, I'm confident the overall diameter and rake is fine.

@blueline I had seen that Apex page before and it seems like they go for the 9" wheels up front and the only mention they have about 8.5" at all is to say:

Most notably, these fitments incorporate wider 9” front wheels which provide superior tire sidewall support over the more "generic" 8.5" front wheels typically found on a 718.

Which is interesting since the modest research I've done so far does not reveal 8.5x18 as a common size suggested for the 718 at all.

I had a 2019 718 Cayman GTS [2.5T], and used 18" OZ Alleggerita HLT wheels for track and autocross. They fit without any problem. Note: The GTS 4.0 has larger rear brakes for sure, not sure about front brakes, so it may or may not fit the GTS 4.0.

Front: 18x8.5 ET53
Rear: 18x10 ET40