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255/70R18

255/70R18 ships as an OEM size on the Jeep Gladiator, Jeep Wrangler. At 32.06″ diameter with a 7.03″ sidewall (70% of section width), this size turns 629 revolutions per mile.

Overall diameter
32.06″
814.2 mm
Section width
10.04″
255 mm
Sidewall
7.03″
178.5 mm
Circumference
100.7″
Revs / mile
629
Rim
18″

About 255/70R18

Factory fitments for 255/70R18 include the Jeep Gladiator, Jeep Wrangler — meaning replacement tires in this size see steady demand and broad brand availability. At 32.06″ overall diameter, 255/70R18 turns 629 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 70% aspect ratio gives it a tall, compliant sidewall that absorbs bumps well and protects rims off-road. 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 265/65R18 drops diameter by 1.54%, which stays within the ±3% fitment safe zone for most vehicles. Stepping up to 275/65R18 adds 0.06% 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 32.06″ stock diameter (about ±2% in percentage terms) will keep ABS, TPMS, and odometer readings inside the vehicle's designed tolerance.

Compare with another size

Type to search · try 275/65R18 or "33" for inch aliases
Common upsizes from 255/70R18:
Don't know your stock size? Load it by vehicle:

255/70R18

Diameter
32.06″ / 814.2mm
Section Width
10.04
Sidewall
7.03″ / 178.5mm
Circumference
100.7
Revs/Mile
629
See tires in 255/70R18

245/65R18

Diameter
30.54″ / 775.7mm
Section Width
9.65
Sidewall
6.27″ / 159.25mm
Circumference
95.94
Revs/Mile
660
See tires in 245/65R18
255/70R18 · 32.06245/65R18 · 30.54

Speedometer & Diameter Impact

Diameter Change
-4.73%
Sidewall Change
-0.76″
Revs/Mile Δ
31
mph

At an indicated 60 mph, your actual speed is 57.16 mph (91.99 km/h). Your speedometer reads 4.73% high versus actual speed.

Vehicles that fit 255/70R18

Similar sizes on the same rim

Speedometer impact if you upsize from 255/70R18