I have to go with if U do not think its safe do not do it, BUT it is done daily on our roads thru out the world, five tons towing 5 tons and deuces towing deuces, and like so well said above about it is done all the time, a five ton will stop a 5 ton very very nicley, i say this because years ago, and i always say to do this in these threads, before going out on the road connect both trucks touch every conection drive a short distance hit the brakes good, touch everything again, take the unit to a large area and get going 20 to 25 and NAIL the brakes as hard as u can, it will teach U more than any one anywhere can. then check out your trucks, are u scared or OK I can handle that, my experience of practice runs years ago, and over the road experiences say the 5 ton is more than a match to tow another 5 ton, the air conections are the way to go, but really i have to say it depends on how far, are the roads highway, alot of traffic, hilly etc, all make my decisions. Now i am lucky to say i have 20 ton loads under my belt driving tandems years ago for summer jobs, but U have to get experience somewhere, its up to you really, U sound reasonable ,and i am honest about that, are u strong enough to hold that truck straight in a difficult situation? The speeds u should be driving a 5 ton will stop u just fine, expecially with the air hooked up. alot of guys say they do sixty with those ruper singles, and will say what u want to do is dangerous, now that sounds silly to me. so i believe it is an opinion from the other posts about what a 5 ton will post by writing numbers down on paper, I know it works.