CarSpecsHQ

235/55R20 vs 265/50R20

265/50R20 is a safe swap for 235/55R20 by the usual ±3% rule: the diameter differs by +0.85%.

20" rim
235/55R20 30.18" · 265/50R20 30.43" · drawn to scale

Side by side

235/55R20265/50R20Difference
Overall diameter30.18"30.43"+0.26" (+0.85%)
Section width235 mm265 mm+30 mm
Sidewall5.09"5.22"+0.13"
Rim20"20"same
Circumference94.8"95.6"+0.8"
Revs per mile668663-6
Ride height——+0.13"
Speedometer reads 60 mph60.060.5+0.5 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.5 mph

With 265/50R20 on a car calibrated for 235/55R20, the speedometer reads 59.5 mph when you're really doing 60, and the odometer under-counts by 0.8%.

Speedo showsActual speed
30 mph30.3 mph
45 mph45.4 mph
60 mph60.5 mph
70 mph70.6 mph
80 mph80.7 mph

Other sizes close to 235/55R20

Questions

Can I replace 235/55R20 with 265/50R20?

265/50R20 is a safe swap for 235/55R20 by the usual ±3% rule: the diameter differs by +0.85%.

What's the difference between 235/55R20 and 265/50R20?

265/50R20 is 0.26" taller and 30 mm wider; the sidewall is +0.13". At an indicated 60 mph you'd actually be doing 60.5 mph.

Will 265/50R20 fit on 235/55R20 wheels?

Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 265 mm tire and the fender clearance.