295/55R20 vs 275/60R20
Going from one to the other changes the overall height by +0.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 295/55R20 | 275/60R20 | Change |
|---|---|---|---|
| Overall height | 32.8" | 33.0" | +0.7 % |
| Sidewall | 6.39" | 6.50" | +1.7 % |
| Section width | 295 mm | 275 mm | -6.8 % |
| Circumference | 103.0" | 103.6" | +0.7 % |
| Revs per mile | 615 | 611 | -0.7 % |
| Axle height | 16.39" | 16.50" | +2.8 mm |
| Approved rim width | 8.5–11" | 7.5–10" | overlap 8.5–10" |
Both are approved on a rim 8.5" to 10" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 295/55R20. Fit 275/60R20 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.2 mph | +0.2 |
| 50 mph | 50.3 mph | +0.3 |
| 70 mph | 70.5 mph | +0.5 |
| 90 mph | 90.6 mph | +0.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,066 on the road, so it under-counts by 66. At a true 70 mph the first turns 718 times a minute, the second 713.
What drivers reported
Nobody has filed a complaint naming 295/55R20. 275/60R20 carries 27.