255/35R18 vs 245/40R18

255/35R18 vs 245/40R18: Comparision Size Chart


255/35R18 (Tire 1)245/40R18 (Tire 2)Difference
Tire Size In Inches25X10R1825.7X9.6R18
Diameter25.03"635.7 mm25.72"653.2 mm2.75%
Tread Width10255 mm9.6"245 mm-3.92%
Rim Diameter18"457.2 mm18"457.2 mm0%
Sidewall Height3.51"89.25 mm3.86"98 mm9.8%
Circumference78.63"1997.11 mm80.8"1997.11 mm2.75%
Revs/Mile805.8 Revs/Mile784.16 Revs/Mile-21.64
Revs/Kilometer500.7 Revs/Mile487.26 Revs/Mile-13.44
Tire 1 Front View
10"
25.03"
Tire 2 Front View
10"
25.72"
Tire 1 Side View
Tire 1 Wheel
Circumference 1
78.63"
18"
3.51"
805.8 Revs/Mile
Tire 2 Side View
Tire 2 Wheel
Circumference 2
80.8"
18"
3.86"
784.16 Revs/Mile

Speedometer Error

255/35R18 (Mph)245/40R18 (Mph)
2020.55
3535.96
5051.38
6566.79
8082.2
9092.48
100102.75

245/40R18 vs 255/35R18: Gas Mileage & Performance Comparison

* Below is a comparison table. Assuming 2 tires of the same manufacturer, material and tested on the same road conditions.

255/35R18245/40R18
Wet/Snowy RoadsBetter TractionReduced Traction
Rough TerrainReduced StabilitySmoother Ride
Handling/SteeringBetterLess Responsive
Gas MileageGoodBetter
Road NoiseQuietQuieter
CostLess ExpensiveMore Expensive

Can You Replace The 255/35R18 With The 245/40R18?

Yes, both tires have the same rim diameter, and the 245/40R18 has a bigger overall diameter than the 255/35R18 which is only 2.68% (0.69-inch), it is the allowable margin (±3%).

When you want to replace a different tire size, as a rule, for the rim diameter, you will need to be sure that your tires and rims are an exact match, e.g. a 255/35R18 tire will only fit on a 18″ diameter rim.

You Can check our tools and charts below to find your size:

*Disclaimer: The information provided on the tire size is for general informational purposes only. We recommend that you consult a certified tire specialist or National Highway Traffic Safety Administration (NHTSA) sets specific guidelines for tires used on vehicles.


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Jamie Hicks

Sullivan Kane

Tire Technician at TireSizesCalculator

Sullivan is a Tire Technician specializing in tire repair at TireSizesCalculator. With over 6 years of experience in the industry, Sullivan has become an expert in tire repair, maintenance & installation.


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