RightTread

Tire size

285/40R20 tire size: dimensions explained

Factory size on the Porsche Taycan. Below are the dimensions calculated from the size marking itself. Your vehicle's correct size, load index and speed rating are on the placard in the driver's door jamb; check it before buying.

MeasurementMetricImperial
Section width285 mm11.22 in
Sidewall height114 mm4.49 in
Overall diameter736 mm28.98 in
Wheel diameter508.0 mm20 in
Circumference2311 mm91 in
Revolutions per mile696

Calculated values: diameter = wheel + 2 × (width × aspect ratio). Real tires vary slightly by brand and model.

Reading the marking

285 is the section width in millimetres, 40 is the sidewall height as a percentage of that width, R means radial construction, and 20 is the wheel diameter in inches. A passenger (P or Euro-metric) tire and an LT tire in the same size are not interchangeable without checking load requirements.

Compare 285/40R20 with another size →

285/40R20 tires at Tire Rack

All-season

TireLoad/speedPrice per tire
Continental ProContact GX
Grand Touring All-Season		XL 108H$332.77View at Tire Rack
Goodyear Eagle F1 All Season
Ultra High Performance All-Season		XL 108Y$384.99View at Tire Rack

Highway / touring

TireLoad/speedPrice per tire
Kumho Crugen GT Pro
Crossover/SUV Touring All-Season		XL 108W$233.54View at Tire Rack

Summer performance

TireLoad/speedPrice per tire
Yokohama ADVAN Sport V107E
Max Performance Summer		XL 108Y$167.23View at Tire Rack
Bridgestone Turanza 6
Grand Touring Summer		XL 108Y$197.92View at Tire Rack

Winter

TireLoad/speedPrice per tire
Pirelli P Zero Winter
Performance Winter / Snow		XL 108V$206.52View at Tire Rack
Vredestein Wintrac Pro+
Performance Winter / Snow		XL 108W$260.79View at Tire Rack

Showing the lowest-priced in-stock options in each category from 37 285/40R20 tires in Tire Rack's feed, sorted by price only. We don't rank by commission. Match or exceed the load index and speed rating on your placard.

Affiliate links: if you buy through a Tire Rack link, RightTread may earn a commission through CJ. It doesn't change your price. Prices are Tire Rack's per-tire prices from Tire Rack's product feed as of Nov 7, 2026, 9:19 PM PT. Prices change, so confirm on Tire Rack before you buy. Disclosure

Other sizes