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      12-04-2011, 07:00 PM   #16
///M Rakete
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Drives: BMW 2010 M3 Coupe
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Quote:
Originally Posted by VVG View Post
Not true. Here's the math:

245/35/19:

19" wheel = 482.6mm
sidewall = 245 x 0.35 = 85.75mm

total diameter = 482.6 + (85.75 x 2) = 654.1mm

285/30/19:

19" wheel = 482.6mm
sidewall = 285 x 0.30 = 85.5mm

total diameter = 482.6 + (85.5 x 2) = 653.6mm

255/30/19:

19" wheel = 482.6mm
sidewall = 89.25mm

total diameter = 482.6 + (89.25 x 2) = 661.1mm


The 245/35 and 285/30 are within 0.5mm of each other. the 255/30 is 7mm larger.
Tire manufacturer dimension markings are nominal values. You should always use the manufacturer's actual specifications for a given "size". According to Pirelli the 255/35-19 and 285/30-19 have the same overall outer diameter at 26".
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