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Tire size

305/30R20 tire size: dimensions explained

Factory size on the Chevrolet Corvette (C8). 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 width305 mm12.01 in
Sidewall height91.5 mm3.6 in
Overall diameter691 mm27.2 in
Wheel diameter508.0 mm20 in
Circumference2172 mm85.5 in
Revolutions per mile741

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

Reading the marking

305 is the section width in millimetres, 30 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 305/30R20 with another size →

305/30R20 tires at Tire Rack

All-season

TireLoad/speedPrice per tire
Bridgestone Potenza RE980AS+
Ultra High Performance All-Season		XL 103W$312.22View at Tire Rack
Falken Azenis FK460 A/S
Ultra High Performance All-Season		XL 103Y$331.00View at Tire Rack

Summer performance

TireLoad/speedPrice per tire
General G-MAX RS
Ultra High Performance Summer		XL 103Y$333.99View at Tire Rack
Toyo Proxes Sport 2
Ultra High Performance Summer		XL 103Y$342.86View at Tire Rack

Winter

TireLoad/speedPrice per tire
Michelin Pilot Alpin PA4
Performance Winter / Snow		XL 103W$536.37View at Tire Rack

Showing the lowest-priced in-stock options in each category from 18 305/30R20 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