tireheight.com

305/70R17 vs 285/75R17

305/70R17 and 285/75R17 are about the same height: 33.9″ and 33.9″ on average as listed by their makers (33.81″ and 33.83″ on paper).

305/70R17 and 285/75R17 drawn to the same scale: 33.9 and 33.9 inches tall on average as listed305/70R1733.9″285/75R1733.9″
Drawn to the same scale, using the average height the makers list for each size.

What changes

Going from 305/70R17 to 285/75R17.

Lift+0.02″
Width−0.79″
Speedometer0.2% 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 305/70R17 and uses the revolutions per mile the makers publish: at an indicated 60 mph you'd be doing 60.1 mph.

Side by side

305/70R17285/75R17Difference
Listed height ″33.86–33.9033.80–34.09+0.03
Size code height ″33.8133.83+0.02
Height under load ″32.832.9+0.1
Width ″12.0111.22−0.79
Listed width ″12.211.3–11.6−0.9
Sidewall ″8.418.42+0.01
Wheel ″1717same
Weight lb64.2–67.759.3–69.0−2.0
Tread depth /32″16–1716–19+0.8
Tires listed39

All 34-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.

Tire305/70R17 ″285/75R17 ″Taller byHeavier by
BFGoodrich All-Terrain T/A KO333.9033.80−0.10″−4.9 lb
Toyo Open Country A/T III33.8633.86+0.00″−4.7 lb
Toyo Open Country R/T Pro33.9033.90+0.00″−0.2 lb

Questions about 305/70R17 vs 285/75R17

How much taller is 285/75R17 than 305/70R17?

0.03″ on average, going by the heights tire makers list: 305/70R17 tires are listed at 33.86–33.90″ and 285/75R17 at 33.80–34.09″. The size codes work out to 33.81″ and 33.83″, a 0.02″ difference.

How much lift does 285/75R17 give over 305/70R17?

Almost none: the tire's radius changes by 0.02″. 285/75R17 is also 0.79″ narrower on paper, 0.39″ per side on the same wheel. Whether it fits depends on your vehicle, lift and wheel offset.

Will my speedometer be off with 285/75R17 instead of 305/70R17?

Barely: about 0.2% slow.

Can 285/75R17 go on the same wheel as 305/70R17?

Both fit a 17-inch wheel. Wheel widths approved for both run from 8.0″ to 9.5″.