tireheight.com285/70R17 vs 275/70R18
275/70R18 is 0.4″ taller than 285/70R17 on average, going by the heights their makers list (32.9″ vs 33.3″). On paper the gap is 0.45″.
What changes
Going from 285/70R17 to 275/70R18.
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 and uses the revolutions per mile the makers publish: at an indicated 60 mph you'd be doing 60.7 mph.
Side by side
| 285/70R17 | 275/70R18 | Difference | |
|---|---|---|---|
| Listed height ″ | 32.70–33.15 | 33.19–33.58 | +0.40 |
| Size code height ″ | 32.71 | 33.16 | +0.45 |
| Height under load ″ | 31.8 | 32.2 | +0.4 |
| Width ″ | 11.22 | 10.83 | −0.39 |
| Listed width ″ | 11.4–11.6 | 10.8–11.3 | −0.5 |
| Sidewall ″ | 7.85 | 7.58 | −0.28 |
| Wheel ″ | 17 | 18 | +1 |
| Weight lb | 46.0–65.7 | 40.3–66.0 | −1.3 |
| Tread depth /32″ | 13–19 | 12–20 | −0.4 |
| Tires listed | 36 | 32 |
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.
| Tire | 285/70R17 ″ | 275/70R18 ″ | Taller by | Heavier by |
|---|---|---|---|---|
| BFGoodrich All-Terrain T/A KO3 | 32.80 | 33.20 | +0.40″ | +3.8 lb |
| BFGoodrich HD-Terrain T/A KT | 32.80 | 33.20 | +0.40″ | −1.6 lb |
| BFGoodrich Mud-Terrain T/A KM3 | 32.80 | 33.20 | +0.40″ | −1.5 lb |
| General Grabber A/TX | 32.70 | 33.20 | +0.50″ | −4.6 lb |
| General Grabber APT | 32.70 | 33.20 | +0.50″ | −11.1 lb |
| General Grabber X3 | 32.70 | 33.20 | +0.50″ | +0.1 lb |
| Michelin Defender LTX M/S 2 | 32.80 | 33.20 | +0.40″ | −1.5 lb |
| Mickey Thompson Baja Boss A/T | 32.90 | 33.40 | +0.50″ | +10.5 lb |
| Mickey Thompson Baja Legend EXP | 33.10 | 33.40 | +0.30″ | −2.0 lb |
| Mickey Thompson Baja Legend MTZ | 33.00 | 33.30 | +0.30″ | −2.0 lb |
| Toyo M-55 | 33.15 | 33.58 | +0.43″ | +2.4 lb |
| Toyo M655 | 33.07 | 33.58 | +0.51″ | +1.8 lb |
| Toyo Open Country A/T III | 32.81 | 33.19 | +0.37″ | +0.3 lb |
| Toyo Open Country C/T | 32.99 | 33.42 | +0.43″ | +0.0 lb |
| Toyo Open Country H/T II | 32.76 | 33.19 | +0.43″ | −0.6 lb |
| Toyo Open Country M/T | 32.99 | 33.57 | +0.58″ | +1.0 lb |
| Toyo Open Country R/T Pro | 32.76 | 33.20 | +0.44″ | +2.0 lb |
| Toyo Open Country R/T Trail | 32.76 | 33.19 | +0.43″ | +1.1 lb |
| Toyo Open Country WLT1 | 32.84 | 33.27 | +0.43″ | +0.4 lb |
Questions about 285/70R17 vs 275/70R18
How much taller is 275/70R18 than 285/70R17?
0.40″ on average, going by the heights tire makers list: 285/70R17 tires are listed at 32.70–33.15″ and 275/70R18 at 33.19–33.58″. The size codes work out to 32.71″ and 33.16″, a 0.45″ difference.
How much lift does 275/70R18 give over 285/70R17?
The tire's radius grows by 0.20″, so the axle sits about 0.20″ higher, and the top of the tread comes 0.20″ closer to the fender. 275/70R18 is also 0.39″ narrower on paper, 0.20″ per side on the same wheel. Whether it fits depends on your vehicle, lift and wheel offset.
Will my speedometer be off with 275/70R18 instead of 285/70R17?
Yes. If it's set for 285/70R17, it will read about 1.2% slow: at an indicated 60 mph you'll be doing 60.7 mph. Worked out from the revolutions per mile the makers publish.
Can 275/70R18 go on the same wheel as 285/70R17?
No. 285/70R17 fits a 17-inch wheel and 275/70R18 a 18-inch wheel.