275/70R16 vs 235/85R16
235/85R16 is a safe swap for 275/70R16 by the usual ±3% rule: the diameter differs by +1.83%.
Speedometer and odometer
With 235/85R16 on a car calibrated for 275/70R16, the speedometer reads 58.9 mph when you're really doing 60, and the odometer under-counts by 1.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.5 mph |
| 45 mph | 45.8 mph |
| 60 mph | 61.1 mph |
| 70 mph | 71.3 mph |
| 80 mph | 81.5 mph |
Other sizes close to 275/70R16
Questions
Can I replace 275/70R16 with 235/85R16?
235/85R16 is a safe swap for 275/70R16 by the usual ±3% rule: the diameter differs by +1.83%.
What's the difference between 275/70R16 and 235/85R16?
235/85R16 is 0.57" taller and 40 mm narrower; the sidewall is +0.29". At an indicated 60 mph you'd actually be doing 61.1 mph.
Will 235/85R16 fit on 275/70R16 wheels?
Both use a 16" rim, so the wheel diameter matches; check the wheel's width range for a 235 mm tire and the fender clearance.