Tire RulerWhat changes when you switch to 275/70R17
- Height: +0.10″ (+0.3%), so ground clearance stays practically the same.
- Width: +0.79″ (20 mm). Check inner clearance to the suspension and frame, and the fender liner at full lock.
- Sidewall: +0.05″. A taller sidewall rides a bit softer and protects the wheel off-road.
- Revolutions per mile: 629 → 627. Your gears act about 0.3% taller; at 65 mph in a 0.69 top gear with 3.73s, that’s 1,754 → 1,749 RPM.
Sizes are theoretical, from the sidewall code. The same size can differ by a few tenths of an inch between brands and tread patterns; check the maker’s spec sheet for the exact model.
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Frequently asked questions
How much bigger is 275/70R17 than 255/75R17?
275/70R17 is 0.10 inches (0.3%) taller and 0.79 inches wider: 32.2" × 10.8" versus 32.1" × 10.0".
Will 275/70R17 change my speedometer?
Yes, by 0.3%. Going from 255/75R17 to 275/70R17, an indicated 60 mph is about 60.2 mph.
Can I replace 255/75R17 with 275/70R17?
Often, yes: the height difference is within the ±3% most tire shops accept. Both fit a 17" wheel; confirm the rim width, load index and clearance for your vehicle.
Do I need to regear going from 255/75R17 to 275/70R17?
Usually not for a 0.3% change. With 3.73 gears, the 275/70R17 acts like 3.72.