255/30R22 vs 265/35R21

Q: Can I replace 255/30R22 with 265/35R21?

265/35R21 is a safe swap for 255/30R22 by the usual ±3% rule: the diameter differs by +1.00%.

265/35R21 is a safe swap for 255/30R22 by the usual ±3% rule: the diameter differs by +1.00%.

255/30R22 28.02" · 265/35R21 28.30" · drawn to scale

Side by side

	255/30R22	265/35R21	Difference
Overall diameter	28.02"	28.30"	+0.28" (+1.00%)
Section width	255 mm	265 mm	+10 mm
Sidewall	3.01"	3.65"	+0.64"
Rim	22"	21"	-1"
Circumference	88.0"	88.9"	+0.9"
Revs per mile	720	713	-7
Ride height	—	—	+0.14"
Speedometer reads 60 mph	60.0	60.6	+0.6 mph

Speedometer and odometer

With 265/35R21 on a car calibrated for 255/30R22, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.0%.

Speedo shows	Actual speed
30 mph	30.3 mph
45 mph	45.4 mph
60 mph	60.6 mph
70 mph	70.7 mph
80 mph	80.8 mph

Other sizes close to 255/30R22

Questions

Can I replace 255/30R22 with 265/35R21?

265/35R21 is a safe swap for 255/30R22 by the usual ±3% rule: the diameter differs by +1.00%.

What's the difference between 255/30R22 and 265/35R21?

265/35R21 is 0.28" taller and 10 mm wider; the sidewall is +0.64". At an indicated 60 mph you'd actually be doing 60.6 mph.

Will 265/35R21 fit on 255/30R22 wheels?

No — 255/30R22 needs a 22" wheel and 265/35R21 a 21" wheel. This is a plus/minus-size swap that changes wheels too.