I used to run 38.5X14.50 SXs on 8 inch rims, they were fine off road, but literately was horrible on the road. I like my 10s much better on and off road. I run 3-5lbs consistently on snow and rocks and have never popped a bead on the 10s I have now...
The 8s made the tire to rounded, they didn't get much traction on the rocks because they were so rounded,
I used to drive them around the yard with the valve stems out and they were just about right,,, on the 8inch rims that is
The tires might act a little different with a sidewall a little less tough than the SX's
