RV frame extension reinforcement for towing

Discussion in 'General' started by gapman789, Dec 4, 2020.

  1. gapman789

    gapman789 Well-Known Member

    So my 05 Winnebago Aspect 26a on an E450 chassis (1.5 ton) has a towing capacity of 5000 lbs/350 TW. With my enclosed trailer and 3 bikes, i'm at the limit. Also with my SxS in an enclosed trailer.

    It seems fairly common to have the rear subframe/frame extensions reinforced and a higher rated hitch installed......Very popular in the drag racing scene with people pulling 20'+ enclosed trailers with their RV's.

    Anybody have lst hand experience doing this? Any tips or pointers? Maybe understandably, but I can't seem to find an "RV" place to do this, so a professional welding/fab shop would have to do it. There's all kinds of room and looks fairly straight forward. ' motorhome subframe beefup' on youtube shows this at TORKLIFT in Washington St. A bit far to drive from Ohio.

    I understand the legailites of towing over the specified tow rating of the RV, etc....Having the work certified is beneficial in this case.

    I don't plan on towing over 5000 lbs necessarily, but being at the limit and hitting bumps, uneven transitions of pavement at bridges, etc, could create some damage over time. Just trying to be proactive and give myself a little peace of mind.
  2. TurboBlew

    TurboBlew Registers Abusers

    wouldnt it be easier to get a lighter trailer?? On my 35' class A the gvcw is 26,000lbs max... so that typically leaves 4500 lbs for the trailer. More if theres less people & water. Have you weighed the coach?
  3. gapman789

    gapman789 Well-Known Member

    Cant get much lighter than a 7x16.

    I only know the weight of the rv from the spec ‘sheet’.
  4. zertrider

    zertrider Waiting for snow. Or sun.

    The weight on the sheet in the cupboard is usually pretty accurate with Winnebago. As for reinforcing the frame, tongue weight is more to worry about than total. Any reinforcing does not have tobe certified. Just keep the combo below the GCWR. If it doesn't already have them, install rear air bags, as the 26a tends to sit low at the rear. N
  5. ducnut

    ducnut Well-Known Member

    Nice motorhome.

    IMO, you’re overthinking this.

    There’s little comparison between pulling a 20’/24’ X 8.5’ at ~3700# empty weight, loaded with a 3500# car, tool chest, and whatever else a drag racer takes to the track. Those guys are notorious for overloading everything, especially the tongue, because they don’t want to spend/don’t have the money to buy the right equipment, in the first place. They’ll buy the cheapest trailer, with 2 X 3500# axles, load them to 8K-10K pounds, and wonder why they have issues with blowouts, axles bending, trailer falling apart, etc. Even worse, they’ll pull it all to the track with a 1/2T pickup. You’re a much smaller operation, just creeping up on the manufacturer’s recommended ratings.

    Adding frame reinforcements is only adding weight to an already tail-heavy motorhome. I wouldn’t do it.

    I agree with “zertrider”, installing airbags will help with supporting the rear of the motorhome. Motorhomes are notoriously heavy over the rear axle. The good thing is that weight is distributed along the length of the frame rails. I have an auto ride-height setup on my pickup and it totally changed my towing/hauling experience. I can’t recommend an airbag system enough.

    In addition, Blue Ox sway bars (F&R), Blue Ox rear track bar, and Bilstein’s shocks valved for the long wheelbase applications will totally transform the handling of your motorhome. Beyond that, Roadmaster’s steering stabilizer is highly regarded.

    You could revise your trailer setup. An all aluminum unit can save a few hundred pounds. A trailer with torsion axles better supports the carried weight, easing tongue weight. I’ve pushed around a 7’ X 14’ torsion trailer, with the tongue jack completely off the ground. Pay close attention to how you load your trailer. Shifting weight toward the rear will help ease tongue weight. Just be careful to not shift too much weight where you get yourself into trailer swaying issues.
  6. TurboBlew

    TurboBlew Registers Abusers

    whats the trailer weigh? My 7x20 is 2700lbs by itself. Aluminum version is 1450lbs empty

    I would weigh the rig first... fully loaded. Water, fuel, and propane.
    ducnut likes this.
  7. fastfreddie

    fastfreddie Midnight Oil Garage

    Your tow rating is more about engine output and transmission torque rating than chassis capacity. I'd bet that same identical chassis can be found in a '15+ RV that has higher tow ratings simply because the engine and/or transmission are uprated.
    I mean, seriously, think about it. You can't hang more than 5000lbs off the ass end of an F450 chassis? BS.
  8. Phl218

    Phl218 Lemme ask my wife

    i think even more about brakes than engine... because you can go up the hill as slow as you want, but you definitely want to get the rig stopped.

    but yeah, a 450 should easily be capable of what you're looking into.
    YamahaRick likes this.
  9. metricdevilmoto

    metricdevilmoto Just forking around

    I have an 03 E450 17' box truck. After I pulled off the lift gate, I had a class 5 hitch added and the frame boxed (basically doubled up on the mounts for the hitch) and have had zero issues for years pulling a lot more than 5000 lbs over a lot of miles. If it's the 6.0 diesel in your bus, pulling won't be a problem. I used to pull the same trailer I do now with an E350 with the same motor. My only concern would be brakes on the bus and brakes on the trailer. As far as the frame goes, you should be fine as long as you're loaded right.
    Phl218 and ducnut like this.
  10. ducnut

    ducnut Well-Known Member

    My 2017 Four Winds 24F was the same 5K tow rating as the OP’s unit and was built upon an E-350 chassis. And, the E-450 motorhomes are rated for the same tow capacity. The only thing that changes between them is the rear leaf springs; everything else is identical. I really think the 5K rating is just a standard number used by the industry, with very little regard for how much coach is sat atop that chassis.
  11. MotoGP69

    MotoGP69 Well-Known Member

    I think the OP’s real concern is the fact that the hitch is something like 8 feet behind the rear axle, and whether or not he is going to damage whatever framework is in that area due to the leverage created.
    gapman789 and ducnut like this.
  12. metricdevilmoto

    metricdevilmoto Just forking around

    Are the wheelbase/frame rails significantly different than my box truck? I thought they were built on the same chassis. I fully admit that I know nothing about Winnebagos. Or are you saying that the overhang is longer in the rear?
  13. ducnut

    ducnut Well-Known Member

    Yes. They’re completely different proportions.

    metricdevilmoto likes this.
  14. metricdevilmoto

    metricdevilmoto Just forking around

    Gotcha. I guess they just extend the frame rails to support the back and that's where the concern with tongue weight is coming from. I get it.
    ducnut likes this.
  15. Phl218

    Phl218 Lemme ask my wife

  16. Lawdog78

    Lawdog78 Well-Known Member

    I had one of those atv ones and it was pretty handy other than for backing up! The big ones they make for trucks I think are like $4000. They have them where you can tow a 5th wheel with an SUV (not saying whether that's a good idea or not)

    Phl218 likes this.
  17. zertrider

    zertrider Waiting for snow. Or sun.

    And whatever you do DO NOT use a weight distribution hitch on the motorhome. It will do absolutely nothing but create more stress on the frame extensions.
    Razr, Phl218 and ducnut like this.
  18. bored&stroked

    bored&stroked Disclaimer: Can't spell

    No RV shop will do it because its a liability. You'll obviously overload the thing and create a dangerous situation they helped with is how they see it.
  19. gapman789

    gapman789 Well-Known Member

    Rear frame extension strengthening would be something like this, except farther back to the rear where the 5' frame extensions are bolted to each of the main frame rails.

    rv frame.jpg
  20. zertrider

    zertrider Waiting for snow. Or sun.

    You want to strengthen from forward of thenrear axle to the rear? Don't waste your time with that much. If you feel bracing is necessary (which in your case I don't believe it is) then just add 4 orn5nft of 2x4 1/4 wall tube and brace it at the joint between the Ford frame and the extension.

    Having been a Winnebago dealership owner and service manager, I kinda know what I am talking about here.
    ducnut likes this.

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