245/60R15 vs 235/65R15
Going from one to the other changes the overall height by +1.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 245/60R15 | 235/65R15 | Change |
|---|---|---|---|
| Overall height | 26.6" | 27.0" | +1.7 % |
| Sidewall | 5.79" | 6.01" | +3.9 % |
| Section width | 245 mm | 235 mm | -4.1 % |
| Circumference | 83.5" | 84.9" | +1.7 % |
| Revs per mile | 759 | 746 | -1.7 % |
| Axle height | 13.29" | 13.51" | +5.8 mm |
| Approved rim width | 7–9" | 6.5–8.5" | overlap 7–8.5" |
Both are approved on a rim 7" to 8.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 245/60R15. Fit 235/65R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.9 mph | +0.9 |
| 70 mph | 71.2 mph | +1.2 |
| 90 mph | 91.5 mph | +1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,170 on the road, so it under-counts by 170. At a true 70 mph the first turns 885 times a minute, the second 871.
What drivers reported
245/60R15 carries 2 complaints. Nobody has filed one naming 235/65R15.