used tires
12-21-2012, 05:24 PM
#16
Rennlist Member
We also have several sets of 1-2 cycle env2 yoko's. autometrics@me.com if anyone is interested. I think we also have a set of Michelin n1's as well. Great for test or practice days
12-24-2012, 11:18 AM
#17
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im the original poster of this link, enjoy all the feedback and sources....last dumb question, can someone tranlsate tire sizes for me...so a 325/50 18 on a street car, what does that, or any size convert to for a race tire for example a 240/640 18
12-24-2012, 12:06 PM
#18
Rennlist Member
The first number in both sequences refers to the width of the tire in millimeters, so in the samples above the street tire would be 325mm wide and the race tire 240mm wide. The last number in the sequences are also the same, in this case both refer to 18" wheels.
The middle number is where the difference is. On the street tire it refers to the "aspect ratio" so in your sample the "50" refers (loosely) to the tire sidewall height being 50% of the tire width. To determine the overall height of that tire you'd have to refer to the manufacturer's spec sheets. On the race tire the second number is the overall height of the tire. In your sample that would be 640mm or in most cases it would be 64 or 64 cm.
240/64/18
Width = 240 mm
Height = 640 mm (64 cm)
Wheel = 18"
It's a very good system it alleviates the need to scurry back to tirerack.com all the time to look up the tire heights which can vary significantly between manufacturers for tires that have the same width and aspect ratios.
The middle number is where the difference is. On the street tire it refers to the "aspect ratio" so in your sample the "50" refers (loosely) to the tire sidewall height being 50% of the tire width. To determine the overall height of that tire you'd have to refer to the manufacturer's spec sheets. On the race tire the second number is the overall height of the tire. In your sample that would be 640mm or in most cases it would be 64 or 64 cm.
240/64/18
Width = 240 mm
Height = 640 mm (64 cm)
Wheel = 18"
It's a very good system it alleviates the need to scurry back to tirerack.com all the time to look up the tire heights which can vary significantly between manufacturers for tires that have the same width and aspect ratios.
12-24-2012, 12:49 PM
#19
Also note that for race tires the first number is generally the tread width whereas street tires it's the overall width. So a 27 Michelin it's a whole lot wider than your average 275 street tire.
