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Handling in one word
The car was designed for a non square set up and the larger rear than the front still give the driver far more feedback than the square set up. If just for shopping or cruising without excessive speed, then square is fine, but any enthusiastic driving requires the 275/305 set up.
This only my opinion of course!
 

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+ more hassle with a puncture on the 275/305 setup. With the square setup you only need one keep one spare handy. 275/305 supply seems iffy at times. As John says, depends on your priorities....
 

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Discussion Starter #5
My plan is to replace with MPSS and keep my Dunlops for track day as there just about legal.

Think I would prefer the 275/305 set up as when I'm on lates the roads are empty when I come home so most of the time have a little play.

What are the profiles of the 275/305 setup cheers
 

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My plan is to replace with MPSS and keep my Dunlops for track day as there just about legal.

Think I would prefer the 275/305 set up as when I'm on lates the roads are empty when I come home so most of the time have a little play.

What are the profiles of the 275/305 setup cheers
I had the bridgestones on when I bought the car, for 2 weeks! lol and was wondering why I couldnt get the power down in the wet, great in the dry tho.. rear end was very twitchy when pushed

so got the mpss, a lot better in the wet, and with the staggered setup, a lot less twitchy when pushed

Michelin pilot super sport MPSS

275/35ZR20/XL 102 (Y)
10mm tread when new

87598
305/30ZR20/XL 103 (Y)
9mm tread when new

After 6 months good use, over 6000 miles, my mpss still have 6-7mm all round, NO track use YET. :chuckle:
 

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+ more hassle with a puncture on the 275/305 setup. With the square setup you only need one keep one spare handy. 275/305 supply seems iffy at times. As John says, depends on your priorities....
Don't forget that the rim sizes and offset are different front to rear so one "spare" will not fit all ... unless you are just talking about the tyre itself which is not really something you can throw on quickly.
 

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My plan is to replace with MPSS and keep my Dunlops for track day as there just about legal.

Think I would prefer the 275/305 set up as when I'm on lates the roads are empty when I come home so most of the time have a little play.

What are the profiles of the 275/305 setup cheers
If you go for the square set-up in the end I wouldn't worry too much as a couple of us on the Euro Tour have it and it didn't cause either of us any issues at all over 2700+ miles of hard driving - rain & shine (including a sodden Nordschleife ...).

As John said, it's probably down to personal preference (I will probably try the staggered set-up next time and decide from there ...) but I would think that the square set-up will give slightly less understeer and slightly more oversteer than the staggered set-up and may not be quite so planted at very high speeds (though I'm happy for someone who has tried both to counter that ...) so it may depend on how you want the car to react as much as anything else.
 

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Discussion Starter #9
yes i would like to hear from someone who has tried both as anything to get rid of a bit of the understeer would be great
 

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I have found in testing that the 285/295 set up works best on the SuperSport tyre.. 275/305 just wasn't as nice balance wise plus it was slower around a lap..

On the new Cup 2 however its different again
 

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Discussion Starter #12
I have found in testing that the 285/295 set up works best on the SuperSport tyre.. 275/305 just wasn't as nice balance wise plus it was slower around a lap..

On the new Cup 2 however its different again
What was the combo and your findings
 

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Discussion Starter #17 (Edited)
I tried pretty much all other than 285/335 (due to requiring a 12J rear) but ended up going fastest and the car having the nicest balance with the 285 front and 295 K1 spec rear
What profile were these as camskill has them in stock. Is the 285/295 combo ok with the diff thingy everyone mentions
 

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Discussion Starter #19
The tyre profiles need to have the same rolling radius for back and front tyres.
Would this be ok




Michelin Tyres / Car / Michelin SuperSport Pilot Michelin Super Sport -
285/35 R20 (104Y) XL TL




Michelin Tyres / Car / Michelin SuperSport Pilot Michelin Super Sport -
295/35 R20 (105Y) XL (K1) TL

I have to admit i dont have a clue about this ive seen that k1 is a ferrari spec tyre
 

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The tyre profiles need to have the same rolling radius for back and front tyres.

In short, they don't. They need to be within a set tolerance and the 285/295 set up is within 0.5% of the stock front/rear differential which is well within tolerance.
 
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