37x12.50R18 vs 37x12.50R17
37x12.50R17 is a safe swap for 37x12.50R18 by the usual ±3% rule: the diameter differs by 0.00%.
Side by side
| 37x12.50R18 | 37x12.50R17 | Difference | |
|---|---|---|---|
| Overall diameter | 37.00" | 37.00" | 0.00" (0.00%) |
| Section width | 318 mm | 318 mm | 0 mm |
| Sidewall | 9.50" | 10.00" | +0.50" |
| Rim | 18" | 17" | -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 37x12.50R17 on a car calibrated for 37x12.50R18, 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 37x12.50R18
Questions
Can I replace 37x12.50R18 with 37x12.50R17?
37x12.50R17 is a safe swap for 37x12.50R18 by the usual ±3% rule: the diameter differs by 0.00%.
What's the difference between 37x12.50R18 and 37x12.50R17?
37x12.50R17 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 37x12.50R17 fit on 37x12.50R18 wheels?
No — 37x12.50R18 needs a 18" wheel and 37x12.50R17 a 17" wheel. This is a plus/minus-size swap that changes wheels too.