: Will 255/40/18's work in the rear



Josh D. Nooney
09-18-11, 10:42 PM
I can pick up a set of 255/40/18's really cheap for the rear of my car. I know they aren't the correct size but has anyone used this size sucessfully? Is the ABS or stability control system going to go haywire? The tires are 1" shorter than 255/45/18's

valjan1
09-19-11, 06:17 PM
I owne a 05 sts4 v8 and i put 4 bridgstone RE 760 SPORT ( by the way i hate them in the rain but good on dry) 255/45 18 W and it fits right on now since i worn them out in two summers i plan to put 4 Falken 255/40ZR18 300-AA-A 99Y p/n 28195890 porches won at lagunaseca on wet (floded) pavement and dry pavement with falken tires in front of corvette and bm and everyother i was stunt.Since i live in the north it raines often in fall so i need a tyre that i can count on.

valjan1
09-19-11, 06:25 PM
i run on 17 inches during winter i have michelin ice 235/55/17 and i does not affect nothing all systems are green .No bugs whatsoever

valjan1
09-19-11, 06:31 PM
The difference is only half an inche since you calculate from the center half of the tyre

caddyfat2
09-21-11, 12:41 PM
I can pick up a set of 255/40/18's really cheap for the rear of my car. I know they aren't the correct size but has anyone used this size sucessfully? Is the ABS or stability control system going to go haywire? The tires are 1" shorter than 255/45/18's

They are not shorter but the 255/40/18 is a tad wider. 40 vs 45.

EChas3
09-21-11, 08:17 PM
All else equal, a 40-series tire should be a bit smaller or shorter than a 45-series tire. The number indicates a percentage of tire height to width and the sidewall varies, not the width. A 255/40R18 sidewall height is 102mm; 255/45R18 is 114.75mm. 12.75mm ~ half an inch.

It's a bit more complicated when comparing different width tires on the same rims. 255's will crown more than 235's or 255/45~114.75 vs. 235/50-117.5, but the 255's are a little taller due to the crown affect. Is it a tenth of an inch?

Some members have reported issues with AWD & Stability Control with mis-matched tires. You may be fine but...