I have discussed it with colleagues - now I understand relation between tire weight and suspension. You are wright, I was wrong.
So, I searched for lightest tires. Went thru lots of tires (find that just a few are radials). Finally find Maxxis Zilla and Carlisle 489. Then I looked at the prices of tires. Were socked :-O Set of Maxxis Bighorn 3.0 (26x9 and 26x11) or Carlisle A.C.T (26x8 and 26x10) cost about 600€!!
But then I found offer for set of Maxxis Zilla (25x8 and 25x10) for just about 275€ and Carlisle 489 even about 45€ less.
On the other hand I found used (500km, unmounted from new CanAm Outlander) set of Carlisle A.C.T (26x8 and 26x10) for 300€.
Here are the weights I have found:
1) stock Maxxis M975 and M978 = 14,0 and 17,5 lbs
2) Carlisle 489 (25x8 and 25x10) = 14,1 and 16,8 lbs Even lighter then stock!
3) Maxxis Zilla (25x8 and 25x10) = 14,8 and 18,3 lbs Just a little heavier then stock.
4) Carlisle A.C.T (26x8 and 26x10) = 18,0 and 23,9 lbs About 1/3 heavier then stock.
So, now I don't know what to buy
Why they made so lots of tires!! If there will be only one, I will know what to buy