I've got 235/ 70/16's on my Disco 1 right now which is what is called for. Can someone give me a quick run down on what these 3 sets of numbers means and what I can use in tire size without significantly upsetting pick up and mpg. Stock ride height also with a possible 2" Fj spring lift in the future.

As an example we'll start with these.
http://myrtlebeach.craigslist.org/pts/2355551489.html
285/70/17

 

First number is max bulge width, in millimeters.
Second number is height as a percentage of max width.
last number is rim diameter.



The pic incorrectly labels the first number as tread width, which is not quite accurate.

 

so I have to get this exact width and rim size tire but I can get one a little taller? I'm trying to save money and I'm not about to waste $800 on tires on it.

 

If you've got 16 inch diameter wheels, you'll need 16 inch tires. The other numbers usually have a range of wheel sizes that work. The stock disco 1 wheel is 7 inches wide, the heavy duty wheels come in a couple of widths. If you go to tirerack dot com and search for a tire you want (even if you don't want to buy it there) you can click on specs, and it will show what the maker of the tire suggests for rim width. You also need to be concerned about what will fit under your truck.... whether it will rub, how much lift or trimming you need to do.

I personally think taller tires like 235/85R16 look good on the disco 1, but some people prefer a tire that's taller and wider than stock, like a 245/75R16 or 265/75R16. Some of those sizes will certainly require work, and aren't just a install the tire and go type of deal.

 

As a general rule of thumb you can plus or minus one size with no problems.
Some cars you must use the OEM size because of clearance issues, my wifes Volvo is like that, but not our Rovers.

 

What spike said. My disco 1 had 245/70R16, with worn out, sagging, stock springs, and no adjustments whatsoever. (some people have to adjust steering stops.).

 

they are rated correctly for the weight though! Most of the trucks I have seen have been driving around on 103 and 104's, like I was, and TEARing out the sidewalls because of how heavy our trucks are.

I now have the 110 rated "Light Truck" tires - and happy as a clam.

I did cost me a little more, but well worth it.

This site is a WEALTH of information:

SecuritDriver.Com - Articles - Basic Tire Information Where the rubber meets the road...

 

Is found this in another thread.... Super helpful
http://www.members.shaw.ca/jbarge/tires.html