275/35R18 vs 315/35R17
315/35R17 is a safe swap for 275/35R18 by the usual ±3% rule: the diameter differs by +0.40%.
Speedometer and odometer
With 315/35R17 on a car calibrated for 275/35R18, the speedometer reads 59.8 mph when you're really doing 60, and the odometer under-counts by 0.4%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.1 mph |
| 45 mph | 45.2 mph |
| 60 mph | 60.2 mph |
| 70 mph | 70.3 mph |
| 80 mph | 80.3 mph |
Other sizes close to 275/35R18
- 275/35R18 vs 245/40R18+0.54%
- 275/35R18 vs 225/45R18+1.54%
- 275/35R18 vs 225/40R18-1.92%
- 275/35R18 vs 245/45R18+4.31%
- 275/35R18 vs 235/45R18+2.92%
- 275/35R18 vs 235/40R18-0.69%
- 275/35R18 vs 215/50R17-0.45%
- 275/35R18 vs 235/45R17-0.99%
- 275/35R18 vs 245/45R17+0.40%
- 275/35R18 vs 255/35R18-2.15%
- 275/35R18 vs 255/40R18+1.77%
- 275/35R18 vs 245/35R19+0.68%
Questions
Can I replace 275/35R18 with 315/35R17?
315/35R17 is a safe swap for 275/35R18 by the usual ±3% rule: the diameter differs by +0.40%.
What's the difference between 275/35R18 and 315/35R17?
315/35R17 is 0.10" taller and 40 mm wider; the sidewall is +0.55". At an indicated 60 mph you'd actually be doing 60.2 mph.
Will 315/35R17 fit on 275/35R18 wheels?
No — 275/35R18 needs a 18" wheel and 315/35R17 a 17" wheel. This is a plus/minus-size swap that changes wheels too.