Michelin tyres on the 992 C2S

[barry-d5ytf]

Standard tyres on a 992 C2S are 245/35 ZR20 with 305/30 ZR21, OEM options are P Zero or Goodyear Eagle.

I can find Michelin PS4S - 245/35 R20 (95Y) XL (N0) TL – BUT ONLY FRONT TYRE AVAILABLE, NO REARS.

But on my 992 C2S spec sheet (last page of the PDF) I see bigger sized Sports tyres at 265/35 ZR 20 and 325/30 ZR 21. What are Sports tyres and do these fit the standard 992 wheels?

For example Michelin PS4S tyres are available as follows:
• 265/35 R20 (99Y) XL (N0) TL
• 325/30 R21 (108Y) XL (N0) TL

[Filibuster]

barry-d5ytf said:

Standard tyres on a 992 C2S are 245/35 ZR20 with 305/30 ZR21, OEM options are P Zero or Goodyear Eagle.

I can find Michelin PS4S - 245/35 R20 (95Y) XL (N0) TL – BUT ONLY FRONT TYRE AVAILABLE, NO REARS.

But on my 992 C2S spec sheet (last page of the PDF) I see bigger sized Sports tyres at 265/35 ZR 20 and 325/30 ZR 21. What are Sports tyres and do these fit the standard 992 wheels?

For example Michelin PS4S tyres are available as follows:
• 265/35 R20 (99Y) XL (N0) TL
• 325/30 R21 (108Y) XL (N0) TL

Can't help you with your specific question, but I was staggered to see how big these rear tyres have become

325/30 R21 !!!!!!!

And I thought my 295/30 R19 (also shoed in MPS4S, great tire btw) where huge already. This takes it on a whole new level.

[Koln-RS]

The statistic that is never shown, but would most interest me, is the weight of individual wheels and tyres.
Big fan of the benefits of ‘unsprung weight’ saving - and these ever bigger wheels and tyres must have a negative effect.

[Orangecurry]

You must have seen this?

http://www.944racing.de/wheelweights.php

Big thanks to Florian Seibold, who collated all of this research for the older wheels and some tyres, but nobody has done it for the recent generation of wheels/tyres.

Maybe the new ones are too big and heavy for normal weighing scales?

[STiG911]

Hi
I've downloaded the PDF Brochure for the 992 C2s and can't fine those tyre sizes anywhere - do you have a picture of that page so I can see what you're talking about, please? It'd help to context where you're seeing this info.

However, from what I've learned on my experience with cars in general, I'd be very surprised if that much of a tyre size increase either fitted the standard wheels, or the car, or both.

Firstly, I can't see how that much extra rubber would fit the standard rim width. As an example, your wheels are 8.5in wide accepting a 245 tyre, but the 992 Turbo spec says it has a 9in wide rim accepting a 255 tyre, so putting a 265 tyre on a 8.5in wide wheel would not be advised.

Secondly there's the question of offset. Any tyre size that large on a 992 will almost certainly require a different offset to move the tyre further away from the hub to avoid contact with the body under compression. Insofar as I'm aware, the only car with those larger tyre sizes is the 991 GT2RS.

[Koln-RS]

Orangecurry said:

You must have seen this?

http://www.944racing.de/wheelweights.php

Big thanks to Florian Seibold, who collated all of this research for the older wheels and some tyres, but nobody has done it for the recent generation of wheels/tyres.

Maybe the new ones are too big and heavy for normal weighing scales?

That’s a very interesting link.
Unsprung weight saving is credited with a lot of dynamic benefits - improved performance, handling, ride, braking, steering feel.....
And, I was once told that 1kg of unsprung weight saving was equivalent to 5kg of sprung weight saving.

[Orangecurry]

I read it was x4?

But a big difference regardless.

That's why I have tried so many many OE wheels. The lighter ones really do make a difference.

[barry-d5ytf]

Apparently sports tyres = GT3 RS/GT2 RS sizes, and a C2S has 11.5 inch rear wheels, too narrow for those sizes.

When you configure a C2S and save it as a PDF the last page includes sports tyres as well as standard tyres...

So we will have to wait for a 21 inch MPS4S!

[Orangecurry]

Apologies to the OP for going off-track slightly....

Koln-RS said:

That’s a very interesting link.
Unsprung weight saving is credited with a lot of dynamic benefits - improved performance, handling, ride, braking, steering feel.....
And, I was once told that 1kg of unsprung weight saving was equivalent to 5kg of sprung weight saving.

Spookily today I was doing some tyre research, as you do, and noticed that some of the industry testing is including tyre weight for the first time.

But my question would be 'does a lighter weight tyre have a softer tyrewall?' I often ask myself such questions.

https://www.tyrereviews.co.uk/Article/2020-UHP-UUH...

Thanks to Jon for this info.