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Author Topic: Extending the frame rails out the back...  (Read 2971 times)

1joester2

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Extending the frame rails out the back...
« on: September 13, 2009, 01:52:13 AM »
I've been considering getting a couple scooters to tote around with the RV. I would need the means to carry them, so I was thinking that I could extend the frame rails out the back maybe 3 or 4 feet to make a deck to hold the scooters and whatever else I put there. This would basically move the rear bumper out and the hitch with it.

The only cons I can really think of is hitch height fluctuations and rear bumper swing (if that's the term for having the rear bumper swing out farther when turning a tight turn) while maneuvering.

Does anyone know of someone who has done such a project or am I nuts? I was thinking I could probably enclose it too (eventually).
Common sense to many of us is, unfortunately, the higher education some strive to attain.

Joe and Carol
2001 Coachmen 220RK W/GM 7.4 Vortec

Tom

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Re: Extending the frame rails out the back...
« Reply #1 on: September 13, 2009, 03:59:17 AM »
I believe a couple of folks here have done something similar to tote cargo, not necessarily scooters. A search may turn up something. In our case, we tow a Suburban, and I made a simple rack to mount the scooters inside.
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Gary RV_Wizard

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Re: Extending the frame rails out the back...
« Reply #2 on: September 13, 2009, 08:50:20 AM »
Rear bumper swing would be a small problem. So would tail drag when entering/leaving  the highway up a slight incline (very common).  I would also be concerned about lifting weight off the front axle and subsequent steering problems.  All those things can be dealt with if you are cautious.

Some front engine coaches already have an extension on the back, under the body. They use a short wheel base chassis and add to it. This existing extension may not be all that strong - there have been reports of people bending it with the use of receiver-mounted cargo carriers or even towing with a drop hitch.  Again, this can be overcome with a suitable design that beefs everything up.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

1joester2

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Re: Extending the frame rails out the back...
« Reply #3 on: September 13, 2009, 09:32:23 AM »
I'm thinking I could probably do it and get away with it since the rear overhang on mine is nowhere near what I've seen on other rigs. The frame is quite beefy on mine where the hitch is mounted.

Another consideration for room there is moving the spare tire to the front. I looked around last night online and couldn't find anything but push bars people had modified to accept the tire. I can go that route, but would rather just get a mount if available.

I like the idea of the spare up front to protect the grill and radiator. I might do that anyways and just add a second spare for our future Alaksa trip.
Common sense to many of us is, unfortunately, the higher education some strive to attain.

Joe and Carol
2001 Coachmen 220RK W/GM 7.4 Vortec

Gary RV_Wizard

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Re: Extending the frame rails out the back...
« Reply #4 on: September 13, 2009, 09:57:43 AM »
Many newer rigs do not carry a spare at all. You can throw a tire (unmounted) up on the roof if taking a long trip in sparse country, e.g. Alaska.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

1joester2

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Re: Extending the frame rails out the back...
« Reply #5 on: September 13, 2009, 10:31:52 AM »
I had considered the unmounted tire on the roof, but I would have to install something to tie it down. I have nothing but the Winegard and roof vents to tie it to and really don't likre the thought of piercing the membrane.

I'm not opposed to changing a flat on mine, in fact I've done it twice now. When I used road service on Labor day (known bad spare tire- slipped belt and exposed wear bars) , the only tire available was completely different than what I have mounted. Uniroyal Ameri-550 (load range D) VS Firestone Transforce A/T (load range E) and mixing tires doesn't seem like a good idea. That's what got me curious about stepping up a load range. Fortunately, the flat was due to a bad valve stem and I was repaired quickly.

I had considered mounting the spare under the frame extension, but the weight concerned me. maybe I could move the full spare to the front and make a storage place between the frame rails for an unmounted tire. If the frame is more than 32" wide, it might be possible and that would cut down on the weight I'm thinking of adding to the rear. 100 lbs on the front bumper would help offset. I need to calculate the effect on GVWR.
Common sense to many of us is, unfortunately, the higher education some strive to attain.

Joe and Carol
2001 Coachmen 220RK W/GM 7.4 Vortec

Alfa38User

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Re: Extending the frame rails out the back...
« Reply #6 on: September 13, 2009, 10:50:20 AM »
Looks like a lot of speculation going on since the OP has not given Make, Model, Chassis, Length, amount of present overhang of the vehicle in question nor the projected weights of the additional load etc, etc.

As was mentioned, some chassis are already stretched, some between the wheels (ie longer wheelbase), other behind the wheels, some with lighter frame members behind the wheels.   Some of these would not be good candidates for further extensions and a "couple of scooters and whatever else..." could tend to be on the heavy side. Any extension will not increase the load carrying capacity of the current machine as set by the manufacturer, but only the space available.   Offered as IMHO only!!
Stu
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John From Detroit

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Re: Extending the frame rails out the back...
« Reply #7 on: September 13, 2009, 11:06:19 AM »
If, and I STRESS IF!, your hitch has the weight carrying capacity they make hitch haulers with receiver extensions on them.  Using this kind of system you can tow your towed and no need to modify the RV itself.

On the other hand.. Wife's scooter fits INSIDE my towed.

(And My "Scooter" has 27" wheels 18 gears and 2 pedals so it fits on the antenna mount. er. Clothsline holder, er, Bicycle rack)

And if you use a Drop receiver adapter.. You can weld a 2nd receiver atop the adapter and put the hitch hauler on it.

But.. Many hitches have a 500 pound load carry limit.. and 2 scooters plus deck.. Might exceed

SO, extending the frame rails.. Depends on the rig.. On my rig this would require about 4 good size bolts.  Little more.
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1joester2

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Re: Extending the frame rails out the back...
« Reply #8 on: September 13, 2009, 11:29:52 AM »
This would be on a 2001 Coachmen Catalina Sport 220RK With a GM C3500 chassis and 7.4 Vortec.

My intent is to extend the frame and move the hitch adding probably 3 feet to the rear. I currently have 8 feet from center of the rear tires to the rear face of the bumper. I see the frame rails are far enough apart to accomodate my plans.

The only time I've ever scraped in the back was while towing with the tow dolly and the ramps were the culprit. I imagine that would be amplified with the rear extended if I do it.

The only other option would be a large enough trailer to load the car, scooters, and bikes. That would also make backing up easier than with the tow dolly. I've done it a couple times, and it isn't easy.
Common sense to many of us is, unfortunately, the higher education some strive to attain.

Joe and Carol
2001 Coachmen 220RK W/GM 7.4 Vortec

Chet18013

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Re: Extending the frame rails out the back...
« Reply #9 on: September 13, 2009, 01:47:13 PM »
Before you jump and extend the frame, look into the max GVW of your rig and what the rear axel is designed to carry. Then see this:

http://www.blueox.us/Carriers/carriercalculation.pdf

Check the weight you'll be adding. I've got a friend who added a heavy duty lift to his Country Coach for a scooter and just with the lift his rear axel was 600 pounds over weight. Remember with a rear lift, some of the weigh is transfered from the front wheels to the rear plus the weight of the rack and scooter. He wondered why the steering seemed a little funny with the scooter on the lift.

Chet18013
« Last Edit: September 13, 2009, 01:49:33 PM by Chet18013 »
Chet18013
Full time in a 45' '04 Monaco Signature
towing a 2014 Jeep Grand Cherokee diesel

Alaskansnowbirds

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Re: Extending the frame rails out the back...
« Reply #10 on: September 13, 2009, 02:41:02 PM »
Attached is a spreadsheet that will figure the added weight to the rear axle and how much weight will be removed from the front axle.

Be sure to include the weight of the scooters.
Don & Peg
Alaska/Arizona
Currently located here.
Weather at Camp Verde, AZ.

 

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