I'm reading all the post on what speed "most" motorhome drivers travel at & I am amazed that most are stating they drive between 60 & 65 mph.
I have a 2001 35" Winnie Adventurer gasser, 8.1L Vortec, Allison 5 speed & 2002 Jeep Wrangler TOAD. We just returned from a month traveling from the Houston area to Yellowstone via interstates for the most part & returning along 287 (Houston-Amarillo-Fort Collins-Jackson Hole-YS). Anyway, that was about 4000+ miles & a pretty good cross section of roads & drivers as of June/July 2018.
Almost to a driver of motorhomes Gas & DP (most were DP) few if any drove 60-65. I was blown by by everyone. Some gassers struggled to pass me because they didn't have the HP but they did anyway.
The speeds were in the 70s at a minimum & must have averaged close to 80. The new DP (pick-ups pulling behemoth rigs & class A motorhomes) all were flying by. I have to say I was impressed with the performance of these machines but astonished at the foolishness of the drivers.
Driving through the mountain passes in Wyoming along 287 I did wish I had a diesel. Two passes in particular were at almost 9000 feet & the Winnie could just make it but performed at keeping to 60-65mph otherwise with no problem, the diesels ran the left lane no problem mon.
My point is that just because you can doesn't mean you should. I just replaced all the tires with Michelin's so I'm good to go for a while but the speed rating on these best in class tires for a class A motorhome is not 80mph +. At 22000# the faster you go the more unstable the rig is & if a tire has a slow leak going faster then the tire was designed for only multiplies the potential for catastrophic failure of tire & rig.
I can remember only once that another class A fell in behind me (2-3 MH lengths) & we cruised the open spaces at 65 for an hour or so. But he too ran past me after that. I would have liked to have traveled with all the folks here that have stated they drive 60-65 (some even at 55
) but I didn't see any of y 'all.