996GT3 trackday tyres – standard MPSC2 vs going wider

[BrendonJ]

All,

I have a 996.1GT3. The wheel/tyres combos are apparently:
Mk1:
Front 8J x 18 ET52 with 5 mm spacer 225/40/18
Rear 10J x 18 ET65 with 5 mm spacer 285/30/18
Mk2:
Front 8.5 x 18 ET40 235/40/18
Rear 11 x 18 ET63 295/30/18

I understand you can run Mk2 wheel/tyre sizes on a Mk1.

My question is tyre width. It will basically be used just on track so I’m only interested in trackday tyres (MPSC2, R888R etc). A few of the US boys are running wider tyres on theirs (315/30 and 255/35). The only trackday tyre in those size combo seems to the Yokohama Advan A052 Tyre. I don’t much about these tyres, would it be better to run the wider A052 than the standard size MPSC2?

Is anyone running any other wider combos?

Many thanks,
BJ

[SignalGruen]

Can't help with your size question but I run Mk2 GT3 sized MPSC2 on my 964. I would like to switch to AO52 next since they offer a 295/35 tyre - I would be interested to know how these tyres compare to the Cup 2's if you go with these.

[Steve Rance]

BrendonJ said:

All,

I have a 996.1GT3. The wheel/tyres combos are apparently:
Mk1:
Front 8J x 18 ET52 with 5 mm spacer 225/40/18
Rear 10J x 18 ET65 with 5 mm spacer 285/30/18
Mk2:
Front 8.5 x 18 ET40 235/40/18
Rear 11 x 18 ET63 295/30/18

I understand you can run Mk2 wheel/tyre sizes on a Mk1.

My question is tyre width. It will basically be used just on track so I’m only interested in trackday tyres (MPSC2, R888R etc). A few of the US boys are running wider tyres on theirs (315/30 and 255/35). The only trackday tyre in those size combo seems to the Yokohama Advan A052 Tyre. I don’t much about these tyres, would it be better to run the wider A052 than the standard size MPSC2?

Is anyone running any other wider combos?

Many thanks,
BJ

I'd stick to the smaller tyres, you wont get much performance gain on the lap with the bigger ones - unless there is a cost benefit.

I have experience with most tyres/compounds in GT3's. The problem is that big and relatively heavy GT cars work thier tyres quite hard and as a result they can go off quite quickly. If you are quick, they will go off even quicker. If you leave something on the table, it's not so bad. I could never get more that one or maybe 2 flying laps out of a Toyo for example. After that, they went off quickly.

Personally, i'd still go for a Mich cup but even these dont hold on like the original compound. You may get 4-5 laps before you need to come in and cool them. For consistancy and pace, they are still my default non slick option. If you are quick, you may get 3-4 days out of a set of rears and 4-5 days out of a set of fronts which in terms of wear is much better than the original cup 1.

[nxi20]

I agree with Steve, there's not a lot of advantage to going bigger on 18". I run 245/35 & 305/30 on 19" rims because they're easily available, but mostly use 235/650 & 285/660 slicks on 18". As to tyre choice, I have found the Pirelli Trofeo R to be a really excellent trackday tyre you can drive on the road; probably as close to the MPSC of old in terms of heat stability & grip. They're expensive though!

[BrendonJ]

Thanks for the replies. Very good point re quality of tyre and heat cycles.

MPSC2 is (was?) the best trackday tyre. However I am hearing (as the above) that this Trofeo R is even better. Trouble is it doesn’t come in 18” sizes.

So it sounds like the advice is stick to the standard size MPSC2 rather than the wider/unknown quality tyre.
However I’ve just noticed the R888 can still be purchased in the 255/35 (from Tyreleader) and 315/30 (Demontweeks). That is old tech now but again an interesting possibility.

If I run a 255/35 315/30 combo will they stretch onto the standard 8.5” ET40 and 11” ET63 (mk2) wheels, or will I have to go to a 9”/12” wheels? What offsets will those 9”/12” wheels need to be? I’ll be ordering some OZ Allegritas so should be to order those in the required offsets.

Many thanks

[nxi20]

BrendonJ said:

Thanks for the replies. Very good point re quality of tyre and heat cycles.

MPSC2 is (was?) the best trackday tyre. However I am hearing (as the above) that this Trofeo R is even better. Trouble is it doesn’t come in 18” sizes.

So it sounds like the advice is stick to the standard size MPSC2 rather than the wider/unknown quality tyre.
However I’ve just noticed the R888 can still be purchased in the 255/35 (from Tyreleader) and 315/30 (Demontweeks). That is old tech now but again an interesting possibility.

If I run a 255/35 315/30 combo will they stretch onto the standard 8.5” ET40 and 11” ET63 (mk2) wheels, or will I have to go to a 9”/12” wheels? What offsets will those 9”/12” wheels need to be? I’ll be ordering some OZ Allegritas so should be to order those in the required offsets.

Many thanks

Not sure why you think the Trofeo isn't available in 18"; I would stick with standard sizes personally. I've tried 255/35 on a 19" & it caused more problems than it was worth tbh.

https://www.tyreleader.co.uk/car-tyres/pirelli/pze...

https://www.tyreleader.co.uk/car-tyres/pirelli/pze...

I use 9" OZs on the front. Think they're a Boxster rear fitment with an ET of 43 or so.

[Digga]

BrendonJ said:

MPSC2 is (was?) the best trackday tyre. However I am hearing (as the above) that this Trofeo R is even better. Trouble is it doesn’t come in 18” sizes.

FWIW and to back up this and the advice from nxi20, Mike from Sports & Classic fitted a set of Trofeos on his 996 GT3 CS before the RS track day at Oulton earlier this year. His default was to go back for another set of MPSC2 but couldn't find any at the time so tried the Pirellis. He seemed to be impressed with them, certainly wasn't hanging about.

[BrendonJ]

Nick, thanks for that, I must be going blind.

PS Why the 9" on the front if you are running the standard tyres sizes, wouldn't that just result in a heavier front wheel (vs the std 8.5")?

[Slippydiff]

I've run 235 Cups on standard 8" Mk1 fronts with no issues. I've also run them on 9" LM's, the LM's looked pretty, but didn't do much for the steering feel because the LM's were all additional offset with little inset to compensate.

235 Cup 2's on 9" LM's :



235 Cup 1's on standard 8" rims :

[nxi20]

BrendonJ said:

Nick, thanks for that, I must be going blind.

PS Why the 9" on the front if you are running the standard tyres sizes, wouldn't that just result in a heavier front wheel (vs the std 8.5")?

The weight difference is negligible. The 9" is a better offset & means increased track without using a spacer. Personal choice of course, but I prefer this over stock.

[Steve Rance]

Agree with earlier posters. Pirelli also a good choice. The Cup used to last longer before going off. The Slip angles increased with Pirelli but they were predictable. I do not have experience of the new Pirelli so I can't advise