235/40/zr18 on a 18/7.5 wheel with a eibach prokit drop? Also w/o the drop the tire sticks out alil already. And how will my speedo be affected?
Thanks
Jon

 

Not 100% sure... 235 may be cutting it close. I currently run 225/40/18 and I'm fine. Previously I ran 225/45/18 that that was OK too.. but pretty close. 235 may be too close. FYI, I have H&R Sports (1.75" drop f/r).

As for the speedo... check out this site.... http://www.miata.net/garage/tirecalc.html . Put in your stock size.. then your new size and it will tell you how off you will be.

 

Your speedo and odo will be off a little. It all depends on the offset though.

 

45 offset, I guess no ones riding in the back of my car from now on.

 

Actually, 235/40/18 is closer to stock diameter then 225/40/18.
I’m currently running 225/40 and I’m switching to 235/40 when I buy new rubber next month.

Shawn S

 

I dont know about an Eibach drop, but I run 235\40\18's on an 18x7.5 with CT springs and zero rub.

and Bigman, like shawn said, 235\40\18 is almost dead on to stock rolling diameter. At 70 MPH, I would read 69.9. Stock is 25.5in tall and 235\40\18 is 25.4 something. This is one of the reasons I went with 235, not to mention I like the look of the wider tire.

 

Offset is what counts. You should be ok with a +45 & 235-40-18's.

 

I have a pair of Nitto 555 235/40/18's for sale in the blackmarket

 

with your drop id say that you may rub in the rear now and then, but nothing major.