245/45R18

About 245/45R18

Factory fitments for 245/45R18 include the BMW 5 Series, Mercedes-Benz E-Class, Nissan Maxima — meaning replacement tires in this size see steady demand and broad brand availability. At 26.68″ overall diameter, 245/45R18 turns 756 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 45% aspect ratio gives it a low-profile sidewall that delivers sharp steering response but transmits road imperfections. The 18″ rim pairing is typical for full-size truck, premium SUV, and sport-sedan platforms, so compatible wheels are easy to source new or used. Going one step shorter to 235/45R18 drops diameter by 1.33%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 225/50R18 adds 0.66% diameter — also inside the safe window, with marginally taller ride height. If you are shopping for a direct replacement, any tire within roughly ±0.7″ of the 26.68″ stock diameter (about ±2% in percentage terms) will keep ABS, TPMS, and odometer readings inside the vehicle's designed tolerance.

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