Tire RulerWhat changes when you switch to 245/75R17
- Height: +0.96″ (+3.2%), so ground clearance at the axle goes up 0.48″.
- Width: ±0.00″ (0 mm). A small change; clearance problems are unlikely if the height fits.
- Sidewall: +0.48″. A taller sidewall rides a bit softer and protects the wheel off-road.
- Revolutions per mile: 661 → 641. Your gears act about 3.2% taller; at 65 mph in a 0.69 top gear with 3.73s, that’s 1,843 → 1,787 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 245/75R17 than 245/70R17?
245/75R17 is 0.96 inches (3.2%) taller and 0.00 inches wider: 31.5" × 9.6" versus 30.5" × 9.6".
Will 245/75R17 change my speedometer?
Yes, by 3.2%. Going from 245/70R17 to 245/75R17, an indicated 60 mph is about 61.9 mph.
Can I replace 245/70R17 with 245/75R17?
Possibly, but the height difference is over 3%, so check clearance and plan to recalibrate the speedometer. Both fit a 17" wheel; confirm the rim width, load index and clearance for your vehicle.
Do I need to regear going from 245/70R17 to 245/75R17?
Usually not for a 3.2% change. With 3.73 gears, the 245/75R17 acts like 3.62.