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285/70R17 vs 255/85R17

255/85R17 is 1.7″ taller than 285/70R17 on average, going by the heights their makers list (32.9″ vs 34.6″). On paper the gap is 1.36″.

285/70R17 and 255/85R17 drawn to the same scale: 32.9 and 34.6 inches tall on average as listed285/70R1732.9″255/85R1734.6″+1.7″
Drawn to the same scale, using the average height the makers list for each size.

What changes

Going from 285/70R17 to 255/85R17.

Lift+0.87″
Width−1.18″
Speedometer5.3% slow

Lift is half the height difference, since the axle sits at the middle of the tire. The speedometer figure assumes it was set for 285/70R17: at an indicated 60 mph you'd be doing 63.2 mph.

Side by side

285/70R17255/85R17Difference
Listed height ″32.70–33.1534.60+1.74
Size code height ″32.7134.07+1.36
Width ″11.2210.04−1.18
Listed width ″11.4–11.610.1−1.4
Sidewall ″7.858.53+0.68
Wheel ″1717same
Weight lb46.0–65.764.0+7.3
Tread depth /32″13–1919+1.9
Tires listed361

All 33-inch tire sizes · All 35-inch tire sizes

Tires sold in both sizes

The same model in each size, by the heights the maker lists. Averages where a model comes in several load ranges.

Tire285/70R17 ″255/85R17 ″Taller byHeavier by
Mickey Thompson Baja Boss A/T32.9034.60+1.70″+8.5 lb

Questions about 285/70R17 vs 255/85R17

How much taller is 255/85R17 than 285/70R17?

1.74″ on average, going by the heights tire makers list: 285/70R17 tires are listed at 32.70–33.15″ and 255/85R17 at 34.60″. The size codes work out to 32.71″ and 34.07″, a 1.36″ difference.

How much lift does 255/85R17 give over 285/70R17?

The tire's radius grows by 0.87″, so the axle sits about 0.87″ higher, and the top of the tread comes 0.87″ closer to the fender. 255/85R17 is also 1.18″ narrower on paper, 0.59″ per side on the same wheel. Whether it fits depends on your vehicle, lift and wheel offset.

Will my speedometer be off with 255/85R17 instead of 285/70R17?

Yes. If it's set for 285/70R17, it will read about 5.3% slow: at an indicated 60 mph you'll be doing 63.2 mph.

Can 255/85R17 go on the same wheel as 285/70R17?

Both fit a 17-inch wheel. Wheel widths approved for both run from 7.5″ to 8.0″.