CarSpecsHQ

205/40R17 vs 235/40R17

235/40R17 is outside the ±3% rule as a replacement for 205/40R17: the diameter differs by +4.03%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

17" rim
205/40R17 23.46" · 235/40R17 24.40" · drawn to scale

Side by side

205/40R17235/40R17Difference
Overall diameter23.46"24.40"+0.94" (+4.03%)
Section width205 mm235 mm+30 mm
Sidewall3.23"3.70"+0.47"
Rim17"17"same
Circumference73.7"76.7"+3.0"
Revs per mile860827-33
Ride height——+0.47"
Speedometer reads 60 mph60.062.4+2.4 mph

Speedometer and odometer

020406080100120 reads 60 · actual 62.4 mph

With 235/40R17 on a car calibrated for 205/40R17, the speedometer reads 57.7 mph when you're really doing 60, and the odometer under-counts by 4.0%.

Speedo showsActual speed
30 mph31.2 mph
45 mph46.8 mph
60 mph62.4 mph
70 mph72.8 mph
80 mph83.2 mph

Other sizes close to 205/40R17

Questions

Can I replace 205/40R17 with 235/40R17?

235/40R17 is outside the ±3% rule as a replacement for 205/40R17: the diameter differs by +4.03%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 205/40R17 and 235/40R17?

235/40R17 is 0.94" taller and 30 mm wider; the sidewall is +0.47". At an indicated 60 mph you'd actually be doing 62.4 mph.

Will 235/40R17 fit on 205/40R17 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.