Is 245/40/18 okay for the front 18x8.5 wheels? (225/40 current)

My current 225/40 is a bit stretched, I'd like to run a little wider and have a flat side wall instead of stretch.

 

245/40/18 mounted on an 18x8.5 is within specs with an ET50-55. However, I would personally go with an 245/35/18; ET50-55 which is closer to stock. Good luck.

 

Thanks a lot. Yeah I'm debating on the aspect ratio between 35 and 40 series.

 

225/40x18 height is 637.2mm
245/40x18 height is 653.2mm, which is 15mm higher (close to 3/4"), so I would say much too tall.
245/35x18 height is 628.7, which is pretty close to stock height.

 

35 is a bit to low for me for the front. I'm gonna run 295/30 or 305/30 on the rear.

 

I run 245/35-18 x 8.5 on a 40mm offset for my 996. However, I do have the camber set for the track so I have no clearance problems with the aggressive offset. This also matches the stock diameter 225/40 for the front. I would not run 245/40 for reasons stated earlier. much too tall for me. I do agree that 225 on 8.5 doesn't look too good...I had those for awhile and it ooked funky.

 

It appears the general consensus is 245/35/18. If you plan on running 30 on the rear against a 40 on the front, my past experience tells me it will appear aesthetically awkward . It will appear as though the rear tires are on the front, and the front tires on the rear. As long as I am speaking aesthetics, your best combo would be 245/35/18 F + 295/30/18 R. And, that is my final answer.

 

On the rear I run 285/30-18 since I have 10" wheels with a 47mm offset. On 10" 285 seems to be the right size. I think I would go with 295 or 305 only on 11 inch and I am not sure what offset would be good in that case.