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Tire size

275/40R18 tire size: dimensions explained

Factory size on the BMW M3 (G80), BMW M4 (G82). 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 width275 mm10.83 in
Sidewall height110 mm4.33 in
Overall diameter677.2 mm26.66 in
Wheel diameter457.2 mm18 in
Circumference2129 mm83.8 in
Revolutions per mile756

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

Reading the marking

275 is the section width in millimetres, 40 is the sidewall height as a percentage of that width, R means radial construction, and 18 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 275/40R18 with another size →

275/40R18 tires at Tire Rack

All-season

TireLoad/speedPrice per tire
Yokohama ADVAN Sport A/S+
Ultra High Performance All-Season		99Y$169.90View at Tire Rack
Kumho Majesty 9 Solus TA91
Grand Touring All-Season		XL 103W$212.70View at Tire Rack

Summer performance

TireLoad/speedPrice per tire
Nexen N FERA SU1
Ultra High Performance Summer		XL 103Y$136.56View at Tire Rack
Sumitomo HTR Z5
Ultra High Performance Summer		XL 103Y$192.99View at Tire Rack

Winter

TireLoad/speedPrice per tire
Pirelli Winter Sottozero 3
Performance Winter / Snow		XL 103V$247.85View at Tire Rack
Vredestein Wintrac Pro+
Performance Winter / Snow		XL 103Y$259.93View at Tire Rack

Showing the lowest-priced in-stock options in each category from 22 275/40R18 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