Tires designed for Mhs such as the GY670 and some Michelins and others do not have the ultra stiff sidewall necessary for a 1100,000.00 lb semi.
As such the MH designated design tires will ride softer.
Some the big Coaches call for a heavier tire perhaps, and even for annual replacement of the steer tires.
The Michelins in the Mh tires are softer sidewalls than the G670s.
We got some of th first of the new design and the molds were new. Only took an ounce on one rim and none on th other on steer axle, on a road force balancer.
As molds get older they distort from heat and use. Just somehing else we can't do much about.
At this point I would have to reccomend the Michelins for the steer axl and G670s for rear axles. Reason the G670s still want to river on steer axle.
The G70s they pulled off our rear after 13 years wre as soft and pliable and devoid of wear, I kick myself for replacing them. The Goodyears have/had more uv protectant in the rubber but are stiffer than the Michelins in same ply tire.