Hi, I just bought my first SUV, a 2008 LX570. So far so good and no post purchase issues seen yet; I'll bringing it into the shop for inspection soon.

Question: it came from the used car dealer with Cooper HT Plus tires (285/50/20 with A B traction / temp rating). The tires seem generally well reviewed. However, with the heat these days, after about a 1 hour drive, I noticed the pressure went from 33psi to about 38psi. When I stopped, the tires were very hot to the touch.

1) What is the stock tire: 285/50/20 (traction) (temp) (load) (speed) rating?
2) Any recommendations for what tire to use going off pavement (sand/gravel/mud trails; river and lake side for kayaks); not planning to go really offroad and climb rocks. But some trails and going near the water might be a little rough. Do I need to change wheel size?

Also, trips will be occasional -- Any recommendations on how to keep 4L and the center diff in work working order between trips? I know we're supposed to exercise it once in awhile. But how frequently and what's the best way?

Thanks.

 

I'm getting BFG AT/KO2 275/55/20