Different tire size?!

A_+ · May 22, 2020

I’ve been driving around with two different size rear tires and never noticed! Sure my drive suck but I figured it came with the territory (lowered) But how bad do y’all think it really affects my ride or anything for that matter?
Driver: 235/40r17
Passenger: 245/40r17

PinkieT · May 22, 2020

245/40-17 vs. 235/40-17 Differences
Diameter inches (mm)24.72 (627.8)24.4 (619.8)-0.31 (-8) -1.3%
Width inches (mm)9.65 (245)9.25 (235)-0.39 (-10) -4.1%
Circum. inches (mm)77.65 (1972.29)76.66 (1947.16)-0.99 (-25.13) -1.3%
Sidewall Height inches (mm)3.86 (98)3.7 (94)-0.16 (-4) -4.1%
Revolutions per mile (km)815.98 (507.02)826.51 (513.57)10.53 (6.54) 1.3%

They roll at slightly different speeds, so your limited slip might be wearing out faster than normal. Me, I would get a matched size pair just for that. I think the main concern is if they are the same make/model tire. The same tire in two sizes really close to each other like you have should ride and handle the same. If a different brand, or even different model of the same brand with different tread, I would think they would ride and handle differently. In that case, I would definitely get a matched pair. That's just me, though....

A_+ · May 22, 2020

Thanks for that info. Last time I buy a tire from freakin Walmart! They are the same make and model.

Adfalenski · May 23, 2020

You can have any tire size mix so long as the outside diameter is the same. Having said that, the tires should be the same configuration for both sides of the axle. My spare is the same size diameter as all of the other tires, although it is narrower(after all, it is the spare for a reason). If you have one of the donut spares that are smaller diameter, NEVER put a smaller tire on the drive axle, it will eventually tear up the differential. If you have a flat on the drive axle(rear in this case) take a tire off the non-drive axle(front in this case) and put it on the drive axle and put the undersize diameter spare on the non-drive axle.