I am wonder if the larger overall diameter of the 255/45ZR17 (25.9") offsets the benefits of the wider tread compared to the 245/40ZR17 with diameter 24.5". The latter tire more closely approximates the front available chosen tire of 225/45ZR17 with 24.6" diameter.

Would be nice to have more stagger, but the larger diameter concerns me.

Thanks.

 

don't do it.
with a much larger rear tire diam., ABS might not work! u can change dia. of tires but u need to be same front to rear for the abs, it may fail or prematurely engage 'cause it sees the wheels rotating at different speeds earlier on when slowing.

also, that much larger diam will reduce effective final drive....result in worse acceleration and speedo reading low......SPEEDING TICKET!

and, outside diam plays a huge but overlooked role in fender clearance, those may rub
fender bigtime, whereas same width tire in 24.8in dia has no problemas clearing.

u can try 5mm spacer on rear only, that will result in more grip and look "fatter", effectively getting what u may desire. the car will push slightly more, similar but unknown amount to putting the wider tire.

 

Since these are track tires the speedo issue doesn't count, and the ABS issue probably does not either.

Clearance could be an issue, but it would seem that the higher effective gear ratio might be a larger concern. The 255 is 3% taller than the 245 and 2% taller than the stock tire.. taller meaning larger in circumference.

With all the revisions you have made to the suspension I would not be terribly concerned with staying exactly on the stock stagger. If it was my choice I think I would stay with the 245 given the trade offs on this one.

 

Thanks for the replies. I was thinking, while this post was cooking, that the 245 offers less weight, lower effective gear ratio, as Cdelena mentioned, and way more grip than what my abilities might be able to explore at this time; I wasn't sure if 255 will give better lateral grip. So I was pretty much settling on a 245.