235/65R18

About 235/65R18

Factory fitments for 235/65R18 include the Buick Enclave, Cadillac XT5, Chevrolet Blazer — meaning replacement tires in this size see steady demand and broad brand availability. At 30.03″ overall diameter, 235/65R18 turns 672 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 65% aspect ratio gives it a balanced sidewall — enough compliance for daily comfort without vague steering. 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 245/60R18 drops diameter by 1.51%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 255/60R18 adds 0.07% 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 30.03″ stock diameter (about ±2% in percentage terms) will keep ABS, TPMS, and odometer readings inside the vehicle's designed tolerance.

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