987.2 - CS - 6MT - Wider Tires Possible? - Forgeline Wheels

Hello Planet-9 family! Here goes my first real post... I am purchasing Forgeline Wheels for the 987 CS - 6MT - which will be lowered on Cayman R suspension in the upcoming months. The car is driven in Long Island but I sometimes venture to the city a few times a year if the weather is right. And unfortunately this car will not be going to the track. The specs for the Forgeline Wheels are as follows: Front Forgeline VX1R - 18 x 9 ET 47 offset - Proposed Tire Size: 255/40-18 Rear Forgeline VX1R - 18 x 10 ET 35 offset - Proposed Tire Size: 285/40-18 I really want PS4S ' tires as I have been a big Michelin guy for a while and don't need a dedicated track tire. I also understand that with more sidewall, the feel is a little less numb which is a sacrifice I am willing to make. I also prefer sidewall protection because as you are aware, the roads aren't always in the best condition in the Northeast and I want to protect my suspension and pricey wheels as much as possible. Thank you all for your input, I appreciate it! Omair

Omair, If you are going to use the 40 side wall, I would highly recommend you use a tire with a lot of spring rate, RE71RS. This is Bridgestones new model for the Street. Its fast and sticky. Also works extremely well in the wet. Not standing water though. This tire would do wonders for your car Here is a video of the Cayman vs Toyota on the street. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjH0YKP0sL8AhXdATQIHQvWAQgQz40FegQIJRAs&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DRNMBFGCWR1E&usg=AOvVaw2HG-BzobGKAcqAix6PgPqM

Are you suggesting the 40 series sidewall will work? I saw you raving about the RE71RS' in another thread. I am reluctant as I do not need an aggressive 200TW tire. I do however like Bridgestone as a brand.

They are robust and have grip. I had the older model RE71R and drove them on the street for about 7500 miles. During that time I had a bolt go into the face of one of the back tires . Took it to my tire shop had had them put a patch inside as well as plugging the bolt hole. This tire worked well until all 4 tires were at their wear bars. Great tire. If you want the tire side wall to soak up some of the road noise and vibrations, the Michelin PS4 's will work fine in a the 40 side wall models. I just think that stiffer side walled tires are better for turn in and control of the surface tire patch rubber. The tire bead and side walls are the foundation which the rest of the tire is built on. After your install, take a few pictures so we can see your work. Add any comments on how they ride, turn in, NVH, and stopping,

Michelin PS4 's come in 255/40/18 f and 285/40/18 r. You are good with setup.

Yes I am aware they come in that size but will this setup work and fit in the wheel well with the above wheels with their specific offsets?

Well I have these tires in 35 side walls vs 40 you are requesting and they fit fine. Maybe some other owner has exactly your setup, but mine is close with two sets of forged wheels with your setup. so you will need to figure out if the sidewall makes much difference. Again, my PS4's are in my garage against the wall and have been there for 2 years due to another tire being much more aggressive and fills my needs better. That tire is RE71RS now. Even the newest PS5 will not check all the boxes that these tires do. They are cheater summer tires .

Omair, The OEM tire size is 235/40/18 f and 265/40/18 R. So yes the 40 side wall 255 f and 285 will fit. If you find slight tire rub in front on the spring perch on full lock, just get a 5 mm spacer to push the wheel out slightly. Not sure as I have not run 40 side wall tires for 5 years and the 47 offset moves the wheel/sidewalls closer to the spring.

On my 07 Cayman I have 235/35/10 front, and 275/35/19 rear, my car is at stock ride height. Just eyeballing things with the car 20mm lower, and tires a few mm wider it may be close... Note that same size tires from different manufacturers can actually vary, a Conti may fit, a Michelin may not... I don't remember the offset of my wheels... I'd have to pull them to measure and verify..

I have 245/295 setup lowered. Offset very flush and no rubbing, I’m on Apex 601 tires . As good as PS4’s but not as good at the RE71’s 19x8.5 +43 19x10 +25

What's the size of your sidewall and what suspension do you have? Can you share pics?

Looks amazing! Let me plug your wheel specs into the calculator online to see if I can push a 40 series sidewall.

When you go 295 and up need to drop sidewall Example : 245/40/18 and 295/35/18 I have 285 not 295… sorry about that I’ve tried 295 and even a 305. 305’s you start to understeer and have that push feeling… 295 was okay tho. Watch the brake lines, very close imo and would need to be zip tied offset depending Below: 285

pinincoff- If you have custom LCA's to give more camber to reduce outside tire shoulder wear, you will need to add the shim dimensions to the wheel spacer for the correct track width on each axel. Not including this measurement could give more track than you want, resulting in tire rub on the fender arch. This is only if you have aftermarket LCA's.

Thanks Apex1! My CS is stock. I was just curious what it would take to replicate the stance of Porsche08 CS.