CarSpecsHQ

295/40R21 vs 265/50R20

265/50R20 is a safe swap for 295/40R21 by the usual ±3% rule: the diameter differs by +0.47%.

21" → 20"
295/40R21 30.29" · 265/50R20 30.43" · drawn to scale

Side by side

295/40R21265/50R20Difference
Overall diameter30.29"30.43"+0.14" (+0.47%)
Section width295 mm265 mm-30 mm
Sidewall4.65"5.22"+0.57"
Rim21"20"-1"
Circumference95.2"95.6"+0.4"
Revs per mile666663-3
Ride height——+0.07"
Speedometer reads 60 mph60.060.3+0.3 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.3 mph

With 265/50R20 on a car calibrated for 295/40R21, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.5%.

Speedo showsActual speed
30 mph30.1 mph
45 mph45.2 mph
60 mph60.3 mph
70 mph70.3 mph
80 mph80.4 mph

Other sizes close to 295/40R21

Questions

Can I replace 295/40R21 with 265/50R20?

265/50R20 is a safe swap for 295/40R21 by the usual ±3% rule: the diameter differs by +0.47%.

What's the difference between 295/40R21 and 265/50R20?

265/50R20 is 0.14" taller and 30 mm narrower; the sidewall is +0.57". At an indicated 60 mph you'd actually be doing 60.3 mph.

Will 265/50R20 fit on 295/40R21 wheels?

No — 295/40R21 needs a 21" wheel and 265/50R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.