On Tue, 23 Dec 2008 09:43:45 -0500, Van Chocstraw
wrote:

Van Chocstraw wrote:
wrote:
On Sun, 21 Dec 2008 19:35:08 -0800 (PST), wrote:

For example: 20x10-8. What exactly do these numbers mean and do I
have to get the exact size that comes with my tractor or can I get a
tire that is not as wide? Thanks
20 inch outside diameter, 10 inches wide, on an 8 inch rim.

I don't think you mean DIAMETER.
It's width.

Never mind. I guess it's OD, screwy way to do it.


In racing that kind of sizing made it very easy to figure out final
gearing, and to set stagger for circle tracks.
In offroad vehicles it makes it very easy to calculate, again,
gearing, but also ground clearances.
You KNOW, just from the first number of the tire size what the running
diameter of the tire is - you have 25" tires on your race car and it
is running 6000 RPM down the straight in top gear. You want it to run
7000 RPM - what size tire do you need? You want a tire 6/7ths the size
of your current tire - or 25X6/7+ 21.45 inches.