215/50R17 vs 225/55R17
New overall diameter
26.74″
was 25.46″
True speed at an indicated 60
63.0 mph
your speedo reads low
Revolutions per mile
754
was 792, −38
| Measurement | 215/50R17 | 225/55R17 | Change |
|---|---|---|---|
| Overall diameter | 25.46″ | 26.74″ | +1.28″ (+5.0%) |
| Sidewall height | 4.23″ (107.5 mm) | 4.87″ (123.8 mm) | +16.3 mm |
| Tread width | 215 mm | 225 mm | +10 mm |
| Circumference | 80.00″ | 84.02″ | +4.02″ |
| Revs per mile | 792 | 754 | −38 |
| Speedometer error | baseline | +5.0% | reads low |
Diameter overlay
215/50R17 225/55R17
Speedometer check
With 225/55R17 fitted, when the speedometer shows the indicated speed, your actual speed is:
25 mph shown
26.3 mph actual
35 mph shown
36.8 mph actual
45 mph shown
47.3 mph actual
55 mph shown
57.8 mph actual
65 mph shown
68.3 mph actual
75 mph shown
78.8 mph actual
Common questions
- Will 225/55R17 fit instead of 215/50R17?
- 5.0% is past the 5% mark, which is where this stops being a tire choice and starts being a project. Expect rubbing, meaningful speedometer error, and extra load on ABS, stability control and the drivetrain. Recalibration is the usual fix. Your speedometer will read low, so you are going faster than it says. Overall diameter goes from 25.46″ to 26.74″, 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 225/55R17?
- At an indicated 60 mph you are really doing about 63.0 mph, a +5.0% error. The speedometer reads low, so you are going faster than it shows.
- What is the difference in revolutions per mile between 215/50R17 and 225/55R17?
- 215/50R17 turns about 792 times per mile and 225/55R17 turns about 754, a difference of −38. Your speedometer and odometer both count rotations, so this number is what throws them off.