tire size question 275/40/18 or stock gt 500 size

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12-02-2012, 08:20 AM

#11

Norm Peterson

6th Gear Member

Join Date: Feb 2007

Location: state of confusion

Posts: 7,635

Quote:

Originally Posted by 157dB

275/40-18s will keep the OEM rolling diameter
unlike 285/40-18s.

235/50R18 STOCK
9.251" WIDE
27.251" TALL
85.641" ROUND
740 REVS / MILE

275/40R18
10.826" WIDE
26.661" TALL
83.759" ROUND
756 REVS / MILE

Not sure what I'm seeing there . . . and it's the 275/40 that is slightly shorter than the OE 18" tires.

235/50R18 STOCK
9.25" WIDE
27.25" TALL
767 REVS / MILE

255/45R18 STOCK
10.04" WIDE
27.05" TALL
773 REVS / MILE

275/40R18
10.83" WIDE
26.66" TALL
784 REVS / MILE

285/40R18
11.22" WIDE
26.98" TALL
775 REVS / MILE

FWIW, actual tire revs/mile are typically in the range of 3% to 3.5% greater than the calculated circumference indicates.

Norm

Last edited by Norm Peterson; 12-02-2012 at 08:38 AM.

12-10-2012, 10:08 PM

#12

Vidgomd

2nd Gear Member

Thread Starter

Join Date: Mar 2005

Location:

Posts: 293

Quote:

Originally Posted by 157dB

275/40-18s will keep the OEM rolling diameter
unlike 285/40-18s.

235/50R18 STOCK
9.251" WIDE
27.251" TALL
85.641" ROUND
740 REVS /
245/50R18
9.645" WIDE
27.645" TALL
86.851" ROUND
729 REVS / MILE

255/50R18
10.039" WIDE
28.039" TALL
88.088" ROUND
719 REVS / MILE

265/50R18
10.433" WIDE
28.433" TALL
89.325" ROUND
709 REVS / MILE

245/45R18
9.645" WIDE
26.681" TALL
83.821" ROUND
755 REVS / MILE

255/45R18
10.039" WIDE
27.035" TALL
84.934" ROUND
746 REVS / MILE

265/45R18
10.433" WIDE
27.389" TALL
86.047" ROUND
736 REVS / MILE

255/40R18
10.039" WIDE
26.031" TALL
81.780" ROUND
774 REVS / MILE

265/40R18
10.433" WIDE
26.346" TALL
82.769" ROUND
765 REVS / MILE

275/40R18
10.826" WIDE
26.661" TALL
83.759" ROUND
756 REVS / MILE

Sorry I have stock 17"
235/55/17
Thank you though

12-13-2012, 07:30 PM

#13

UPRSharad

Former Sponsor

Join Date: Jul 2011

Location: FL

Posts: 2,570

I had 275/40-18s all the way around on my '06 GT, then switched to GT500 sizes (255/45 & 285/40) and the car picked up a noticeable amount of understeer. No fun! Getting ready to put 275/40s back on it.