Question on Tongue Load

[stopngo]

My 85 Elandan 31 RT 454 Chevy is rated by Manufacturer for Max 200 lbs Tongue weight and pull weight of 3500 lbs.

I Never use the 60 gallon rear gas tank behind the rear axle

I have removed the 6500 watt Onan Gen 

I do not carry more than 1/4 tank Water on the road

The above removed items eliminate close to 1,000 lbs  of cantilever behind the axle.

Question........Surely I should be able to increase not only the tongue weight but also the Pull weight?? Your comments??

[Rickf1985]

The problem is the frame extension. Look at the extension weld on the drivers side and then look at the weird extension arrangement on the passenger side. You will notice that the frame rail does NOT go through the right rear compartment! You do not want to be putting a lot of tongue weight on there. Every time you hit a dip or bump in the road the shock load on the heavy tongue multiplies exponentially. I am talking upwards of a thousand pounds for a 200 pound tongue weight. Now think what happens with a 400 lb. tongue weight! Next think you know the rear cap is separating and your doors and cabinets do not work.

[TerryH]

My 85 Elandan 31 RT 454 Chevy is rated by Manufacturer for Max 200 lbs Tongue weight and pull weight of 3500 lbs.

I Never use the 60 gallon rear gas tank behind the rear axle

I have removed the 6500 watt Onan Gen 

I do not carry more than 1/4 tank Water on the road

The above removed items eliminate close to 1,000 lbs  of cantilever behind the axle.

Question........Surely I should be able to increase not only the tongue weight but also the Pull weight?? Your comments??

In all honesty you have decreased the weight behind the rear axle. To a point and to a given situation. You have not decreased or increased the allowable ratio of allowed and acceptable tongue weight or towing weight.
What you may have done (which is good)  is increase the "possible weight" that your rear chassis may accept.
As to towing capacity and limits, strongly suggest you check further.
Cantilever action/addition/incurred problems must be considered.
Frame of your unit,particularly behind the rear axle, is only that - a frame.

[eXodus]

stopngo
how long is your wheelbase ? How long is the frame extension? Which tires do you got ? What are you Axle capacities ? What is your axle weight ?


I had a p30 29ft which had 2ft frame extension which was rated lower tongue, and 5000lbs pulling. The former owner put on a 750/7500 hitch and I did reeinforce the Frame extension with a couple of additional welds.


So I could tow 5500lbs trailer with 400-500lbs tongue, which worked fine.

They may only put on a small hitch because it was just laying around. It does not necessary mean that you can not tow. But you have to check, and doublecheck

[eXodus]

In all honesty you have decreased the weight behind the rear axle. To a point and to a given situation. You have not decreased or increased the allowable ratio of allowed and acceptable tongue weight or towing weight.
What you may have done (which is good)  is increase the "possible weight" that your rear chassis may accept.
As to towing capacity and limits, strongly suggest you check further.
Cantilever action/addition/incurred problems must be considered.
Frame of your unit,particularly behind the rear axle, is only that - a frame.

Yeah that is not completely right. The towing weight is determined by the weakest link the in the chain. If they only put on a 200/3500 hitch they rate it like that.  If the would put on a Class 1 hitch it would be maybe rated 100/1500.
So the frame can maybe tow more, you have to change the hitch probably.


Most people think that GCWR - GVWR = Tow Rating. (because it's easy and safer)  It is actually GCWR - Vehicle Weight = Towing Capacity
This says nothing about the Tongue !!! Only braking and pulling capacity.


Examples: If you got a Motorhome that has a GVWR of 15000lbs, and a GCWR of 19000lbs you have at least 4000lbs of towing.
Yet if your MH is fully loaded only 12000lbs then you can tow legal 7000lbs.


But you have to check the frame extensions ! Your main frame is rated for that tow, not the poor craftsmanship some MH have under there

[stopngo]

Thanks Y'all........Will have a closer look.

May have more questions yet. But yeah.......I can see why removing weight from behind the axle has no effect on the up and down action by the tongue weight onto the frame extension.

Lets see now....? Has anybody ever seen a tow Dolly being used with a Boat Trailer?? Hmmm.

Rick 85   

I am talking upwards of a thousand pounds for a 200 pound tongue weight.

Is that with full consideration given to the fact that this force is on the upper suspension and cushioned by the springs??

Also........Would an Equalizer hitch help at all?

[eXodus]

A Equalizer hitch should help a lot. Yet, if your hitch and Frame is not rated for equalizing I would not dare putting one on.





The equalizing hitch is forcing up the rear of the frame, which is good thing, but in certain moments, like driving over a sidewalk, the hitch is suddenly carrying a part of the weight of the coach. I'm pretty sure that's ok for a Factory frame, but a MH extensions was only designed to tow a car on four wheels with no up-force at all.

[Rickf1985]

Thanks Y'all........Will have a closer look.

May have more questions yet. But yeah.......I can see why removing weight from behind the axle has no effect on the up and down action by the tongue weight onto the frame extension.

Lets see now....? Has anybody ever seen a tow Dolly being used with a Boat Trailer?? Hmmm.

Rick 85    Is that with full consideration given to the fact that this force is on the upper suspension and cushioned by the springs??

Also........Would an Equalizer hitch help at all?

Ask and ye shall recieve. Is this what you were looking for?  http://www.trailertoad.com/

[stopngo]

if your hitch and Frame is not rated for equalizing

Ill check with the Hitch Shop.....maybe they know. Or how do I find out.

Ask and ye shall recieve.

Thanks I guess as long as I don't have to back up....or can I ??

[stopngo]

 ........Tongue Weight problem solved........All I need to do is move the adjustable axle on the Boat Trailer (Duuhhhh)Right now if I groan loud enough I can actually lift the tongue by hand for about 2 seconds so it must be over 200. Moving the axle should do it.

[Rickf1985]

If this is a single axle boat trailer and you bring the axle to far forward you are going to have serious sway issues. It could start to sway to the point of losing control so be very careful of trailer weight distribution. At least ten percent of the total weight should be on the tongue. I know that is not what you want to hear but with a single axle trailer you have to be careful. If it is a tandem you have a little more leeway but they will still sway, they will just not tend to start whipping.

[stopngo]

I hear you loud and clear. The boat I think is close to 2000 lbs (will confirm ) and if I am close there I should be able to get my 10% tongue weight (200) without exceeding the specs. The tongue weight at the moment is 270 lbs. The axle is far toward the back. and I don't think I will need to move it much at all to bring it to 200.


And thanks to Exodus as well for the input

[TerryH]

I just posted this on a different topic, but may help you.
Or you could consider me a goof.
Hope it helps.

The length of the lever(extension) and how it is fastened to the fulcrum (frame) is your major consideration. Lever length exponentially increases the downward force against the fulcrum (frame) and upward force against the lever to fulcrum connection.
100 lbs. at 4' beyond the frame connection exerts approx. 600 lbs. of force (downward and upward, but both are against the connection). Increase the 4' to 8' at 100 lbs. the force increases exponentially.
If you would like the formula I can send it to you.
Consider raising the rear of your RV using a rock at the rear and a 6' log - 2' from the rock under your unit and 4' for you to push down on.
Good luck.
Trade the log for one 20', same 2' under your unit. One hand to raise.
Downward and upward force on your frame from the weight at the ball of your hitch is similar.
Hope this helps, don't want you ending up with your towed item being left behind.
Terry

[stopngo]

Thank you and no I do not consider you a goof. And yes I am always interested in formulas and please don't hesitate to post.

Provided my boat is 2000 or under and I end up with 10% tongue weight (200) My guess would be that all the other concerns regarding swaying would automatically be taken care of. I do understand that say the boat is 3000 and in order to achieve a tongue weight of 200 I would have to move the axle further forward that that would be asking for trouble resulting in tail waggingfor lack of better terms.

All the above said however my guess would be that Winnebago conceivably used the formula you mention ie  100 lbs at 4 ft=600.......200 at 4 ft=1200.

I am only going by logic here but if I am within the specs is there not a safety margin built in there somewhere? Seems to me that Winnebago would stay away from the absolute maximum in their own interest......No?

[Rickf1985]

Boats are sort of unique when it comes to balancing your load. A lot of trailers have a fixed axle so what you have is what you have. Another thing to think about with most smaller boats is that most of the weight is in the back of the boat, especially outboards. As you hit bumps in the road the whole trailer drops but the heavier rear end will dip due to the heavier weight transfer. Therefore you do not want the front too light or when the rear dips it will use the axle as a fulcrum and actually lift up on the front. This is not something you generally run into with a car trailer or cargo. The other thing is to test drive it before your trip, on the highway in similar conditions as on your trip to be sure how it is going to handle. Better to find out if you have a problem now that after you leave. Just saying that because there is 10% of the weight in the hitch does not automatically mean it will not sway. Another thing to remember is that you have a large overhang, I am assuming you are 31 plus feet. As the front of the vehicle goes one way the back goes the opposite way pivoting on the rear axle. This in turn moves the front of the hitch to the side instead of directly pulling behind and will cause it to want to track off to the side for an instant before it recovers. This is all stuff you will get used to as you tow the boat but I wanted to make you aware that it is different than towing behind the pickup.

[stopngo]

Points well taken. My boat is a Cuddy with a high with a high windshield and extra Fiber Glass up front and is actually front heavy on my guess. But I hear what you are saying and will check it out closely.

You are right about a long overhang behind the RV Axle. I have hauled other lighter trailers and always send the wife to the back to watch the trailer through the back window to make sure it is tracking straight behind with no weaving whatsoever.