gatorfast

What do you mean by the front 235/35/20 is not available in Porsche spec? Tire rack has them in stock right now (the rears are actually back ordered though).

Personally, I would stick with the Porsche spec 235/265 combo over going with wider tires. The N spec tires actually have a very wide contact patch for the size and I don’t think you would be gaining much, if anything, by going up a size.

abqautoxer

As promised. 255/30/20 and 295/30/20 PS4S.

Jet Jockey

After checking my notes from the tire shops, the fronts in Porsche speced PS4S are indeed available here in Canada (Montreal). It is the rears that are B/Oed and may only come mid to late October.

You are also correct about the width on the P speced PS4S tires.

I checked out the the overall width and tread width of the wider tires and in some cases they are actually narrower than the P speced PS4S tires. The only one that is really wider is the 295 mm rear tire when compared to the P speced PS4S rear tire... here is the data I found...

Porsche speced PS4S tire for the front is a 235 and it's section width is 9.5 inches while it's tread width is 8.6 inches. A 245 PS4S has a section width of 9.8 inches but yet it's tread with is the same at 8.6 inches. The 255 tire has a section width of 10.2 inches but amazingly a tread width of only 8.5 inches.

Porsche speced PS4S tire for the rear is a 265 and it's section width is 10.7 inches while it's tread width is 9.7 inches. A 275 PS4S has a section width of 10.9 inches but yet has a tread width of only 9.4 inches. The 295 tire has a section width of 11.9 inches and it's tread width is 10.3 inches.

Also note that the wider tires can be up to 2 lbs heavier per tire.

Honestly I don't see any advantage of going wider than the OE Porsche speced PS4S tire.

Jet Jockey

Love the colour! Was supposed to be the colour of my car but because they could not give me a build/Euro delivery date, I cancelled the purchase and went with a used GTS ( which ended being the right thing to do) they had just received from Porsche Canada but the car was Carmine Red.

Thanks for the pictures with the wider tires.

Jet Jockey

Looked up some of the tire specs for the PS4S from both Michelin and the Tire Rack and came up with the following dacts/data.

There is obviously a reason why we have Porsche speced PS4S tires because their construction is different compared to the "all purpose" PS4S and the other manufacturers' speced PS4S.

Some of the specs that change are tire load, section width, tread width and weight of the tires.

For the front PS4S speced for Porsche (#08557) in a 20 inch size, the 235/35/20/XL (92Y), the section width is 9.5 inches as measured on an 8.5 inch wheel with a tread width of 8.6 inches. The tire weighs 23.1 pounds.
The front Michelin "all purpose" PS4S (#33211) in a 20 inch size, the 235/35/20/XL (92Y), the section width is 9.5 inches as measured on an 8.5 inch wheel with a tread width of 8.5 inches. The tire weighs 22.7 pounds.

For the rear PS4S speced for Porsche (#07389) in a 20 inch size, the 265/35/20/XL (99Y), the section width is 10.7 inches as measured on an 9.5 inch wheel with a tread width of 9.7 inches. The tire weighs 27.4 pounds.
The rear Michelin "all purpose" PS4S (#14196) in a 20 inch size, the 265/35/20/XL (99Y), the section width is 10.7 inches as measured on an 9.5 inch wheel with a tread width of 9.6 inches. The tire weighs 26.3 pounds.

To recap the above info, both front and rear Porsche speced tires have a wider tread width albeit by only 0.1 of an inch. However the Porsche speced PS4S are also heavier; the front tire by 0.4 of a pound and the rear tire by 1.1 pounds.

Michelin and Porsche worked together to design and create a tire specifically suited for the car most likely by either adding extra rubber at specific areas on the tire or modifying the internal construction (belts) to reinforce certain areas of the tire to get optimal performance and life out of the tire.

Before anyone jumps the gun, I know that most people don't care or will not notice the difference between the tires and I'm 100% sure it is perfectly safe to drive a Cayman on the "all purpose" PS4S. In my case I'd prefer to get the Porsche specific model because that's the way I am and intend to use the PS4S as my rain tires when tracking the car.

BTW, I don't know if the Pirelli P Zeros on my car are a one of (maybe they froze at some point), but on the track in the wet they are some of the worst tire I have ever driven. The car doesn't stop and won't accelerate especially out of corners where wheel spin even in fourth gear in slow corners can have exiting moments.

David Borden

Nice looking car! Those wheels look great, can I ask what they are?

David

abqautoxer

OZ Racing Hyper GT HTL

sobiloff

I'm afraid your info is out of date:

X2Board

Which website is this screen shot from? I just checked Tirerack, and they don't show an N spec in that size.

Ray831

Guys, while we are on tires, is N spec really that important if you are not going to track your vehicle?

Jet Jockey

Like I said in one of my previous posts, you can surely be fine with the regular “all purpose” PS4S tire but you will not get the most performance and wear characteristics of the NA0/Porsche specked version.

I would not buy the Mercedes or Tesla specked version.

gatorfast

Its not really about tracking your car but rather using tires specifically designed for your vehicle. Normally, a 235 tire is a little wide for an 8" front wheel and a 265 tire is a little narrow for a 10" rear wheel. But the N spec tires are designed to fit these wheels and have tread patterns and contacts patches which maximize grip. N spec tires are only a few more bucks compared to their generic counterparts so to me its a no-brainer.

Jet Jockey

Correct!

I'll add that it even goes further in that tire wear is also considered when designing the N tires.

I went to a specialized tire information session two years ago and one of the subjects that came up was the "manufacturers' specific tires". Basically and for most of the talk that night was around the Porsche cars and their specification tires. The host went on to explain that when a car manufacturer like Porsche decides to make a spec tire, they sit down with the tire manufacturer to design a tire that meets the best performance criteria and wear factor for the car. The construction or "inner guts" of the tire can be substantially different then the "all purpose" version of the same tire. They take into account the type of car and the suspension geometry (toe, camber, wheel offsets, etc.). This will in turn perhaps change the rubber compound, where more rubber is needed, where and how the steel belts are used etc.

He went on to say that with today's high performance cars (like a Porsche) that request a spec tire, you have to treat this tire which comes with its own part number as a car part number... In other words you would not buy a Bilstein shock for your Porsche from a Toyota dealer even if it were the same size/fit as the one on the Porsche.

abqautoxer

Do you actually know the targets for that exact tire? I see these claims all the time but knowing how the tire industry actually works, that usually isn't the case at all. It certainly COULD be the targets for that tire but N spec by itself doesn't guarantee that at all as it's per application.

Ray831

Thanks for the education guys. Ill stick with N spec tires.