I am new on that forum and we intend to buy a 30 or 32 or possibly 34 feets fifthwheel. We also have to buy a truck to tow it. We have heard that it in many countries it is obligatory to have a double rear-wheels when you tow a big fifthwheel. Is it true??? If not, how can I be sure that it is really not necessary because I do not want to buy a truck that does not allow me to go everywhere. If we talk about single rear-wheels, what is the best F250 or F350. Diesel or gaz? Is it more dangerous for jackknife with single RW. I know that both have the power to tow the kind of fifthwheel I want but does it just support it easily. Will the back of the truck be weighted down with just a F-250 SRW? Also, is it better to take a 6.5 feets or 8 feets box? Thanks a lot!