i have a sterling tractor converted/stretched to a 10-wheeler, and would not do it again. At the time, I thought it was a good idea, and the owner of the company I was leased to advised against it.I have hauled maybe 5 loads where it was called for over a 5-year period.The extra costs such as heavier plates,tolls,tires,brakes,truck washes(yes, blue beacon charges extra for that extra axle on a straight truck!)etc,just is not worth it. The only advantages that I can see are the extra stabitity,braking when having a normal d-unit load on of 10-13k.And the extra drive axle is also an advantage in the snow.My truck weighs 14,200 on the steer, empty, full of fuel (400 gal capacity).I had the front suspension replaced and upgraded to 18,000k suspension when I bought the truck.upgraded the front tires as well.oregon is the only state that gave me a warning as to the weight rating was not high enough on the 16-ply tires.total weight of this truck is at 29,000 empty.it has a c-15 cat, 550 hp, so I guess that has something to do with it as well.a sterling was always known as a heavy tractor anyways.but all in all, I would not do it again, and would stick with a single-axle straight.