Upgrade tires for better mileage?

Have a '96 Cherokee 4.0 auto running on the BF Goodrich A/T KOs, and I'm thinking about changing over to a street tire, if and only if it will save me the cost in gas over the next two years that it costs to buy em.

So what's the popular opinion? Will a set of say Michelin LTS M/S Highway All Seasons save me say $600 over the next two years, over my BFG A/T KOs?

I drive about 12K miles a year 99.9% on pavement.

Let's say that right now you get 16 mpg's (which is pretty standard) if you drive 12K a year that amounts to about 750 gallons of gas per year that you will have to buy. At the current rate of $4.00 per gallon average that equals out to $3k a year in fuel costs. If your new tires allowed you to get 2 more mpg's (not sure if this is close or not, but it gives you something to look at) it will save you $334.00 a year. Of course this is all assuming that the new tires will allow you better mpg. Hope this helps.

I'm running kumho m+s on 16'" silverstars. not sure how much more economical they are but they are super quiet on the highway and siped well. under 400 clams if i recall correctly.

There was an article in 4Wheel Drive & Offroad about this. They compared the Michelin LTX against the Dick Cepek FC2 in the same size and on the same factory wheels. The street friendly Michelin got almost 2 mpg better the FC2's. This was tested on a late model F150.

I went from a straight ribed hard rubber compound hiway tire to an AT style tread with same outside dia. and lost an average 1-2 mph on hiway. The biggest change in mpg with my XJ came with what I had mounted on the outside and/or how much junk(weight) was in the back. So now I only carry what I need as a DD. spare, jack and 2 qts of oil. I read some test that were also done with F 150s. They changed tires, bed covers, air gates. tailgates, etc. Somethings minor improvements. But the biggest single was removing the 150lbs crossbed toolbox and tools.