Okay so I'm looking for tires/rims and basically my question is a really simple one that I'm sure qualifies me as a dumbass but whatever haha.

okay so when they give you a tire size, it's three numbers like 245-40 18

Now so far I think i have figured out that the third number is for the diameter of the rims that will fit it, Right?

So what do the other two numbers mean?

 

width/sidewall-diameter

you can find stuff like this on tire sites like discount tire, Big-O and the like.

 

Excelent, thanks a lot, especially not for flaming me for being stupid haha.

but i did try and find that on discounttire.com but couldn't find anything, oh well, now I know, THANKS

 

For future reference, ANYTHING you wanted to know about tires can be found here...

http://www.tirerack.com/tires/tiretech/tiretech.jsp

Discount Tire's Info Center has similar stuff...

http://www.discounttiredirect.com/di...InfoCenter.jsp

 

The metric tire sizing system represents a tire size as:
[section width (mm)] / [aspect ratio] - [rim diameter (inches)]

For example: A tire size 225/45-18 is 225mm wide, has an aspect ratio of 45 and fits an 18" rim (wheel).

The aspect ratio (the second number) is not a measurement. The aspect ratio represents the tire's sidewall height as a percentage of the tire's width (section height divided by section width). In the example above, the sidewall height is 101mm (101/225=45).

The aspect ratio is important since that (along with the wheel size) determines the overall diameter of the tire allowing you to match your stock overall tire height (diameter). For example, a 225/45-18 tire's sidewall height is 101mm, and a 245/40-18 tire's sidewall height is 98mm. So, both tires have nearly the same overall diameter.

--Spike