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schwank · 11-30-2007, 01:41 PM

Actually the 225 and 245 are the width of the tire.

Tire sizes work like this

225/40 - 18

tire width (millimeters)/tire sidewall height (% of width) - wheel diameter (inches)

So a 225/40 is 20mm narrower than a 245/40.

Each tire has a sidewall 40% of the width.

So 225/40 = 90mm sidewall height
and 245/40 = 98mm sidewall height

HERE is a link with more explanation, or just google 'tire size explanation'

11-30-2007, 01:41 PM	#4
schwank Registered User Join Date: Nov 2007 Location: Portlandia Posts: 53	Actually the 225 and 245 are the width of the tire. Tire sizes work like this 225/40 - 18 tire width (millimeters)/tire sidewall height (% of width) - wheel diameter (inches) So a 225/40 is 20mm narrower than a 245/40. Each tire has a sidewall 40% of the width. So 225/40 = 90mm sidewall height and 245/40 = 98mm sidewall height HERE is a link with more explanation, or just google 'tire size explanation' __________________ life is participation in evolution 87 944 PRO44 racer. 01 986S (race build in progress), 93 968