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Welding on Over Built Hitch
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The old hitch is removed and a new one is bolted in it place ,,. I was told the it would be good on an xl pre 60 series detroit possibly 8v92 had a stronger frame on my old hitch tougue weight was 500 lbs on the new one it says 1000 lbs . I dont want it to be unsafe or of danger to anyone. excaliburcoachus.com
go here and look at hitches it showes them on a Prevost. http://excaliburcoachus.com/prevost_service/Hitches/index.html -
August 14, 2012
Jon,
I know that we have seen some of these carriers on motor homes. Most are installed without talking with Prevost. Most do cause you to exceed the tongue weight and distance and that’s will usually cause the hitch to develop cracks in the hitch and possibly in the frame pieces to which the motorcycle carrier is attached.
The hitch we install is for pulling purposes. It is not expected that the down weight on the hitch will be that great. Plus the weight is cantilevered out from the rear bumper and places additional stresses on the entire engine cradle as the unit goes down the road with the ups and downs of the pavement.
We have seen cracks in the hitch and the sub frame members. We do not do any repairs to the cracks due to the liability issues involved.
Another issue is the ride in the rear of the vehicle. It is usually more rough. Plus there tends to be more problems in maintaining normal road height in the rear of the vehicle.
We have always cautioned people about these hitch additions and told them we will accept no responsibility for damages done to the coach or hitch because of the bike carrier. Plus in most of these cases the owner is also pulling a car or trailer behind this bike rack addition. This stresses the engine cradle and sub frame.
As I have mentioned many time to the owners of the conversion coaches we built a shell for a motor home and gave it the ability to pull along a car or a trailer with a car in it. We are not making a truck out of it. As we are asked to be able to carry more weight we begin to move from motor home shell to commercial truck and you get the appropriate ride degradation and stiffness.
I guess we will wait and see.
William Jensen | Service Manager, Shell Division
That is a copy of an email I received yesterday. Nothing more needs to be said.
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I am the kind of guy that will push things as far as they will go, and always try to get the most out of everything. I am also NOT risk adverse. That said, this is NOT something that _I_ would do. Too little gain from too much (potential) pain.
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Aviation does that to folks. We go right up to the limit, but most of us are smart enough to know the minute we cross the line we go from “pilot” to “test pilot”.
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I asked a
similar question on this board maybe a month or so ago and had about the same
answers. Even though I want this lift, I’m able to fabricate every thing I need
and I’m very tempted. My gut feel, experience, whatever you want to call it just
says, it’s risky. You might be able to pull it off or it could cause problems, I
don’t know, that’s why I haven’t done it. I work for a vehicle manufacturer in the test
lab, I know Prevost is going to CYA on this question, but I also have to
respect their experience.
I would say
that if I were to do it I would not do it like the pictures provided in the
link. Using that method all the weight and stress is on the engine cradle, I
would move the outer receivers just under the frame rails that run down beside
the taillights or directly to the outside of the frame rails that support the
engine. Maybe that doesn’t matter all the weight and related forces are still applied to the rear of the coach.
Ken
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This debate on the motorcycle carrier has many opinions. I can’t help but think of the three words on all projects, “Risk vs reward” and this is the caution in making the alteration to the structural integrity of the bus.
Have you considered a pick-up truck, load the bike in the rear bed and all is OK. Their might be some stiffing up the rear end of the pick-up, but nowhere near the money spent on this hitch modification.
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While the focus is on the stresses imposed on the Prevost chassis Bill’s remarks about how the weight affects the coach are spot on also. I suspect the age of the coach Repoer is driving does not have ABS and after reading Bill’s remarks I got to thinking the impact of that much weight cantilevered off the rear will have on braking and handling.
If any of us want to see a dramatic change in how fast our front end will rise after it has been lowered all the way down, raise it normally and time that, then lift the tag and repeat the process and compare the times. Now imagine a substantial weight whose center of gravity is about 8 or 10 feet beyond the tag. All of a sudden a lot of weight has been transferred off the steer axle onto the drive and tag axles. That has to have a significant effect on braking and steering, especially on wet or slippery roads.
Our brake chamber sizes and brake shoe widths are sized for equal braking on all axles and the coaches have to go through rigorous testing to meet the braking standards and get certified. I would think that much weight, even if the frame did not eventually get cracks would ruin the handling and braking characteristics of a nicely balanced coach.
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Follow this link, if it works, to overbiltlifts.com . There is a 3-4 frame grainy video of their electric motorcycle lift in action. Watch the back end of the bus move as it lifts into the air.
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Hitches are designed to both tow and support suspended weight. Unless you are using a tow bar or tow dolly the rule of thumb is that a trailer’s tonque weight should be 10-15% of a trailer’s total weight. With too little tongue weight you increase the possibility that the trailer will want to fishtale. Most hitches have a tongue weight equal to or greater than their maximum tow weight. The 10% tongue weight recommendation is why hitches have a tongue weight rating equal to at least 10% of their tow weight.
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“Most hitches have a tongue weight equal to or greater than their maximum tow weight.”
Is that what you meant to say? My 97 had a 10,000 pound tow limit and 1000 pound tongue weight limit or 10%. That would be consistent with what I think you meant.
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Yes Jon that is what I meant to say.
Thanks for clariifying for other readers,
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It’s nice to know I am not the only one that lets my fingers outpace my brain. It was bad enough when my mouth was engaged before my brain.
Your post and points made were good.
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I have had mine for 3 yrs, scooter weighs about 700lbs, Been everywhere
I pull a Jeep rubicon Stock weight 4,500 lbs extras probably 5,500lbs now
The bus is showing no stress signs, It is about 73 ft long and will cruise a little over 80 and drive with one finger
The air bags adjust for the weight of the bike, Bus stays level while staying over in campgrounds for a week or two no
problem, I dont even drop the bike down,
Now with all the cautions I wouldnt dare chance it unless you were taking a Harley .)
I Love to Ride and I Love to Wheel ,
If your a Rider and a Wheeler your already a chance taker !!!
I been wathcing mine close and havent seen anything yet looking at the cradle and body,
I almost went to the 20,000 lb hitch untill I found out they had to change out the whole engine cradle,
The jeep pulls through the Bike lift so I put a drop reciver on the Bike lift so the jeep woudnt be pulling down on the lift
and during breaking it will push up on the lift slightly,
Anyway its all in what you want and how bad you want it !!
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“The bus is showing no stress signs, ”
And there is the problem. The cracks and weld failures are not readily visible until the problem reaches epic proportions.
Everyone needs to re-read the post on this thread containing Bill Jensen’s explaination of the problem. It is the post dated 8/15/2012, 12:59 PM
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Has anyone ran there bus up on a scale just to see what it weighs with fuel and water full and loaded for a mild trip,
No motorcycle rack no car or trailor.
I know what mine weighs and its suprising ??
What is yours weight ???
No fibbing !!
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