Follow-up on towing a fifth wheel with a tractor

They are bolted on. First a sleeve goes inside the rail, both the original and the extension. Then a plate is put on the outside, all 3 layers are bolted together. Frame rails are hardened steel, they can't be properly welded in the field.

 

They absolutely can. I have photos of several other trucks that have had frames welded that work every day hauling freight. I've even pulled up frame welding procedures from truck manufacturers for welding frame cracks. But there is no welding of brackets and components to the frame. Grade 8 hardware only (unless the brackets were welded to the frame from factory).

Besides, OP said he has a welder friend, not that the truck was going to have anything welded to it. There is likely going to need to be some fabrication work done to mount an RV 5th wheel assembly to a truck frame.

 

There's a fuel tanker company around me that uses truck and trailer sets, single axles on the dolly and the trailer, and they run super singles.

 

First, to the Op. A Class 8 truck I think it's great for what you're going to do. It's way heavy-duty it'll last you a long long time if you start with something good. I assume it has an air ride rear end which is great because you'll be able to ride in comfort.

The Sterling truck cabs are really not known for the best quality or really comfort. I've driven them there okay but you may want to look around for something maybe a little more luxurious. Like a single axle Freightliner FLD or single axle Freightliner anyway or even a Volvo They Ride nicely. If you found a tandem axle truck that you like the front axle can always be removed and you could even sell it. You could even find a sleeper truck that is a tandem and sell the front rear. I don't know if you need or want a sleeper but it is really nice to have when you are traveling.

You have to remember that with a single axle and especially an air ride single axle is very easy to get stuck unless the truck has full locking rears which I don't think a lot of them have that. So you have to be careful where you park and where you go and when it's icy out and gravel and things like that because it is very easy to get stuck.

As far as welding goes you're not supposed to weld onto the frame, meaning if you were going to carry something on the side of the frame you can't weld something to hold it TO the side of the frame. It has to be bolted to the frame and it can't be bolted near the flanges.

However, frames can be welded together when you are extending frames or installing a cut off or whatever it is that you're trying to do. @AModelCat is correct. Generally a sleeve is put inside, the outside is joined together, it's bolted together and welded. There are specifications from the frame manufacturers as to what Rod to use and what not.

With the Class 8 truck you will have plenty of power, you can be gentle on your brakes and they will last you a long long time, and if you take care of your engine you're not really pulling any kind of a load so engine transmission rear and all that stuff will last you. I think it's a very good move.

But like I said, don't be afraid of finding something luxurious. There are really nice trucks out there with really nice interiors that aren't all plastic and that type of thing. I recommend that you go to some kind of a truck dealer and just look around and see if there's some model that you like and then see if you can find that in your price range.

Class 8 trucks are way cooler, more fun-to-drive, roomier, and more comfortable than any pickup or whatever other class truck that you would look at. Just start with something good and you will be all set.

I wish you good luck.

 

I’ve never seen a truck stretched that way, they always weld them around here. I know many that have been done.