Adding receiver hitch to popup camper for motorcycle hauling

[nakman]

Saying no to the Jayco.. just can't do it. Particularly the 10y, as with the 8' box it's just too small. Plus, that's a lot of money to drop on another camper, and once I had the bikes unloaded I'd just be bummed I had a smaller camper. There are others on the market as well, but all pushing the $10k mark, which is way more than I want to spend.

But here's an E-2: http://denver.craigslist.org/rvs/2960228907.html

Here's a gazunga huge Starcraft: http://denver.craigslist.org/rvs/2988939921.html

A Forest River http://denver.craigslist.org/rvs/2994176538.html

another ridiculously huge one http://denver.craigslist.org/rvs/3014262399.html

If money, space, and practicality weren't constraints, I'd like to go this route though for $15k. http://denver.craigslist.org/rvd/2988471040.html this could be the next phase, presuming the whole family is into bikes in 4-5 years.


For now, I'm going to stick with what we got, and work on getting a new axle with 5x150mm hubs and M14 studs. Then build up a new frame & do a box swap.. plan 1 above.

 

[60wag]

On all of those models it looks like the axle is in the middle of the box and the hitch end of the frame is extended for the cargo platform. That looks to make for a lot of tongue weight. Am I missing something? I would expect the axle to move forward as the trailer gets longer.

 

[Red_Chili]

It still has to tow right unladen, though. Nak, you may be in the market for airbags.

 

[nakman]

Help me with the math here... What multiplier would I use against bike weights, to calculate that bike's change in tongue weight? What's the TWM (tongue weight multiple?). I realize the bike's position on the tongue is also a factor, so presuming I could potentially do 4 bikes that's a separate variable for each; TWMa, TWMb, TWMc, and TWMd.

Bike*TWM = change in tongue weight, resulting from the bike.

So what I need to do is predetermine what I want my tongue weight to be unloaded (or with 1 propane and 1 battery), then estimate my TWM variables for each bike. Then I can work through scenarios loading from 1 to 4 bikes and calculate their net effect on tongue weight. Seems simple enough, right?

 

[nakman]

A, B, C, and D are in order of how I'd load them. Not sure if I'd get to 4, but this exercise will help answer if that's even attainable. Also I am guessing 150 as my starting tongue weight, assuming 1 propane tank and 1 battery on the tongue (which could change, if necessary) I'm going to start with the following guesses:

TWMa = .61
TWMb = .72
TWMc = -.35
TWMd = .80

I could also estimate some bike weight variables..

Bike A = 240 my 250 XCF-w
Bike B = 110 Gavin's 50
Bike C = 185 Gavin's 80, when Violet gets his 50
Bike D = 250 My 450, when MIchele gets my 250

Putting all of that into a calculator, it seems very possible to stay within my receiver hitch's limit of 650 pounds tongue weight. My current slide-in ball thing says 500 pounds though, that's a better target anyway. Here's a calculator to see how this works out.

 

[nakman]

So far my first thought is move the 50 pound battery to under the bench seat in the camper, behind the axle. Or, under the trailer somehow (Red Chili style!). As I add bikes, the tongue starts to look pretty heavy and I'm guessing that 100 pounds is still enough weight to safely pull it empty?

 

[60wag]

Your TWM should be based on the distance from the axle. A bike over the axle will not affect tongue weight. As the bike moves away from the axle it creates a moment about the axle which can be resolved into a force at the hitch.

 

[nakman]

Your TWM should be based on the distance from the axle. A bike over the axle will not affect tongue weight. As the bike moves away from the axle it creates a moment about the axle which can be resolved into a force at the hitch.

Agreed, so do you have a way to more accurately calculate that? Or better guesses than

TWMa = .61
TWMb = .72
TWMc = -.35
TWMd = .80

??

 

[60wag]

If you are carrying two bikes, this setup might be the most simple with the existing trailer:

http://denver.craigslist.org/mcd/2990474425.html

Maybe adding just the 50 or 80cc bikes to the trailer would be much easier due to their low weights?

 

[Jacket]

^That's pretty cool, and a good price. I might pick one up.

 

[Red_Chili]

I can't imagine the tongue weight would work out well with towing too! Maybe with a load equalizing hitch arrangement, dunno. And of course ANY play WHATSOEVER will result in some hair-raising sway.

DAMHIK...

Pretty cool by itself though. I wouldn't put two bikes on it...

 

[nakman]

I agree Bill, I could see doing 1 bike on there, then one on the trailer, but 2 bikes trailer is well in excess of my 500 pound load limit.

Plus, it looks really busy back there- any sharp turn and you'd crush the bikes with the camper.. as it is already I have to watch one of my tail lights when backing up, or it'll hit a tie down bar for the bike mount on the trailer. One of my motives for just modding the camper is getting the bikes back and out of harm's way when towing, plus allowing for access to the rear hatch even when it's all hooked up.

 

[Jacket]

I was thinking one adult bike and one pint size bike (for me).

 

[corsair23]

How about using ^that^ on the back of the popup, assuming you can add the receiver hitch to the popup in a way that is structurally safe?

I agree that using one of these right off the back of the rig would add more tongue weight than something further back toward the axle of the popup.

What tongue weight is typical for you now and how does the popup tow? If it tows great now then I would do what you can to keep the tongue weight as close to what it is today. Heck, you could do some tongue weight tests before you get too far down the road and see what is acceptable to you.

I know for me with the 80, the tongue weight I end up with when I have just a full propane tank on the front of the trailer is about perfect. A little less than perfect with a battery in the battery box. With a battery, and two full propane tanks up front like I had for the trip to Area BFE for CM10, the popup towed like poo. On the trip home with 1 empty and a 1/2 full propane tank and the batteries moved inside closer to being over the axle it towed great again.

I guess what I'm saying is that even though per Toyota you can have say a max of 500lbs of tongue weight doesn't mean you are going to be pleased with how the camper tows...find the sweet spot and try to stay as close to that as possible.

Here is a fun read (start at page 12) --> http://www.faa.gov/library/manuals/aircraft/media/faa-h-8083-1a.pdf

If you could find some of the inputs needed then you could use the same formulas used to determine CG on aircraft for your popup

 

[60wag]

My old pop up had a tounge weight around 100lbs and towed beautifully. What I liked about it was that I could hitch and unhitch the thing by myself. I had only to get the ball close to the trailer socket and I could pop the thing in place. Once the tongue weight exceeds 250lbs, it becomes a bit more difficult to get things lined up - especially if you are on uneven ground. I thought that putting some of the moto weight on the truck (rear carrier) and less on the trailer would keep the trailer in a manageable range. Also as the trailer gets longer, backing it up to manuever gets harder.

Also, it might be worth investigating a class 4 receiver to increase the weight limit.

 

[nakman]

Well I think it's fair to say I'll most likely transition from a Class III receiver to a completely unrated, untested, you'll die if you even use it, integrated receiver hitch- like you have.

"they" say that ideal tongue weight is 9-15% the total trailer weight. I think I will be in the 2200-2800 pound range depending on load and quantity of bikes. So while attractive, I think 100 pounds is going to be on the light side..

 

[corsair23]

Also as the trailer gets longer, backing it up to manuever gets harder.

I'm the opposite...

IMO longer = easier

Shorty trailers are squirrely IMO...Although you need more room to manuever the longer trailers so there is a tradeoff

 

[MountainGoat]

I'm the opposite...

IMO longer = easier

Shorty trailers are squirrely IMO...Although you need more room to manuever the longer trailers so there is a tradeoff

Ditto. Give me a 45 foot flatbed tractor trailer rig any day over those twitchy little stubby adventure trailers. You can drive backwards for days no sweat.

 

[Red_Chili]

Long trailer short truck = happiness.

Short trailer long truck = need to become very adept at planning.

Of course... I now have a short trailer and long truck.

 

[Beater]

seriously dude. go write the flipping check and be done with this nonsense.

http://www.campingworld.com/rvsales/travel-trailer-toyhauler/7/

every time I have tried to make the best of both worlds, I end up with the mediocre of one. just food for thought.

j