I worked a linkbelt crane back in the 80's with a 555 and 13 speed. It grossed 58,000 lbs. down the road. Top end was 65 mph. If you hit a hill you tried to grab at least 2 gears to maintain some speed. It did do good for the stationary work it usually did on the job sights. It spent a lot of time maxed out on rpm's pouring concrete or slinging iron. I think we overhualed it once.