CarSpecsHQ

295/35R21 vs 235/50R20

235/50R20 is a safe swap for 295/35R21 by the usual ±3% rule: the diameter differs by +0.42%.

21" → 20"
295/35R21 29.13" · 235/50R20 29.25" · drawn to scale

Side by side

295/35R21235/50R20Difference
Overall diameter29.13"29.25"+0.12" (+0.42%)
Section width295 mm235 mm-60 mm
Sidewall4.06"4.63"+0.56"
Rim21"20"-1"
Circumference91.5"91.9"+0.4"
Revs per mile692689-3
Ride height——+0.06"
Speedometer reads 60 mph60.060.3+0.3 mph

Speedometer and odometer

020406080100120 reads 60 · actual 60.3 mph

With 235/50R20 on a car calibrated for 295/35R21, the speedometer reads 59.7 mph when you're really doing 60, and the odometer under-counts by 0.4%.

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

Other sizes close to 295/35R21

Questions

Can I replace 295/35R21 with 235/50R20?

235/50R20 is a safe swap for 295/35R21 by the usual ±3% rule: the diameter differs by +0.42%.

What's the difference between 295/35R21 and 235/50R20?

235/50R20 is 0.12" taller and 60 mm narrower; the sidewall is +0.56". At an indicated 60 mph you'd actually be doing 60.3 mph.

Will 235/50R20 fit on 295/35R21 wheels?

No — 295/35R21 needs a 21" wheel and 235/50R20 a 20" wheel. This is a plus/minus-size swap that changes wheels too.