johnhemp

Hello. I have just joined Rennlist and am very impressed by all the special knowledge and willingness to share it. I have an '06 Cayman S I am totally in love with, 63 years old and never had a sports car. The tight feel on the road and taking curves is awesome, and I want to up the performance. I have searched all the forums and can't find anything, so wanted to ask this question:

I have the 18" 5 spoke Porsche wheels on my car, and now have Michelin Pilot Super Sports, 235/40R18 front, and 265/40R18 rear, the sizes Porsche recommends. I am thinking about using a new wider set of Super Sports on the same wheels, 245/40R18 front and 275/40R18 on the rear. Can anyone tell me how the wider front tires will affect handling? I am going to upgrade to the Bilstein coilovers that fit the Cayman, also, that plays in the mix. I think I am OK with the wider rear tires, but again would welcome any advice/opinions from any of the experienced members. I have tracked the car, but don't any more, can't stand to tear up the car. But I like to drive like h____ and it is my daily driver. Am set up to get the EVOMsit RS 350 package for more horses, and want tires that will work well with that.

Thank you anyone for your experience and opinions. I didn't find a thread on this when I searched, but it there is one, please post the link. Thanks again. JH

ADias

Why are you after wider tires? Wider tires (assuming front and rear are in balance with each other) will make the car less fun. Grip should match the car power and a modest retune will not require larger patches. The car may grip better but will it be fun? IMO, Weissach knows best.

johnhemp

Thanks for responding? Why "less fun"? Slower car, poorer cornering, different feel, I'm not sure what you meant. The rear wheels spin if I completely floor it at a standing stop, and they have plenty of tread on them. That is what makes me think, with a 15% or so power increase, the wheels will just spin more.

ADias

A Porsche is all about smoothness in driving. Smoothness means momentum conservation and speed. Smooth application of all car controls (throttle, brake, and steering). Porsches are not burnout machines. Today's cars already have plenty of grip. Add rubber and they stop dancing.

Adding rubber in an unbalanced way may be bad too safety-wise. Before you mod the car, I recommend you join PCA, participate in autox and/or DE events, learn from a driving coach and learn the car first.

San Rensho

Common wisdom for these cars (Box/Cay) is to get wider tires in the front to reduce understeer, along with dialing in more neg camber in the front and reducing neg camber in the rear. Many people on the track run a square set up, same size tires front/rear.

Bill Lehman

If you're not tracking the car, wider tires should never have an effect during street driving as you should never approach the limit of the factory sized street tires.

GT3 Nut

John, those size tires will work just fine. True that it is probably not necessary to get wider but they will work just fine. The difference in size between the front and rear will be the same as factory sizes. I have 245 from and 275 rear pilot super sports in the 19" size on my Spyder.
The comment about not going to the track anymore because you don't want to tear it up. You might reconsider that notion. These cars are built very well. Mild to moderate track use will not do any harm. And it's the safest place to explore the limits of the car and enjoy it for what it's meant to do - handle well. Not a drag strip car.
Either way have fun and enjoy it.
By the way, I went with the wider size street tire just for aesthetics. On the track I also use a wider tire but that's for better grip in the corners.
However the car will be no less fun by any stretch of the imagination going slightly wider.

fhp911

I agree with the general sentiment here -- you will get NO performance advantage from wider tires since the car already has superb handing and tremendous grip in its stock form.

The Michelin tires are tops in the market already. You might want to go to a local Porsche race shop and get a high-performance street alignment.

And I agree with the poster who says that you should reconsider your aversion to the track. TAKE THE CAR TO THE TRACK; THAT'S WHERE IT REALLY SHINES.

johnhemp

Guys, thank you so much for all the information, and things to consider. I have been to a couple of DE's, so I do know how to not kill myself driving fast and taking corners. Will probably go again, once a year or so, since we now have a new Formula 1 track in Austin, just 200 miles away from where I live in West Texas. I know what I want to do, now.

This is a really good forum. Lots of experience and good feedback. I am going to "lurk" here a lot, and if I can actually contribute something, I will. Thanks.

robmbush

I've been looking for someone running this wide of a tire set on a 2006 Cayman S and would like to confirm that it works and fits like a champ and keeps very close to the original diameter (- 1.5%) and bias ratio.

Tires are Michelin Pilot Sport Super Sports in 285/35 R18 Rear and 255/35 R18 Front on BBS RS-GT 18"s

18 x 8.5" front with a +56 ET +7mm spacer
18 x 9.5" Rear with a +48 ET + 15mm spacer
I'm also running KW V3 coilovers on the car.

Enjoy:

SKeijmel

i am thinking about

oz alleggerita
8.5J 18 et 53 steek 5x130
10J 18 et 40 steek 5x130

Pilot Super Sport Sizes
245/40 R18 97 Y
265/40 R18 101 Y

bigger fronts too kill the understeer and also they can supply 235/40/r18

haripin

Reviving this thread. I have a 987.1s. Any issues with having 235/35/19 in the front and 295/35/19 in the rear?

The previous owner put 19" wheels on the car and the smallest I can go on the rear is 295 now.

hueyhoolihan

a car optimized for track or for racing is entirely inappropriate and not enjoyable to drive on public roads. i'd start from that premise and work backwards towards your goal.

A1Aflorida

For our former 987.1 (08CS), at the recommendation of the indy shop owner, we installed 235/40ZR18 front and 285/35ZR18 rear.
To me, there were two benefits: 1 - Aesthetics - The wider rear tires. especially, filled out the wheel wells so much better than the previous tires. A big improvement in looks. 2 - Track performance - To me there was a noticeable improvement on the track.
If you are not tracking, no need as in the previous posts. Aesthetic-wise, imo it will be worth the upgrade if that is important to you.

haripin

Thanks! Helpful!

if I go with 235/35/19 and 295/35/19, will I lose any handling performance on the street?

what about going to 245’s in the front with 295’s in the rear?