185/55R16 vs 215/40R17
215/40R17 is 0.24 in (6.1 mm) shorter than 185/55R16, a −1.00% diameter difference. With the speedometer set for 185/55R16, an indicated 60 mph is 59.4 mph on 215/40R17.
Is this a safe swap?
Diameter difference −1.00%: within the ±3% guideline
By overall diameter alone, 215/40R17 falls inside the ±3% range commonly used as a guideline when replacing 185/55R16. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.
| Measurement | 185/55R16 | 215/40R17 | Difference | % diff |
|---|---|---|---|---|
| Overall diameter | 24.01 in (609.9 mm) | 23.77 in (603.8 mm) | −0.24 in (−6.1 mm) | −1.00% |
| Sidewall height | 4.01 in (101.8 mm) | 3.39 in (86.0 mm) | −0.62 in (−15.7 mm) | −15.48% |
| Section width | 7.28 in (185.0 mm) | 8.46 in (215.0 mm) | +1.18 in (+30.0 mm) | +16.22% |
| Circumference | 75.44 in (1,916.1 mm) | 74.68 in (1,896.9 mm) | −0.75 in (−19.2 mm) | −1.00% |
| Revolutions per mile | 840 | 848 | +8 | +1.01% |
| Indicated | Actual on 185/55R16 | Actual on 215/40R17 | Difference |
|---|---|---|---|
| 30 mph | 30.0 mph | 29.7 mph | −0.3 mph |
| 60 mph | 60.0 mph | 59.4 mph | −0.6 mph |
| 75 mph | 75.0 mph | 74.2 mph | −0.8 mph |
Ride-height change: 215/40R17 lowers the vehicle by 0.12 in (3.1 mm) at the axle (half the −6.1 mm diameter difference).
215/40R17 is 0.24 in shorter than 185/55R16 and 30 mm wider, a 1.00% difference in overall diameter.
With the speedometer calibrated for 185/55R16, an indicated 60 mph is actually 59.4 mph on 215/40R17, and revolutions per mile change from 840 to 848.
215/40R17 mounts on a 17-inch wheel, a plus-1 fitment from the 16-inch wheel of 185/55R16.
Size pages
Other comparisons with 185/55R16
- 155/80R14 vs 185/55R16
- 195/65R14 vs 185/55R16
- 185/70R14 vs 185/55R16
- 185/60R15 vs 185/55R16
- 225/50R15 vs 185/55R16
- 205/55R15 vs 185/55R16
- 175/65R15 vs 185/55R16
- 195/60R15 vs 185/55R16
Other comparisons with 215/40R17
- 165/65R15 vs 215/40R17
- 215/50R15 vs 215/40R17
- 185/60R15 vs 215/40R17
- 225/50R15 vs 215/40R17
- 205/55R15 vs 215/40R17
- 175/65R15 vs 215/40R17
- 215/45R16 vs 215/40R17
- 195/50R16 vs 215/40R17
Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.