New summer tires

[Boxstard]

Time to get a set of new summer tires.

Running 205/50 front and 255/40 rear on 17” wheels now. I want Michelin Pilot Sport 4S but no matching sizes available.

I’m wondering if 215/45 and 245/40 tires work as good, since diameter difference is only 1%? I think 255 is a bit overkill for my 2.5 anyway, so won’t mind going a bit narrower for rears, while a bit wider fronts reduce built-in understeer altogether. And a bit smaller diameter and 1 pound lighter weight probably help acceleration, if anything.

Anybody running the combo?

[BrantyB]

FWIW I use 225/45 and 255/40. That matches the rolling diameter well.

[Boxstard]

Originally Posted by BrantyB

FWIW I use 225/45 and 255/40. That matches the rolling diameter well.

I was going to do that but Michelin PS4S does not come in 255/40 size… so I went for 215/45 and 245/40 that too closely match in terms of diameter/ circumference.

Got new tires on today, it was wet too so took it easy but like sharp steering feel and overall nice ride. Hope I can test on dry road tomorrow.

Compared with old 255/40 AS3+ replaced, my rear wheel with new 245/40 PS4S is 2lbs lighter, while my front wheel saved 3lbs going from 205/50 AS3 to 215/45 PS4S. 10lbs net loss on rotational mass equals about 70lbs static weight saving, not bad to help my 2.5 get up and go quicker