My Tire Guide

275/40R21 tire size

A 275/40R21 tire stands 29.7 inches tall and 10.8 inches wide, with a 4.3-inch sidewall on a 21-inch rim.

29.7″OVERALL 29.7 IN · RIM 21 IN10.8″4.3″WIDTH · SIDEWALL
Overall height
29.7 in753 mm
Section width
10.8 in275 mm
Sidewall height
4.3 in110 mm
Rim diameter
21 in533 mm
Circumference
93.2 in2367 mm
Revolutions per mile
680422 per km
Inch size
29.7x10.8R21

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

Sizes you can swap to

These 21-inch sizes are within two width steps and 3% of a 275/40R21's overall height, the usual limit before the speedometer, ABS and transmission notice. The closest is 265/40R21, 1.1% shorter (0.31 in). Wider sizes also need room in the wheel well and a rim width that suits them.

SizeHeightWidthAt 60 mph
265/40R21−1.1%−0.31 in−10 mm59.4 mph
285/40R21+1.1%+0.31 in+10 mm60.6 mph
255/45R21+1.3%+0.37 in−20 mm60.8 mph
295/35R21−1.8%−0.53 in+20 mm58.9 mph
295/40R21+2.1%+0.63 in+20 mm61.3 mph
255/40R21−2.1%−0.63 in−20 mm58.7 mph
265/45R21+2.5%+0.73 in−10 mm61.5 mph
285/35R21−2.7%−0.81 in+10 mm58.4 mph

Plus and minus sizes

Changing rim size means changing the sidewall to keep the same overall height. On 19-inch or 20-inch or 22-inch rims, these are the closest matches to a 275/40R21.

SizeHeightWidthAt 60 mph
245/55R19−0.2%−0.05 in−30 mm59.9 mph
245/50R20−0.1%−0.02 in−30 mm60.0 mph
245/40R22+0.2%+0.06 in−30 mm60.1 mph

Other 21-inch sizes near 275/40R21

275 mm wide, other sidewalls

40 series, other widths

See the other sizes for this rim on 21-inch tire sizes.

Shop 275/40R21 tires

These open each store's own list of 275/40R21 tires, where you can filter by type, load and speed rating.

275/40R21 questions

How tall is a 275/40R21 tire?

About 29.7 inches (753 mm) from the ground to the top of the tread, unloaded. On the vehicle, carrying weight, it sits a little lower.

What does 275/40R21 mean?

275 is the section width in millimetres (10.8 in). 40 means the sidewall is 40% of that width: 110 mm, or 4.3 in. R means radial construction, and 21 is the rim diameter in inches.

Can I use 265/40R21 instead of 275/40R21?

265/40R21 is 1.1% shorter (0.31 in) and 10 mm narrower, which is inside the usual 3% rule. With it fitted, the speedometer shows 60 mph when you are doing 59.4 mph.

What is 275/40R21 in inches?

In inch terms it is 29.7x10.8R21: 29.7 inches tall, 10.8 inches wide, for a 21-inch rim.

How many revolutions per mile does a 275/40R21 make?

About 680 turns per mile, worked out from its unloaded circumference of 93.2 inches. Makers list slightly higher numbers for their own tires, because a loaded tire rolls on a smaller radius.