Tire RulerWhat changes when you switch to 325/65R18
- Height: +0.37″ (+1.1%), so ground clearance at the axle goes up 0.19″.
- Width: +1.18″ (30 mm). Check inner clearance to the suspension and frame, and the fender liner at full lock.
- Sidewall: +0.19″. A taller sidewall rides a bit softer and protects the wheel off-road.
- Revolutions per mile: 589 → 582. Your gears act about 1.1% taller; at 65 mph in a 0.69 top gear with 3.73s, that’s 1,641 → 1,624 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 325/65R18 than 295/70R18?
325/65R18 is 0.37 inches (1.1%) taller and 1.18 inches wider: 34.6" × 12.8" versus 34.3" × 11.6".
Will 325/65R18 change my speedometer?
Yes, by 1.1%. Going from 295/70R18 to 325/65R18, an indicated 60 mph is about 60.7 mph.
Can I replace 295/70R18 with 325/65R18?
Often, yes: the height difference is within the ±3% most tire shops accept. Both fit an 18" wheel; confirm the rim width, load index and clearance for your vehicle.
Do I need to regear going from 295/70R18 to 325/65R18?
Usually not for a 1.1% change. With 3.73 gears, the 325/65R18 acts like 3.69.