CarSpecsHQ

275/40R17 vs 235/50R17

235/50R17 is a safe swap for 275/40R17 by the usual ±3% rule: the diameter differs by +2.30%.

17" rim
275/40R17 25.66" · 235/50R17 26.25" · drawn to scale

Side by side

275/40R17235/50R17Difference
Overall diameter25.66"26.25"+0.59" (+2.30%)
Section width275 mm235 mm-40 mm
Sidewall4.33"4.63"+0.30"
Rim17"17"same
Circumference80.6"82.5"+1.9"
Revs per mile786768-18
Ride height——+0.30"
Speedometer reads 60 mph60.061.4+1.4 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.4 mph

With 235/50R17 on a car calibrated for 275/40R17, the speedometer reads 58.7 mph when you're really doing 60, and the odometer under-counts by 2.3%.

Speedo showsActual speed
30 mph30.7 mph
45 mph46.0 mph
60 mph61.4 mph
70 mph71.6 mph
80 mph81.8 mph

Other sizes close to 275/40R17

Questions

Can I replace 275/40R17 with 235/50R17?

235/50R17 is a safe swap for 275/40R17 by the usual ±3% rule: the diameter differs by +2.30%.

What's the difference between 275/40R17 and 235/50R17?

235/50R17 is 0.59" taller and 40 mm narrower; the sidewall is +0.30". At an indicated 60 mph you'd actually be doing 61.4 mph.

Will 235/50R17 fit on 275/40R17 wheels?

Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 235 mm tire and the fender clearance.