Frame Extensions on Class C rated for #7500

[RacerX10]

I wonder if anybody has, or can get, photos of the frame extensions on an Class C rated for #7500 towing ?

My 2013 Fleetwood Jamboree is just showing #5000 (the hitch class of course) but I want to see if anything is different in the frame extensions on the newer ones rated at #7500.

Thanks !

[rice_classic]

Originally Posted by RacerX10

I wonder if anybody has, or can get, photos of the frame extensions on an Class C rated for #7500 towing ?

My 2013 Fleetwood Jamboree is just showing #5000 (the hitch class of course) but I want to see if anything is different in the frame extensions on the newer ones rated at #7500.

Thanks !

I don't have photos but I have done this. I tow #7500-ish pounds with my C. I took it to a Hitch shop that does this. Reinforcement, IV hitch and 7 pin. Starting googling around your area for "Tow Hitch installation", "Hitch Shop" etc. Call around too. TorkLift Central here wanted $2600 and their competitor, Ballews, charged me just over $800 all said and done. Very happy I called around.

Secondly - get it done now as it's most likely their off seaason. Once March hits you're probably looking at long wait times or higher prices or both.

[Gimpyvet]

I too am looking at how to build a stronger sub frame for the back of my class c. I am only a 23 footer and want to put my bike on the back. So far all I see are fab shops throwing a lot of metal on the back with no engineering done.

I would think a subframe designed would be usable on multiple years just like the hitches apply to many different models. Until then I will follow this thread to see if any others have an answer.

[Mich F]

Originally Posted by Gimpyvet

I too am looking at how to build a stronger sub frame for the back of my class c. I am only a 23 footer and want to put my bike on the back. So far all I see are fab shops throwing a lot of metal on the back with no engineering done.

I would think a subframe designed would be usable on multiple years just like the hitches apply to many different models. Until then I will follow this thread to see if any others have an answer.

My previous MH was a 24' Coachmen, which came from the factory with a 3,500# rated hitch. I went to a local metal fab shop where he built a new hitch which was tied into the Ford frame in front of the frame extension.

[rice_classic]

Originally Posted by Gimpyvet

I too am looking at how to build a stronger sub frame for the back of my class c. I am only a 23 footer and want to put my bike on the back. So far all I see are fab shops throwing a lot of metal on the back with no engineering done.

I would think a subframe designed would be usable on multiple years just like the hitches apply to many different models. Until then I will follow this thread to see if any others have an answer.

Extending/reinforcing a frame is not exactly rocket science but FWIW, shops that do this often won't put their name on something that's going to fail. Welding in additional box framing or I-beam is generally all that's needed to ensure your frame extensions don't bend/snap when adding the extra lever via the hitch.

https://torkliftcentral.com/custom-f...-frame-upgrade

But on that note, find a shop local to you and ask them what they do. If you're not comfortable - call another shop.

[texkayaker]

Would all of this and adding the weight of a motorcycle not overload the rear axel?

[ThePowells]

Originally Posted by texkayaker

Would all of this and adding the weight of a motorcycle not overload the rear axel?

Very possibly. Everything added behind the rear axle will add to the rear axle, plus adding the weight of the bike and what ever mechanism to the far back will also move the center of gravity farther to the rear and can actually move weight from the front axle to the rear.

[Gimpyvet]

When we took our last trip we were 1000# light on the rear axle. Since then we have lost even more weight but the bike is only adding another 600 pounds or so. We should have plenty of weight and still ride level and smooth. I have seen many others in Southern California doing the same. My bike is just about 200 pounds heavier than theirs.

[Gordon Dewald]

Originally Posted by Gimpyvet

When we took our last trip we were 1000# light on the rear axle. Since then we have lost even more weight but the bike is only adding another 600 pounds or so. We should have plenty of weight and still ride level and smooth. I have seen many others in Southern California doing the same. My bike is just about 200 pounds heavier than theirs.

Take the weight of the bike and multiply it by the distance from the front axle to the bike and divide it by the wheelbase. Do the same with the weight of the carrier you are adding to carry the bike. Add the two numbers together and you will find how much extra weight will be on the rear axle.

[Gimpyvet]

800x22/13=1354 pounds.

Still if I were to tow a trailer I would be adding 3-500 pounds to the rear with tongue weight. Which would, using the same math, be 508-846 pounds. So the bike versus a trailer would be a difference of about 5-800 pounds inside the RV but the wife would add 2-3000 pounds of crap to the new trailer maxing out our load.

I did get a chance to crawl under the RV and look at the frame. The main frame runs 3 feet shy of the rear bumper. A poorly designed extension made of bent plate metal that does not fit well to the top of the frame makes up the difference to attach a bumper. Most of the strength comes from the hitch mount and associated brackets. Otherwise it is 3/8 plate with a 1.5 inch 90 degree fold giving it strength.

My thoughts are to remove completely the extension. It only holds up the utility bins and bumper. Add trailer C-Channel and associated sub frames for the rear components. Currently there is an 18 inch overlap and 3- 3/8 bolts holding the extension in place. There are 6 factory drilled holes not used intended for bumper and hitch installs that I could use. The 3 bolts now are poorly made with excessive size to align the subframe and holes. In other words they predrilled and had to bore out some holes because it did not fit.

Looking under a Budget truck with an extended box they had a much stronger frame extension. I believe I could increase the rating to 7500 pounds and 750 pound tongue weight easily. If I change my rack to a lighter design without cargo capacity just a rail for the bike tires I can drop it's weight to 75 pounds from 200. I think I was in overkill mode with first design. The smaller dual sport hitch lifts are made much lighter and hold 500 pounds.

If I can get the photo dump box to work I will post pictures of my undercarriage.

[tderonne]

We rented a 32' Class C Thor in Alaska this summer. It had a 8000 pound rated hitch. (Tongue weight was like 500.)

I took a couple quick pictures of the frame extension. They are attached.

I googled a bit for some better pictures, as mine were just snapshot. I haven't found anything better, so here they are.

Stock frame ends just past the back of the fuel tank as can be seen in the last image.

[Gordon Dewald]

Originally Posted by Gimpyvet

800x22/13=1354 pounds.

Still if I were to tow a trailer I would be adding 3-500 pounds to the rear with tongue weight. Which would, using the same math, be 508-846 pounds. So the bike versus a trailer would be a difference of about 5-800 pounds inside the RV but the wife would add 2-3000 pounds of crap to the new trailer maxing out our load.

I did get a chance to crawl under the RV and look at the frame. The main frame runs 3 feet shy of the rear bumper. A poorly designed extension made of bent plate metal that does not fit well to the top of the frame makes up the difference to attach a bumper. Most of the strength comes from the hitch mount and associated brackets. Otherwise it is 3/8 plate with a 1.5 inch 90 degree fold giving it strength.

My thoughts are to remove completely the extension. It only holds up the utility bins and bumper. Add trailer C-Channel and associated sub frames for the rear components. Currently there is an 18 inch overlap and 3- 3/8 bolts holding the extension in place. There are 6 factory drilled holes not used intended for bumper and hitch installs that I could use. The 3 bolts now are poorly made with excessive size to align the subframe and holes. In other words they predrilled and had to bore out some holes because it did not fit.

Looking under a Budget truck with an extended box they had a much stronger frame extension. I believe I could increase the rating to 7500 pounds and 750 pound tongue weight easily. If I change my rack to a lighter design without cargo capacity just a rail for the bike tires I can drop it's weight to 75 pounds from 200. I think I was in overkill mode with first design. The smaller dual sport hitch lifts are made much lighter and hold 500 pounds.

If I can get the photo dump box to work I will post pictures of my undercarriage.

You are correct. Attaching a trailer with a 500 tongue weight will add 800 to the rear axle weight. 300 will come off of the front axle. The manufacturer has determined through engineering or testing or something that is an acceptable weight.

You can replace anything you want to bolster the capacity but without extensive engineering you will be unable to get any legal documentation for a higher capacity.

[Gimpyvet]

tderonne that is exactly the same extensions. Bent 3/8 inch plate with welded gussets. The bad part on mine was the way it was installed. Poor spaces and sloppy bolting.

Gordon I am not looking to reclass or certify the rig. In California it is easy by going to any scale or CHP office, with an appointment of course. For me it is more about carrying safely and not having a bike hanging off the back at an angle. We travel light, if we do not include our over weight basset hounds.

Now that I have looked closer I do not like the plastic trays for rear storage either and some other minor issues. This may be a onetime work over around the frame extension. The plastic is much improved over the older wood bottoms but on mine as a retired rental some of the edges are broken or slipping off the mounts.

[Unplanned Tourist]

How about one of those swivel wheel rear carriers? Something to look at.

The ultimate single wheel trailer system.

Happy Glamping.
ps. here's a little youtube video of one on the back of a 5th wheel.

https://www.youtube.com/watch?v=WK_AvYeiMVk