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Truck frame question

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  • Truck frame question

    Hey guys, I read this forum almost everyday. I don't post much as what ever question I have has been answered somewhere usually and I don't know a 1/10th as much about welding as most here.

    With the obligatory *** kissing over, here is my question. We have been trying to decide what to do for racecar transport here lately. We're killing my poor little half ton. Right now it is a 20' open trailer. We have thought of the RV route, but that didn't really work either. My last thought was a semi converted into a transport/toter home witht he car rolled in the back. Anyone have any thoughts on this? I'm not sure many have the wheelbase for what I want to do, is it even possible, or plausible to lengthen the frame on a Semi? Would it be strong enough? I have heard people talk about not welding on P/U chassis between the frame rails here and I wondered if it was the same deal? Does it make the metal brittle? Will it crack? I tried to find it here, but I may not have searched the right terms.

    This is at least a year off, probably two, but I wanted to get a little research done early. Thanks in advance you guys!

  • #2
    If you know what you are doing, and engineer the job properly, there is absolutely no problem stretching a truck, either by adding frame onto the back, and moving the axles back, or simply cutting the truck in half, and adding more frame in the middle.


    • #3
      here is a couple of some local racers here in my area.these frames have been welded on.
      Attached Files


      • #4
        Same answer as Calweld.


        • #5
          Having worked for Volvo trucks for 11 years in the education and marketing dept. , developing material for techs, welding on a class 8 truck frame should be approached with caution. The frames on Volvo trucks are made from T1 steel so will need a 10018 rod or better to properly weld, and that does not mean letting the rod sit around getting moisture pickup. To weld to code, these rods are only allowed to be out of the oven for 30 minutes. Hydrogen embrittlement will be your end result if you do not pay attention to procedures, and that means cracking. Many other manufacturers also do some sort of heat treatment to their frames. I would advise getting in touch with the Mfg. of the brand truck you are modifying and get their input. They do not want to see their product in a bad light, [Broken Frame Rails] so they will be willing to help with their Tech/Service support people. Good luck on your project and I hope this is of some help. Paul
          More Spark Today Pleasesigpic


          • #6
            here is a 2 car hauler that has been stretched
            Attached Files


            • #7
              It's definitely doable. Just check around for local regulations as to where the insert has to be located like Calweld mentioned. Some places want it in front of the suspension. Some places want it added to the back and then relocate the suspension. They should also supply you with a diagram showing how the cut lines are to be done. We do everything up here diagonal to increase weld surface area and spread out stress loads. An additional insert is also installed inside the frame rails and bolted through for added strength. Checking around now saves you fines & doing it twice later.

              Off topic (or another angle) check into the prices on used body job moving vans (cube vans) You can rig up a ramp system and just drive your car in there if that fits your plans. We've done it up here. If you keep the GVWR low enough, and have squirt brakes, you shouldn't need to upgrade your license to drive it, or be subject to all the rules & regs of the big iron.

              Just a thought.

              Professional Spark Generator by Trade.


              • #8
                Black wolf and others are correct, a 45 degree splice is common and an internal or external channel extending beyound the joint. make sure that when welding the splicing channel into place, bolting is a good choice, the biggest thing is to not weld across a frame, only weld length wise.
                this same principle is also used when welding on bar joists, never weld across a bar joist only length wise.

                Paul R Brown, I'm surprised when you say that the truck manufactuers will give you information about how to weld on their frames because doing so leaves them open to a law suit.

                Its been my experience that manufacturers of any thing typically dont like to give any information on how to modify their products, I'm not saying I've never gotten any but its been few and far between.


                • #9
                  Corey, if you have a couple years, you really need to spend your time here researching your local area, talking to truckers and welding shops, find somebody who's good and reliable. And you gotta be careful here, in my area one of the biggest shops actually has one of the worst reputations. There's so many things to consider, from where to cut, thickness of glove or insert, where to start/stop glove or insert, where to locate the bolts, how many and what type and location of additional crossmembers, etc. etc. Big thing here is these frames have to flex, the trick is splicing to allow flex without cracks. And one other thing, I have never yet seen a truck with a perfectly straight frame, even right out of the factory, sometimes you end up throwing the string away and just eyeballing it. So it's kind of hard to give step-by-step instructions over the internet. And if you want to do it yourself, ideally you'd find somebody reliable with experience who can help you out, maybe for a few hundred bucks. You don't have your location mentioned, but in this country, at least the states I'm familiar with, there's no regulatory agency that oversees this kind of work, people just do it and put the truck on the road. Only checks here are, the annual terminal inspection, or a scale inspection, or just a roadside stop inspection, and the Highway Patrol isn't qualified to say if you did a good job or not, only thing they're qualified for (and barely) is finding air leaks and cracks.


                  • #10
                    Cal weld ounce again you are right.

                    One would think that they would hire someone like you or me that truly knows how to look for dangerouse things ( Cobbled work )

                    I do alot of custom hitches on motor homes and things of this nature where the is no factory hitch, another thing I do is re installing hitches on mobile homes that are to be towed down south because the parks up here wont let the old ones be resold.

                    Over the years its amazing the work Ive seen out there and how bad some of it is, I'm surprised there arent more fatalities because of this.

                    I was just at a small gas supplier today, Her dad died a few years ago and she has kept the small family business going and she is building a new truck to deliver gas and while I was there chatting she asked me to look at the truck and there was a splice on the side of the frame and who ever did it welded across the frame.


                    • #11
                      this is my favorite bad ride.

                      i also agree with there advice,i have stretched a couple trucks and had great luck with it.the hardest one i have done was to shorten a cab over pete to make a mobile home toter.
                      Attached Files


                      • #12
                        Wow, I didn't really expect al the info
                        I definitley appreciate it though.
                        For the frame welding I have "a guy", the same one that does my chassis stuff for me that I am pretty confident in if he would want to do it when I am ready. I hadn't even considered whether DOT or someone would want to look at it though.
                        I don't quit understand not welding across the frame though? I am assuming, that you would want the welds all running with the frame rails length wise and not perpendicular? I had considered making all cuts on a 45 deg. angle so I did actually have that part right (yay for me!).
                        I am basically thinking about a single car hauler with a small living quarters in the front right now. I considered the cube van also, and also something like a Chevy Kodiak chassis. We're still in the research stage as far as cost, cost to run, etc.

                        Weldingrod, that looks almost exactly like what I am thinking. Now for that

                        I appreciate the good information guys! Maybe by the time I get to do it I'll be a little more confident in my Keep them coming! I can use ll the ideas I can get!