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weight&balance, bumper pull


stinky

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I'm searching for a toy hauler and intend to pull with a Nissan Titan.

After looking at various spec sheets I am a bit confused at how to calculate the actual hitch weight.

I understand why the hitch weight is designed to be high but once weight is added in the garage hitch weight&balance will shift, how can that be calculated?

Most medium size bumper pull haulers come in with hitch weights near my capicity or well over and none give any guidance concerning loaded weight&balance.

My top end is 940 but if I hook-up a hauler that has only a 825 hitch weight

and load it with 500lb in the garage (motorcycle) and have 1/2 full tanks in the hauler, what happens to the hitch weight? I do not really like the 825 to start with and I certainly do not want to overload my truck. Max gross weight is not a real concern, that is easy to deal with.

The 825 is just a number I estimated after looking at several spec sheets.

 

Thanks,

I'm a new guy from N.Ca. just getting started.

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Yes but how do you get the actual weight figure?

IE.

If I have brand X hauler with a hitch weight of 825 empty & dry. What happens to

the hitch weight if I put 600lbs in the garage? Yes the hitch weight goes down but how far, by what percentage of dry weight?

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For weight added behind the axles, it's the classic teeter totter ... the ratio of each distance to the fulcrum (the midpoint of the axles) determines the balance.

 

If the load is 10 ft. behind the fulcrum and the hitch is 20 ft. ahead of it, you have a 1:2 ratio.

 

Adding 100 lbs 10 ft. behind the fulcrum will balance 50 lbs. 20 ft. ahead of the fulcrum, i.e. it will take 50 lbs. off of the hitch. 150 lbs. will be added to the axle weight (100 lbs from the load + 50 lbs removed from the hitch weight).

 

For weight added ahead of the axles, the frame acts like a bridge. If the load is centered between the hitch and the axles, 50% of the weight will be carried by each one.

 

Move the load closer to the hitch or closer to the axles and the weight on each point is again determined by the ratio of the distances from the load to each end of the bridge.

 

I'm sure someone else will come up with the mathematical formula for all of this ... it's not my strong suit.

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Sometimes the toy haulers are set up with a heavy tongue weight and adding the toys reduces it. If the entire garage is behind the axles then adding a toy will likely reduce the tongue weight depending on how far forward you put the toy.

 

If the toy hauler you are considering is set up this way then you might be able to get a good feeling for where things lie by getting a Shurline scale and checking the weight of a unit at the dealer. Be aware that you will quickly add a fair amount of weight to the front with batteries, propane and additional "sufff" if there is significant storage in front of the axles. You might be able to balance this out with your MC if you intended to haul it every time you use the trailer.

 

Another very ballpark approach is to get the GVWR of the trailer and multiple by 0.15 and see if your tow vehicle can support that tongue weight. It may be possible to use a trailer where GVWR*.015 is greater than the max tongue weight but you'll need to be more careful with loading to keep the actual tongue weight within spec.

 

 

Don't forget that the tongue weight the trailer can handle is often reduced if there are a lot of passengers or "stuff" in the bed of the pickup.

 

I would not trust the published tongue weight. My non toy hauler trailer had a published tongue weight of around 750 lb. With propane, batteries, fresh water and a few things in the front storage we are at 1100/1200 lbs.

 

 

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I went looking to see if I could find some weight and balance software, there is some aimed at aircraft load-masters but I didn't see any free stuff or offerings for private pilots. Maybe someone has a spreadsheet or something similar that could help you with planning your balance but I didn't see it in my brief look.

 

Paper, scale and measuring tape will do the job so you can get to an answer with a bit of work.

 

Do you have an equalizing hitch? They won't increase your allowable tongue weight but they will let the truck ride closer to level and take some weight off the rear axle.

 

On your truck look at all the weights, combined, tongue and axles to make suer you are safe on each.

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  • 2 months later...

Thanks for the help.

I have a toad & trailer combined spreadsheet that I use to adjust the loading of our Freightliner and toy hauler and the spreadsheet works well for me and I have confirmed it's functions many times on actual scales.

 

The catch when calculating weight & Balance of any combination is the classic math condominium.....junk in, junk out...

What I am saying is that you have to start out with your ACTUAL weights AND hitch AND axles locations in order for the spreadsheet to start out .....AND....then you have to then enter the additional weights AND locations in order for the spreadsheet to return ACTUAL combined toad & trailer weight & balance. The more mass (weight) you put in your RV the more you have to account for your "loading". Partial water loads can be a source of weight errors as well as camping stuff and tools that change with various trip lenght.

 

We often RV with Dolly-the-paint-horse and often loading accounts for two tons of hay and 450 gallons of water and a 1,000 of misc horse stuff.....

 

Our toy hauler is very basic and we try to keep it fairly light (80% or less) and our truck is tandem so the more we load the truck the better the ride. We do have a 20 foot cargo box on the truck so we use to spreadsheet to keep the truck well balanced as well.

 

If you would like to play with the spreadsheet just email me at: mmcdan3189@aol.com

 

Drive on.....(stay well in balance)

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  • 7 months later...
On ‎9‎/‎2‎/‎2016 at 6:29 PM, skp51443 said:

I went looking to see if I could find some weight and balance software, there is some aimed at aircraft load-masters but I didn't see any free stuff or offerings for private pilots. Maybe someone has a spreadsheet or something similar that could help you with planning your balance but I didn't see it in my brief look.

 

Paper, scale and measuring tape will do the job so you can get to an answer with a bit of work.

 

Do you have an equalizing hitch? They won't increase your allowable tongue weight but they will let the truck ride closer to level and take some weight off the rear axle.

 

On your truck look at all the weights, combined, tongue and axles to make suer you are safe on each.

I was a Loadmaster on the C5 (Travis AFB). The original weight and balance computer Lockheed or their subcontractor designed, which was located in the sidewall near the troop door, never worked.  During my 6 years in the early 80's, we did it all by hand on a carbon copy forms... the good old days. :lol:

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