37x12.50R17 vs 37x12.50R18
37x12.50R18 is a safe swap for 37x12.50R17 by the usual ±3% rule: the diameter differs by 0.00%.
Side by side
| 37x12.50R17 | 37x12.50R18 | Difference | |
|---|---|---|---|
| Overall diameter | 37.00" | 37.00" | 0.00" (0.00%) |
| Section width | 318 mm | 318 mm | 0 mm |
| Sidewall | 10.00" | 9.50" | -0.50" |
| Rim | 17" | 18" | +1" |
| Circumference | 116.2" | 116.2" | 0.0" |
| Revs per mile | 545 | 545 | 0 |
| Ride height | — | — | 0.00" |
| Speedometer reads 60 mph | 60.0 | 60.0 | 0.0 mph |
Speedometer and odometer
With 37x12.50R18 on a car calibrated for 37x12.50R17, the speedometer reads 60.0 mph when you're really doing 60, and the odometer over-counts by 0.0%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.0 mph |
| 45 mph | 45.0 mph |
| 60 mph | 60.0 mph |
| 70 mph | 70.0 mph |
| 80 mph | 80.0 mph |
Other sizes close to 37x12.50R17
Questions
Can I replace 37x12.50R17 with 37x12.50R18?
37x12.50R18 is a safe swap for 37x12.50R17 by the usual ±3% rule: the diameter differs by 0.00%.
What's the difference between 37x12.50R17 and 37x12.50R18?
37x12.50R18 is 0.00" taller and 0 mm wider; the sidewall is -0.50". At an indicated 60 mph you'd actually be doing 60.0 mph.
Will 37x12.50R18 fit on 37x12.50R17 wheels?
No — 37x12.50R17 needs a 17" wheel and 37x12.50R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.