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Old 11-21-2016, 01:44 AM   #1
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Trailer hitch capacity for RE bus

So my thoughts have turned to trailer hitches that will work with a rear engine bus..... given the way a rear engine bus is built I know it will reduce the towing capacity since the weight of the engine and transmission is on the back of the bus rather than the front.... I'm thinking that a Class 3 hitch should be sufficient to pull one of those tandem tow dollies that will carry both a car and a motorcycle. Something like this....



Not sure the weight of the car but the motorcycle is around 550 lbs. Most of the weight of the car will rest squarely on the dolly axle since that's where the pivot point is, so the tongue weight from the car will be negligible.... the motorcycle is where the bulk of the tongue weight will come from, and I want to make sure I don't overload the hitch or the rear sub-frame that the engine is mounted onto. Not sure I could mount a hitch to the main frame and give it enough support at the rear of the bus to carry the weight. Has anyone successfully pulled this off?
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Old 11-21-2016, 08:07 AM   #2
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If you mounted the hitch farther forward on the frame (under the bus), and extended the tongue on the trailer, that would help you in two ways. First, the longer tongue would put more of the motorcycle's weight on the trailer axle and less on the tongue. Second, it would put the hitch closer to the rear axle and would take less weight off the bus's front axle.

Granted, it would be a PITA to crawl under the bus to connect the hitch, but if it were the kind of situation where you'd never be unhooking the trailer, it might be worth it.
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Old 11-21-2016, 10:20 AM   #3
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Originally Posted by Rameses View Post
If you mounted the hitch farther forward on the frame (under the bus), and extended the tongue on the trailer, that would help you in two ways. First, the longer tongue would put more of the motorcycle's weight on the trailer axle and less on the tongue. Second, it would put the hitch closer to the rear axle and would take less weight off the bus's front axle.

Granted, it would be a PITA to crawl under the bus to connect the hitch, but if it were the kind of situation where you'd never be unhooking the trailer, it might be worth it.
That might work, but won't you severely limit the approach angle of the bus before the extended trailer tongue hits the bus?
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Old 11-21-2016, 11:45 AM   #4
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That might work, but won't you severely limit the approach angle of the bus before the extended trailer tongue hits the bus?
Yeah, that's definitely something to look at when deciding on the placement of the hitch. The closer you get to the back axle with it, the lower you can hang it without worrying about it catching on things. The lower it is, the more room you'll have for vertical deflection of the trailer tongue.

And I could see the possibility of the first thing the tongue hits being the oil pan. It would certainly be worth mocking up a 2x4 with the end mounted where the hitch is planned to go, and move the board around as if it were the tongue and see how much clearance you have, and what it'll hit.
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Old 11-21-2016, 12:59 PM   #5
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The end of the bus frame is forward of the engine but the trans will likely be in the way, plus a minimum of 24 inch drop from frame to be able to clear the engine underneath. I have yet to get out there and take any measurements... the simplest solution obviously would be just to mount the hitch right at the rear bumper in the sub-frame but there's already enough weight in there, don't want to add another 500 lbs to it. If I thought it would hold up and not add too much weight I could see welding additional hardware to the extended receiver tube and fastening it to the subframe at multiple points, my thought is that this would spread the load out some so it's not all hanging off the extreme back end of it.

I'm wondering if a weight distribution system would be a viable option in this scenario....
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Old 11-21-2016, 01:21 PM   #6
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Originally Posted by AlleyCat67 View Post

I'm wondering if a weight distribution system would be a viable option in this scenario....
That's definitely a viable solution also. I remember once seeing a picture of an older front wheel drive car (I think it was an Eldorado) with a trailer hooked up to it. It had a weight distributing hitch that was cranked up so high they had the back wheels taken off of the car and were driving it on just the front axle of the car and the trailer axle.

Realistically, with only 500 lbs of tongue weight, and the back axle so far back in a rear engine bus, you won't have to worry about the front end getting light even with a traditional hitch mounted all the way to the rear. Especially after water tanks, a generator, batteries, etc are added in front of the rear axle.
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Old 11-21-2016, 01:26 PM   #7
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It's not the front end getting light that I'm worried about.... I'm worried about overloading that subframe and having it fall off as I'm going down the road. Granted I don't think that would happen, at least not very likely, but would prefer not to tempt fate.
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Old 11-21-2016, 01:43 PM   #8
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Ahhh, gotcha.

Sorry, I totally misunderstood the nature of your concern.
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Old 11-21-2016, 02:02 PM   #9
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Hey, no worries. In a front engine I wouldn't hesitate to put that hitch on the back end and tow like crazy.... but with the engine in the rear that adds a whole level of complexity to the equation. If it was strictly load balancing then yes my full fresh water tank would more than offset the tongue weight of the loaded trailer.

If it were just pulling a car on a dolly there again it wouldn't be a big deal because a car puts most of the weight on the trailer axle so the tongue weight of the dolly would be negligible at best (50-100 lbs). But adding nearly 600 lbs of motorcycle changes things... #1 it rides forward of the car so at least some of the bike weight is on the tongue (and the farther forward it sits, the more tongue weight there is). A longer tongue on the dolly would offset that to a degree but you can only stretch it so far.

Like someone mentioned earlier maybe mounting the hitch farther forward and sliding underneath to hook up, while a RPITA, would be a viable option if the dolly tongue is long enough for everything to clear the bus body and low enough to clear the oil pan and any other component hanging down at that level.... that would at least lower the stresses at the subframe attachment point to the main frame.

As I said, I still have to get under there and get some measurements to see what I have to work with...
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Old 11-21-2016, 02:29 PM   #10
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I think with any hitch running under the engine, when your front axle goes over a speed bump or driveway with not much height/incline, your going to be dragging your .............behind.
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