2012 Polaris 850 xp gear reduction

I have an O12 850 xp and the silent chain is broke and sprocket is stripped.
So, I do mostly trail riding and right now it has stock tires. I am going to get probably some 27-28 outlaw radials, not going to deep in mud. I will use it to pull a 1500lb trailer and a 2500lb sawmill around, not very often though. The fastest I will ever want to go is 65mph at the most but will try to get there as fast as possible. So should I get a gear reduction for it?