CarSpecsHQ

265/45R21 vs 295/45R20

295/45R20 is a safe swap for 265/45R21 by the usual ±3% rule: the diameter differs by +0.21%.

21" → 20"
265/45R21 30.39" · 295/45R20 30.45" · drawn to scale

Side by side

265/45R21295/45R20Difference
Overall diameter30.39"30.45"+0.06" (+0.21%)
Section width265 mm295 mm+30 mm
Sidewall4.69"5.23"+0.53"
Rim21"20"-1"
Circumference95.5"95.7"+0.2"
Revs per mile664662-1
Ride height——+0.03"
Speedometer reads 60 mph60.060.1+0.1 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.1 mph

With 295/45R20 on a car calibrated for 265/45R21, the speedometer reads 59.9 mph when you're really doing 60, and the odometer under-counts by 0.2%.

Speedo showsActual speed
30 mph30.1 mph
45 mph45.1 mph
60 mph60.1 mph
70 mph70.1 mph
80 mph80.2 mph

Other sizes close to 265/45R21

Questions

Can I replace 265/45R21 with 295/45R20?

295/45R20 is a safe swap for 265/45R21 by the usual ±3% rule: the diameter differs by +0.21%.

What's the difference between 265/45R21 and 295/45R20?

295/45R20 is 0.06" taller and 30 mm wider; the sidewall is +0.53". At an indicated 60 mph you'd actually be doing 60.1 mph.

Will 295/45R20 fit on 265/45R21 wheels?

No — 265/45R21 needs a 21" wheel and 295/45R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.