235/70R16 vs 225/65R16
New overall diameter
27.52″
was 28.95″
True speed at an indicated 60
57.0 mph
your speedo reads high
Revolutions per mile
733
was 697, +36
| Measurement | 235/70R16 | 225/65R16 | Change |
|---|---|---|---|
| Overall diameter | 28.95″ | 27.52″ | −1.44″ (−5.0%) |
| Sidewall height | 6.48″ (164.5 mm) | 5.76″ (146.3 mm) | −18.3 mm |
| Tread width | 235 mm | 225 mm | −10 mm |
| Circumference | 90.96″ | 86.44″ | −4.51″ |
| Revs per mile | 697 | 733 | +36 |
| Speedometer error | baseline | −5.0% | reads high |
Diameter overlay
235/70R16 225/65R16
Speedometer check
With 225/65R16 fitted, when the speedometer shows the indicated speed, your actual speed is:
25 mph shown
23.8 mph actual
35 mph shown
33.3 mph actual
45 mph shown
42.8 mph actual
55 mph shown
52.3 mph actual
65 mph shown
61.8 mph actual
75 mph shown
71.3 mph actual
Common questions
- Will 225/65R16 fit instead of 235/70R16?
- Overall diameter changes 5.0%; section width changes -10 mm. Diameter comparison alone cannot confirm fitment. Verify the vehicle maker's approved rim width, tire load and speed ratings, and clearance at full steering lock and suspension compression. Confirm any possible ABS, traction-control, speedometer, and drivetrain effects with the vehicle maker or a qualified tire professional. Overall diameter goes from 28.95″ to 27.52″, a change of −5.0%. The rule of thumb most shops use: under 3% is fine, 3 to 5% needs a clearance check, over 5% needs recalibration.
- How far off will my speedometer read on 225/65R16?
- At an indicated 60 mph you are really doing about 57.0 mph, a −5.0% error. The speedometer reads high, so you are going slower than it shows.
- What is the difference in revolutions per mile between 235/70R16 and 225/65R16?
- 235/70R16 turns about 697 times per mile and 225/65R16 turns about 733, a difference of +36. Your speedometer and odometer both count rotations, so this number is what throws them off.