TOWING

[6V92TA]

I picked up my new to me stacker trailer in Grand Jct. last week. 3 axle 21000 gvw. I think it weighs about 6600 empty. So all in we may be 13000. The hitch weight is under 500Lb. I have an MCI with the hitch welded to the cradle. I put some 2" flat on edge the length to the cradle, as a stiffener. Anyone else pull this kind of weight behind an MCI?
Should I worry about the trans or diff?

What do the Wanderlodge use for hitch mounting?

Thanks for now, Mark

[Jon]

I don't know about MCI, but a reinforced engine cradle is required on Prevost coaches and those limits are 1500 pounds hitch weight, 20,000 tow weight.

Exceeding the weight limits does serious damage to the coach structure on a Prevost, and even adding a motorcycle lift and carrying a heavy bike has resulted in frame damage.

[Brian Evans]

Short answer - I have never heard of anyone towing that kind of weight behind an old school MC8/9 MCI.  I towed 8,000 lbs with my MC-5C and thought I was dancing on the edge.  I used a substantial weight distribution hitch system to reduce torsional loads and tongue weight on the hitch, they really do work.  Do you really think your tongue weight will be 500 lbs with a 13,000 lb trailer, or am I reading you wrong?  No worries about the transmission or the differential, your worries are purely dropping the engine on the ground behind you.  The hitch is almost meaningless, the issue is the engine cradle and frame behind the rear axle bay.  It is widely thought to not be strong enough for large extra loads.  Older MCI's tend to crack the frame at the top of the engine compartment where it drops down from the floor over the rear axle bay, and crack the cradle as it comes out to support the engine.  What MCI do you have?


Brian

[Uncle Augie]

Watching this as I am intending on either toad or trailer, and would rather a trailer

[Brian Evans]

GM's have a completely different and more serious issue - they don't have a frame that extends past the engine at all, their engine cradle bolts to the frame at the front of the engine, four or five feet from where a hitch needs support.  People have built hitches for GM buses, but I don't recall one designed for a 10K GVWR trailer.  The only bus really designed for a trailer hitch is the Prevost, from what I have read.  It's the only one that has a factory designed and rated option for a decent load hitch.

[6V92TA]

 We have an MC8. I swapped out the 8v71 for a 6V92. While the engine was out I reinforced the cradle while engine was out. Still not an extremely sturdy frame.

The problem I see with the equalizer hitch is the torque it puts on the cradle itself. Maybe not a problem at all with a 3 axle trailer. My tandem trailer has much more hitch weight than this triple mostly due to axle placement. The direct straight back pull of the heavier trailer is my concern.

I can, at least to a certain extent, the hitch weight by the placement of the load, realizing that hitch weight increases stability. I am only guessing at the 500 lb. with trailer empty but I can move the trailer around easily with a floor jack.

I asked here to see what others with MCI type busses are doing. Thanks for replies. Mark

As an added I have a friend with a Wanderlodge that has a 28' tandem trailer that weighs 10,00# loaded with probably 1500# hitch weight. Do these units have a more robust rear framework or is he too playing with fire??
.

[luvrbus]

Your friend is fine with his Blue Bird they use a raised rail frame from the front to the rear like a truck. A Newell will carry a load also you need to be careful with designing a hitch for a MCI I have seen factory hitches on MCI's before they did not pull from the engine cradle but from forward of the cradle tied into the suspension frame   

[RJ Long]

Mark -

It's not the static load on the hitch that's the problem, it's the instantaneous loads induced by the constant pounding of the tongue against the hitch ball being transmitted into the coach's structure.

IMHO, this tool is probably THE best answer to the problem:

www.trailertoad.com

At roughly $3500 for the HD model, it's cheap insurance compared to repairing a fractured frame.

FWIW & HTH. . .

 

[6V92TA]

I understand the intermittent load principal. The trailer remains somewhat static as the 3 axles keep things rather flat. Most torque comes from the motion of the bus, especially the front. As the rear hitch rises it comes into resistance from the trailer, and that force is increased by the 3rd axle keeping the trailer level.

I looked at the trailer toad awhile ago. Called over and asked some questions.I wasn't impressed by the 'rah rah' answers they gave. Basically said I was pretty dumb for asking. I think an air ride tongue would do the same thing without the 'contraption' but without seeing their system other than in tiny pics its hard to be certain. If someone here has the trailer toad  system I'd like to hear from you.

The hitch on our 8 is bolted to the stiffened cradle, and has 2x2 stainless tubing attached to the outer bus body, in 4 places. It does not attach to the suspension framework, however this may be an option. This would fix the 'pull' side of the situation, but really not address the up/down/flex side, which is prob. most important.

I pulled the trailer 1200 miles empty with no visible issues, but think it can stay home till I get this figured out. All ideas/opinions welcomed. Mark

[Jon]

This is clearly a risk versus reward situation.

The problem with overstressing the coach frame and engine cradle is most of the damage is not visible until it is too late.

It must be really important to have such a trailer to be willing to assume the risk.

[RJ Long]

If someone here has the trailer toad  system I'd like to hear from you.

Mark -

I don't have a TrailerToad, but my friend Ed Vanlandingham does.  Here are two videos I took of it when they were leaving the BCI rally in Thayne, WY a couple weeks ago.

https://www.youtube.com/watch?v=rPCGwg87u-Q

https://www.youtube.com/watch?v=SOjfQv3mMFM

FWIW & HTH. . .

 

[6V92TA]

Thanks for the links.

We wanted to attend the Thayne Rally but were occupied with fires at Cranbrook. We went to CO. a week later. Missed a chance to see the Toad in person.

Thanks again, Mark

[Brian Evans]

The way I use my equalizer hitch is to balance the torque created by the tongue weight that is twisting the ball mount downward with a fairly equal upward torque.  I don't adjust it to try to shift weight forward in the normal "equalizing" manner, just to remove the downward torque and leave the hitch in a fairly balanced mode.  I think that comparing an unloaded triple axle trailer's tongue weight to what it might be loaded might be a bit misleading, certainly when designing the load-out for such a trailer I would look for at least 10% of the gross weight on the tongue, so in your case 1300 lbs.

In terms of what other MCI owners do, I use one of these hitches:  http://www.busrvparts.com/Towing%20Hitches.htm

In terms of your specific issues, I think it's possible to design the hitch to take the load, but you need to factor in not only tongue weight but also pulling force.  Will the drag of a 13,000 lb trailer pull the cradle off the frame?  I have no idea, but I really don't think it's design contemplates that force.  Is the drag of a 13,000 lb triple axle trailer that much greater than the drag of my trailer, 8,000 lbs loaded, double axle?  Probably yes, I suspect it scales up linearly.  I think that MCI strengthened the MC-8's throughout their life cycle, I think the MC-9's (and my 1980 MC-5C may have more in common with MC-9's than earlier MC-8's) had strengthened rear subframes to accommodate heavier engines.   One thing in your favor is the 6V-92 is around 275 lbs lighter than the 8V-71 the bus came with.

I think the summary is that you will be in somewhat uncharted territory, collectively we don't seem to have anyone who towed as heavy as you with an MCI and we don't know what your hitch design is engineered to do.  I do know that when I mention how I tow with my bus, I get told that the rear subframe will crack and the engine will fall out.  Hasn't happened yet, but that proves nothing but that it hasn't happened yet... 

Brian

[RJ Long]

In terms of what other MCI owners do, I use one of these hitches:  http://www.busrvparts.com/Towing%20Hitches.htm

Brian -

If you actually got your hitch from that website, you're darned lucky.

It's owned by that notorious scammer Sam Walker, who's bilked hundreds of busnuts out of their hard-earned money.  A quick Google search for him turns up how he ended up with three hots and a cot, altho I think he's out now.

OTOH, apparently recently another busnut went buy his building, and the place is being renovated with no sign of any buses and/or parts anywhere.

FWIW & HTH. . .

 

[6V92TA]

I am pretty sure that is where my hitch came from as well, or someone copied that design and modified it to attach to the cradle in 2 places as well as the bumper mounts. Had ours off when swapping out the engine. Bolts came out easily and went back in same.
 

Previous owner had a 30' enclosed car hauler that he towed to AZ and FL with antiques/hot rods inside. This is the reason I didn't think much about towing with the bus. Was in kind of a uninformed bliss.

I talked to Sam Walker last spring about some parts he had advertised. We couldn't come to a deal. He mentioned his bldg needed major repairs and he was probably moving out. I actually knew his history. Smooth dude.