My Tire Guide

235/45R18 tire size

A 235/45R18 tire stands 26.3 inches tall and 9.3 inches wide, with a 4.2-inch sidewall on an 18-inch rim.

26.3″OVERALL 26.3 IN · RIM 18 IN9.3″4.2″WIDTH · SIDEWALL
Overall height
26.3 in669 mm
Section width
9.3 in235 mm
Sidewall height
4.2 in106 mm
Rim diameter
18 in457 mm
Circumference
82.7 in2101 mm
Revolutions per mile
766476 per km
Inch size
26.3x9.3R18

Compare it with any other size in the tire size calculator.

Sizes you can swap to

These 18-inch sizes are within two width steps and 3% of a 235/45R18's overall height, the usual limit before the speedometer, ABS and transmission notice. The closest is 215/50R18, 0.5% taller (0.14 in). Wider sizes also need room in the wheel well and a rim width that suits them.

SizeHeightWidthAt 60 mph
215/50R18+0.5%+0.14 in−20 mm60.3 mph
255/40R18−1.1%−0.30 in+20 mm59.3 mph
225/45R18−1.3%−0.35 in−10 mm59.2 mph
245/45R18+1.3%+0.35 in+10 mm60.8 mph
225/50R18+2.0%+0.53 in−10 mm61.2 mph
245/40R18−2.3%−0.61 in+10 mm58.6 mph
215/45R18−2.7%−0.71 in−20 mm58.4 mph
255/45R18+2.7%+0.71 in+20 mm61.6 mph

Plus and minus sizes

Changing rim size means changing the sidewall to keep the same overall height. On 16-inch or 17-inch or 19-inch or 20-inch rims, these are the closest matches to a 235/45R18.

SizeHeightWidthAt 60 mph
265/50R16+0.4%+0.11 in+30 mm60.2 mph
215/55R17−0.1%−0.02 in−20 mm60.0 mph
265/35R19−0.1%−0.02 in+30 mm59.9 mph
225/35R20−0.5%−0.13 in−10 mm59.7 mph

Other 18-inch sizes near 235/45R18

235 mm wide, other sidewalls

45 series, other widths

See the other sizes for this rim on 18-inch tire sizes.

Shop 235/45R18 tires

These open each store's own list of 235/45R18 tires, where you can filter by type, load and speed rating.

235/45R18 questions

How tall is a 235/45R18 tire?

About 26.3 inches (669 mm) from the ground to the top of the tread, unloaded. On the vehicle, carrying weight, it sits a little lower.

What does 235/45R18 mean?

235 is the section width in millimetres (9.3 in). 45 means the sidewall is 45% of that width: 106 mm, or 4.2 in. R means radial construction, and 18 is the rim diameter in inches.

Can I use 215/50R18 instead of 235/45R18?

215/50R18 is 0.5% taller (0.14 in) and 20 mm narrower, which is inside the usual 3% rule. With it fitted, the speedometer shows 60 mph when you are doing 60.3 mph.

What is 235/45R18 in inches?

In inch terms it is 26.3x9.3R18: 26.3 inches tall, 9.3 inches wide, for an 18-inch rim.

How many revolutions per mile does a 235/45R18 make?

About 766 turns per mile, worked out from its unloaded circumference of 82.7 inches. Makers list slightly higher numbers for their own tires, because a loaded tire rolls on a smaller radius.