tyre numbers

[X-ale]

what do they mean... like: 20/65-18... 18 inch where? diameter?!too small... radiant?! way too huge... large?no... so what?! please help, thx in advance... :?

[stracing]

20 means tyre width form wall to wall, 65 in percentage is the aspect ratio, this is multiplied by the tyre width to give sidewall height. 18 means the rim size.

usually a tyre gives more info. like saying whether its for passenger cars or trucks. or saying the max speed of the tyre

an example of pirelli tires.
215/40 ZR18TL 85W
215 = tread width
40 = sidewall height which is 40% of tread width
ZR = speed category, in this case, ZR means more than 240km/h
18 = wheel size, which is 18 inches in diameter
85W = 85 being percentage and W speed symbol, W means not more than 270km/h with 85% load.

altho i never knew what TL meant, possibly temporary tyres. most tires are radial contruction, so you might not see the R after the aspect ratio.

[RC45]

Width in mm, aspect ratio as percentage of tyre width, wheel diameter in inches.

[X-ale]

thank you both very much

[DeMoN]

pretty informative. Glad I checked here.

[rocket]

actually.. it depends.. if it is road tires then you're correct

but.. that figure he gave is for a racing tire and they do it slightly differently, so
20 is the width(200 mm)
65 is diameter(650 mm)
18 is the wheel size(18 inches)

a road tire uses slightly different way of saying it normally
205/65/18 (doesnt exist AFAIK, but we'll use it as an example anyway)
205 is the width(205 mm - but this is a nominal figure and different makes will be slightly different, also the aspect ratio has some bearing on this making it wider/narrower - but onyl by a few mm)
65 is the sidewall height or aspect ratio, and it means the sidewall is 65% of the tire width
18 is the wheel size(18 inches)

[X-ale]

man whos the genius that decided to blend mm and inches.... well as long as it works right, thx Dan

[stracing]

yea but everyone got used to it. we use the metric system, yet we still use inches for wheel size. doesn't everybody else find the metric system a lot easier. everything just goes up by ten to the power of n.

[b69]

stracing metric here... go figure those bodyparts fanatics... inch, foot.... what is this :P
lot easier metric i think also

by the way thanks for the information... nice i checked it out...

[Wutputt]

altho i never knew what TL meant, possibly temporary tyres.
TL = Tubeless ;)