Where to put generator in 21' travel trailer

bpounds wrote:

Fisherman wrote:
Maybe some of you naysayers should go see your local high school physics teacher and have him explain what happens when you add weight, not at the pivot point which would be the trailer axle but more likely 7-8 feet behind the pivot point. If it's a 50lb genny, at the axle it would exert 50 lbs, at distance of 7 feet it would exert about 350 lbs, be it down due to gravity or add that amount to sway, something not desirable.

You might want to see your physics instructor and ask for your money back.

A typical travel trailer (TTT) has about 15% weight on the tongue. 50# added at the bumper would remove about 42.5# from the tongue. That might screw up the handling of some TTT, but that would be rare. A 21' TTT weighs around 6k# GVWR, so you can expect tongue weights in the 900# range. And that's before we complicate the calculations with a WDH.

And all that is before we even consider the empirical data of about 10,000 people out there who have done this exact thing. Hell, my trailer even has a roll-out tray at the rear for cargo. I think it has a 200# rating IIRC.

bpounds, you might need to hit the physics books yourself.

50 lbs on a TT bumper will not remove anywhere near 42.5 lbs from the tongue.

I actually HAVE done this as an experiment for my 100lb gen. I put 100 lbs of concrete blocks on the rear bumper and measured just under 1/3 of the 100 lbs being removed from the tongue (30-32 lbs).

For myself, I would never notice 30-32 lbs missing from a tongue weight of 850-900lbs when loaded (which is at 15% TW)

Has to do with the location of the pivot point and a TT actually has the axle placed approx 1/3 the way from the rear bumper, 2/3 the way from the tongue..

Longer trailers have more rear "overhang" but they also have more distance from tongue to pivot point at the axles..

Think of it in the terms of a playground teeter totter..

It is all about maintaining 10%-15% tongue weight..

You can also use a bit of math to figure it out also..



For more in depth material, Dexter axle has a lot of good detail and theory for axle placement..

In the end, I scrapped the idea of carrying the gen on the back of the trailer and it had nothing to do with tongue weight or even frame damage.. More practical sense since running a gen is going to be loud, gen will transmit every vibration to the trailer frame and box and then there is the Carbon Monoxide issue to deal with..

I would rather not have a gen that close to my trailer operating for the noise, the vibration and Carbon Monoxide poisoning.

As they say, three strikes and you are out..

In the mid 70's my parents had an 18' aristocrat lo-liner (sp).
They had a bike rack added to the back of the trailer attached to the frame.

We ended up jack knifed on the side of the san diego freeway - once and then at the bottom of the grapevine north of Los angeles.

sometimes it doesn't take much to change the weight on the tongue enough to cause a problem.

Given this posting is from august of 2020, I would assume the OP has moved on, but for those of us who are still adding to the thread, changing the weight, can in some instances have dire effects.

bpounds wrote:

Fisherman wrote:
Maybe some of you naysayers should go see your local high school physics teacher and have him explain what happens when you add weight, not at the pivot point which would be the trailer axle but more likely 7-8 feet behind the pivot point. If it's a 50lb genny, at the axle it would exert 50 lbs, at distance of 7 feet it would exert about 350 lbs, be it down due to gravity or add that amount to sway, something not desirable.

You might want to see your physics instructor and ask for your money back.

A typical travel trailer (TTT) has about 15% weight on the tongue. 50# added at the bumper would remove about 42.5# from the tongue. That might screw up the handling of some TTT, but that would be rare. A 21' TTT weighs around 6k# GVWR, so you can expect tongue weights in the 900# range. And that's before we complicate the calculations with a WDH.

And all that is before we even consider the empirical data of about 10,000 people out there who have done this exact thing. Hell, my trailer even has a roll-out tray at the rear for cargo. I think it has a 200# rating IIRC.

......AND those that give NO thought to loading their rigs then tossing in a weekends worth of firewood, chairs,and who knows what else to the bed of their pickups then driving off to who knows where. Ever consider that when you have 4 passengers in your car and a load of groceries or beach gear .skis on the rack up top a full tank of fuel and your mother-in-law in the front seat that you may be overweight? ohhh....that's right, cars magically figure all of that out for you and keep the vehicle straight on the road. (chuckle.grin roll eyes)

We are talking about 50 pounds...not 500. Imagine if he wanted to add a spare tire to the rear bumper....ohhh the humanity!!

Fisherman wrote:
Maybe some of you naysayers should go see your local high school physics teacher and have him explain what happens when you add weight, not at the pivot point which would be the trailer axle but more likely 7-8 feet behind the pivot point. If it's a 50lb genny, at the axle it would exert 50 lbs, at distance of 7 feet it would exert about 350 lbs, be it down due to gravity or add that amount to sway, something not desirable.

You might want to see your physics instructor and ask for your money back.

A typical travel trailer (TTT) has about 15% weight on the tongue. 50# added at the bumper would remove about 42.5# from the tongue. That might screw up the handling of some TTT, but that would be rare. A 21' TTT weighs around 6k# GVWR, so you can expect tongue weights in the 900# range. And that's before we complicate the calculations with a WDH.

And all that is before we even consider the empirical data of about 10,000 people out there who have done this exact thing. Hell, my trailer even has a roll-out tray at the rear for cargo. I think it has a 200# rating IIRC.

okhmbldr wrote:
You might try this test before moving forward. Get a really good scale and position it under the hitch at the ball point then check the tongue weight. Then get a 100# kid/person to stand on the rear bumper. Check the tongue weight. Add another 100# person, check the tongue weight. That will tell you how much tongue weight you will lose by adding the generator/carrier to the rear area. Then you can compensate any tongue weight loss by loading the inside of your trailer heavier at the front to get back to a good balance for your trailer.

I like your common sense approach to this. A lot of thoughts on how adding a generator will affect the tongue weight but no real solutions. I towed a 16 ft. trailer on the rear of my "C'

motorhome loaded to the legal limit and didn't feel any difference in handling, if anything it helped plant the coach firmer on the ground and felt better in the wind. A lot has to do

with what your tow vehicle is also.

You might try this test before moving forward. Get a really good scale and position it under the hitch at the ball point then check the tongue weight. Then get a 100# kid/person to stand on the rear bumper. Check the tongue weight. Add another 100# person, check the tongue weight. That will tell you how much tongue weight you will lose by adding the generator/carrier to the rear area. Then you can compensate any tongue weight loss by loading the inside of your trailer heavier at the front to get back to a good balance for your trailer.

aguablanco wrote:
I just installed the Mount n Lock arms and Safety Struts on my rear bumper and, so far, I couldn't be happier. I would post a couple of pics if I could. Look this product up and I think your problem will be solved. If you read the reviews on a website with the same name as a South American river you will see my pics of my Champion generator and 2 five gallon cans.
RichH

I did this on a 30 ft fifth wheel. Hauled my 158 lb generator about 10000 miles with no issues.

TurnThePage wrote:
Shorter trailers will have much less bounce back there. I think you can do it. I put a rack on the tongue of my trailer for the generator and decided it was just too much work to get the generator all the way up there, not to mention the extra noise from it being so elevated.

As long as it's secured firmly to the frame and doesn't offset the tongue weight too much, it sounds like a good option to me.

I think the bigger issue with such a relatively short trailer will be the axle placement. The weight of the generator could easily upset the handling characteristics.

klutchdust wrote:
"Doing such a mod, will likely void the frame warranty if something happens. "

Curious as to how many trailers have had frame issues that were under warranty. I have seen two fifth wheels with cracks

up front but that was after many years of service and loaded to their maximum weight rating constantly. A 21 foot trailer has

what two main frame rails and some crossmembers. Any issues that do come up, and highly unlikely, could be repaired by

the fabricator making your hitch. As a professional mechanic and welding since I was a kid I have some background. I say do it.

Our previous RV (bumper pull toy hauler) had a major frame defect. Luckily it was covered under warranty ahead of a massive recall and attempted class action. The details are chronicled in the "WW Repairs" sticky thread in Toy Haulers, if you're bored and want to read some RV history.

Personally, I would take the frame's warranty seriously. Our rig was a rolling total loss without their repairs.

"Doing such a mod, will likely void the frame warranty if something happens. "

Curious as to how many trailers have had frame issues that were under warranty. I have seen two fifth wheels with cracks

up front but that was after many years of service and loaded to their maximum weight rating constantly. A 21 foot trailer has

what two main frame rails and some crossmembers. Any issues that do come up, and highly unlikely, could be repaired by

the fabricator making your hitch. As a professional mechanic and welding since I was a kid I have some background. I say do it.