275/60R20 is 0.2″ taller than 285/70R17 on average, going by the heights their makers list (32.9″ vs 33.0″). On paper the gap is 0.28″.
Going from 285/70R17 to 275/60R20.
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 60.2 mph.
| 285/70R17 | 275/60R20 | Difference | |
|---|---|---|---|
| Listed height ″ | 32.70–33.15 | 32.90–33.40 | +0.16 |
| Size code height ″ | 32.71 | 32.99 | +0.28 |
| Height under load ″ | 31.8 | 32.0 | +0.1 |
| Width ″ | 11.22 | 10.83 | −0.39 |
| Listed width ″ | 11.4–11.6 | 10.8–11.0 | −0.5 |
| Sidewall ″ | 7.85 | 6.50 | −1.36 |
| Wheel ″ | 17 | 20 | +3 |
| Weight lb | 46.0–65.7 | 34.3–64.0 | −10.3 |
| Tread depth /32″ | 13–19 | 10–19 | −3.1 |
| Tires listed | 36 | 30 |
The same model in each size, by the heights the maker lists. Averages where a model comes in several load ranges.
| Tire | 285/70R17 ″ | 275/60R20 ″ | Taller by | Heavier by |
|---|---|---|---|---|
| BFGoodrich All-Terrain T/A KO3 | 32.80 | 33.00 | +0.20″ | +2.3 lb |
| BFGoodrich Trail-Terrain T/A | 32.80 | 33.00 | +0.20″ | −0.3 lb |
| BFGoodrich Trail-Terrain T/A+ | 32.80 | 33.00 | +0.20″ | +1.8 lb |
| General Grabber A/TX | 32.70 | 33.00 | +0.30″ | −4.3 lb |
| General Grabber APT | 32.70 | 33.00 | +0.30″ | −14.9 lb |
| Michelin Defender LTX M/S 2 | 32.80 | 33.00 | +0.20″ | −12.1 lb |
| Mickey Thompson Baja Boss A/T | 32.90 | 33.40 | +0.50″ | +0.0 lb |
| Mickey Thompson Baja Legend EXP | 33.10 | 32.90 | −0.20″ | +2.0 lb |
| Toyo Open Country A/T III | 32.81 | 32.99 | +0.18″ | −4.2 lb |
| Toyo Open Country H/T II | 32.76 | 32.99 | +0.24″ | −4.2 lb |
| Toyo Open Country R/T Trail | 32.76 | 32.99 | +0.24″ | −10.3 lb |
0.16″ on average, going by the heights tire makers list: 285/70R17 tires are listed at 32.70–33.15″ and 275/60R20 at 32.90–33.40″. The size codes work out to 32.71″ and 32.99″, a 0.28″ difference.
Almost none: the tire's radius changes by 0.08″. 275/60R20 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.
Barely: about 0.4% slow.
No. 285/70R17 fits a 17-inch wheel and 275/60R20 a 20-inch wheel.