60/40 Rule Rocks

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Re: 60/40 Rule Rocks

Postby dancam » Mon Oct 02, 2017 4:30 pm

60/40 looks like it works very well for teardrops. I have a feeling it all has to do with weight distribution so it may be different for other trailers. Doesnt matter how far back the axle is, if there is more weight behind it than in front it will swing.
I think (but i dont know) that if you had a tire come off a trailer that had its axle in the middle but 20% of the weight on the tongue it would still pull straight.
On my trailer i moved the axle ahead quite a ways ahead to be 60/40 on the box but i have significant weight on the tongue so i am going to have issues with keeping the tongue light enough for the tv. However i have a 2ft overhang at the back so it looks goofy.
I have seen fairly light trailers flip pickups on their sides. It depends on how bad you have it loaded and the wheelbase of the tv as well.
I was pulling a borrowed 14ft double axle bumperpull dumpbox trailer with an old f350 that was a full cab and box- 21ft bumper to bumper. The guy that loaded me quite heavy with wet sand put too much weight behind the axles. As i was speeding up i was watching the trailer. As soon as i hit 80kmh the trailer started to swing. I let off the throttle and hit just the trailer brakes hoping to slow down gently and steady. No trailer brakes. By the time i hit the truck brakes and stopped that trailer was swinging back and forth into 4 lanes of (empty) highway and nearly hitting the bumper of the truck on each side. But guess what? If i hadnt of looked back i wouldnt have known it was happening. Couldnt feel a thing in the truck. Luckily no tires blew so i just shovveled sand for a very long time and then finished my trip. But that was interesting.
I also think anything big or heavy is stupid to pull from a bumper instead of gooseneck style, but whatever.
Look at semi trailers. They have the axles all the way at the back because the truck is designed to take a lot of weight. You never see those sway.
Proper weight distribution is key, 10-15% is sort of a minimum, not a maximum or optimal. i used to work for a guy and we had a trailer that just had to be loaded improperly every time. Trailer was too short and with the machinery too much weight ended up behind the axles, no other way to load it. Double axle bumper pull trailer with the axles fairly far back. My boss could drive it fine with his dodge 2500. He would try and get me to drive it when he was drunk but i couldnt. It would start to sway every time i went around a corner. He could drive that better drunk than i could sober, so i would just keep him awake.... :/ i cant believe i rode with him like that...
Anyway, you do want to keep the weight on your front axle of course but how was that 1/4inch guideline come up with? Front axle of an f350 empty is like 4000 pounds but 200 pounds/side will likely move the ride hight 1/4inch. The driver sits a ways back in any suv but them sitting in it will move the front suspension 1/4inch. By that guideline you couldnt anything more than a heavy teardrop with a dodge pickup probably.
It would have to do more with what % of the weight your taking off the front axle i would think.
You loose traction as you remove weight from the front if your tires are properly sized but you get it and more back when you brake and weight is transferred to the front axle from the trailer. Image

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Re: 60/40 Rule Rocks

Postby Camp4Life » Tue Oct 03, 2017 8:53 am

Like I said, the 1/4 inch thing (and I'm talking the FRONT axle RAISING) is just another ballpark for a car. Truck or SUV I'd say closer to 1/2 inch. Basically, if your front is raising, then there's weight being taken off the front wheels, which is not good. The rear suspension should compress well before the front starts to raise.

Here's my trailer off and on the truck:

Image

Image

Yes I need a riser hitch to bring it up 1 inch or so. Anyways, the trailer is 5000 lbs. The front fender doesn't raise at all even though the rear fender drops an inch. My trailer and tongue weight is also below my hitch carry weight and below the 15% limit. The tandem axles really help, and the trailer is very nicely balanced (AC is right above the axles, fridge, stove and furnace are behind the rear axle, bathroom is at the back. Dining room and bedroom at the front as well as hot water tank and fresh water tank. With all this, I do not require a WD hitch, although having one would help level the truck that 1 inch, it's not needed.

The trailer tows like a dream and I can't even tell it's there.
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Re: 60/40 Rule Rocks

Postby John61CT » Tue Oct 03, 2017 9:32 am

Building a custom deck-over with a drop-floor from the frame up, i.e. from scratch.

No idea of my final weight distribution in advance.

Could maybe put on the suspension last, but imagine I'll change the layout over time anyway.

Any pointers to a design, or suspension components that allow shifting the mount points forward and back as needed, relatively easily.

Bolted rather than welding?

What about raising the whole frame for off-road boondocking, then lowering for back to blacktop?
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Re: 60/40 Rule Rocks

Postby Aguyfromohio » Tue Oct 03, 2017 12:30 pm

John61CT wrote:Building a custom deck-over with a drop-floor from the frame up, i.e. from scratch.

No idea of my final weight distribution in advance.

Could maybe put on the suspension last, but imagine I'll change the layout over time anyway.

Any pointers to a design, or suspension components that allow shifting the mount points forward and back as needed, relatively easily.

Bolted rather than welding?

What about raising the whole frame for off-road boondocking, then lowering for back to blacktop?


You may like a Flexiride solid axle .
We just bought and installed a pair, one for each trailer, and like them.
The mounting bracket fits nicely under a rail of angle iron, bolted on where you can reach it, so you can move it forward and back to find the best location.
The trailing arm is on a spline that you can remove pretty easily. Take off the wheel and tire; take out one bolt; pull it off the spline.
Push it back on at a new ride height/angle, reassemble. One jack stand and 45 minutes to change ride height on both wheels.

In our build the frame rails are square tube rather than angle, so the head of the mounting bolt head is down inside the tube,the nut down at the bottom end exposed.
Once we put the wall over the rail we cannot get back in to move the axle. Next time we will use angle rails so we can shift the axle like you prefer.

Many folks build with the Flexiride half axles, but like you I did not know where the axle would end up, so I could not put reinforcement for the half axle wherever it ends up.
The full axle solves that.

Torflex and others make nice torsion axles with similar mounts but as far as I know only Flexiride has the adjustable ride height we wanted.

Image
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Re: 60/40 Rule Rocks

Postby John61CT » Tue Oct 03, 2017 2:54 pm

Nice.

I like the half-axle idea for clearance, I guess just means closer spacing of floor crossmembers right through that general area (where you might move it to) for reinforcement.

And I suppose it makes adding a tandem later as well.

I saw Timbren's version, but no vertical adjustability, just lift/regular/drop versions at purchase time.
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Re: 60/40 Rule Rocks

Postby Aguyfromohio » Tue Oct 03, 2017 7:17 pm

John61CT wrote:Nice.

I like the half-axle idea for clearance, I guess just means closer spacing of floor crossmembers right through that general area (where you might move it to) for reinforcement.

And I suppose it makes adding a tandem later as well.

I saw Timbren's version, but no vertical adjustability, just lift/regular/drop versions at purchase time.


The half axles seem to mount differently than the full axles
Which makes sense because the forces are different on a half axle- the weight on the wheel wants to twist the frame rail.
Without the center beam across the full axle to resist that moment it must be opposed by frame members right near the hub. I decided on the full axle early on so I did not look into it that deeply, but the mounting seems quite different and harder to shift to a new location


Image
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Re: 60/40 Rule Rocks

Postby John61CT » Tue Oct 03, 2017 7:48 pm

Yes, looking at a few factors wrt the half-axle design, I'm thinking Timbren may work better for my use case.

As you point out, the Flexiride mounting plate extends sideways into the middle of the trailer, so my ability to relocate front to back would not be as incremental, unless a very wide frame rail platform is created on both sides.

Therefore, Timbren creates much greater high-clearance area in the middle between the two half-axles, where for example I'd like to hang/store under/into the floor deck plane, propane and the other heavy water tank loads.

It is true the Timbren's longitudinal axis mounting requires crossmember framing to resist the twisting/torsion force, but that doesn't necessarily need to be attached directly to the main frame rail, but possibly incorporated into a lateral "box frame" raised above and/or below, depending on whether using the dropped or lifted model axle, which choice gives a full 8" range of height difference and regular in between.

The Flexiride deflection is not great, it seems to me that will transfer more shock to the trailer/contents compared to Timbren.

The Flexiride unique vertical adjustability is not actually over a very wide range, gains maybe an inch or two and lifting that little bit sacrifices even more deflection / shock absorption.

Finally, it seems like the Timbren's rubber spring/airbag and other wearing components would be much more easily field replaceable, and also cheaper.
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Re: 60/40 Rule Rocks

Postby DestinDave » Tue Oct 03, 2017 9:34 pm

WOW! That'll mess up your drawers! :shock:
Glad everything is OK :thumbsup:

I started out shooting for a 60/40 ratio of the deck length but ended up with closer to 65/35.. I also am shooting for 10-15% of total weight as the tongue weight.. I think I'll be close to that as well but won't know for sure until I mount the box and batteries on the front and drag it over to the truck stop for weighing.. Fingers crossed.
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Re: 60/40 Rule Rocks

Postby ssuuki19 » Fri Oct 06, 2017 1:42 pm

This thread is a very poignant discussion for me as I will be testing out my all aluminum trailer setup with half axles, very, very soon, perhaps some of the readers will be interested in the observation/results. With that one general rule with a 9 foot box the axle should be nine inches to the rear - I think coincidentally thats about where the half axles line up as they had to be mounted right where a cross beam was (because of the wanting to twist the frame rails as mentioned). I thought 8-12% tongue weight was a general rule but I see you are mentioning 10% minimum.
The first road test of my setup will involve taking the empty car and trailer to the scales to get all the axle weights.. in my case I have two advantages in the design:
1) car has airbags installed in the rear springs so I can level the rear once the tongue weight is applied - can't recommend airbags enough, they are cheap and easy
2) cabin can be moved forward 12" - 20" and re-bolted to the frame, to fine tune the tongue weight if its way off - guessing tongue weight will be too little to start
I'm new to this setup, excited to see how it works out..after the weighing session is done I will post back the results compared to the 60/40 rule.

How does sealant get on my triceps and then my car seat?? more than once??
Aluminum is almost as fascinating as wood.
Link to my build thread: 4 1/2 x 9
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Re: 60/40 Rule Rocks

Postby John61CT » Fri Oct 06, 2017 10:12 pm

ssuuki19 wrote:
2) cabin can be moved forward 12" - 20" and re-bolted to the frame, to fine tune the tongue weight
So you end up with that much unused deck either front or back? Or have you got a light load item to park there? I'm thinking winter clothing, bedding. . .
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Re: 60/40 Rule Rocks

Postby dancam » Fri Oct 06, 2017 11:13 pm

John61CT wrote:
ssuuki19 wrote:
2) cabin can be moved forward 12" - 20" and re-bolted to the frame, to fine tune the tongue weight
So you end up with that much unused deck either front or back? Or have you got a light load item to park there? I'm thinking winter clothing, bedding. . .
This photo is from his build thread, not really any unused space, just room to move, lol. Image

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Re: 60/40 Rule Rocks

Postby dancam » Fri Oct 06, 2017 11:15 pm

ssuuki19 wrote:This thread is a very poignant discussion for me as I will be testing out my all aluminum trailer setup with half axles, very, very soon, perhaps some of the readers will be interested in the observation/results. With that one general rule with a 9 foot box the axle should be nine inches to the rear - I think coincidentally thats about where the half axles line up as they had to be mounted right where a cross beam was (because of the wanting to twist the frame rails as mentioned). I thought 8-12% tongue weight was a general rule but I see you are mentioning 10% minimum.
The first road test of my setup will involve taking the empty car and trailer to the scales to get all the axle weights.. in my case I have two advantages in the design:
1) car has airbags installed in the rear springs so I can level the rear once the tongue weight is applied - can't recommend airbags enough, they are cheap and easy
2) cabin can be moved forward 12" - 20" and re-bolted to the frame, to fine tune the tongue weight if its way off - guessing tongue weight will be too little to start
I'm new to this setup, excited to see how it works out..after the weighing session is done I will post back the results compared to the 60/40 rule.
How are you planning to weigh your trailer?

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Re: 60/40 Rule Rocks

Postby DestinDave » Sat Oct 07, 2017 9:59 pm

dancam wrote:How are you planning to weigh your trailer?

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Many truck stop plazas have a scales and will weigh your trailer for a nominal fee.. locally, I believe it is $10.. that's what I plan to do soon.
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Re: 60/40 Rule Rocks

Postby drhill » Sun Oct 08, 2017 10:40 am

dancam - I would think that there would be a self weigh scale somewhere in Nisku. Ask the next trucker you talk to.

Doesn't help you much, but in the Calgary area there is a self weigh just West of the Petrocanada at Hwy 1 and 22 and just South of the Petrocanada on Hwy 2 near Aldersyde. There are likely some self weighs in the Edmonton area too. The other option is the scale at the landfill, but it seems to me that is way East of Edmonton.
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Re: 60/40 Rule Rocks

Postby dancam » Sun Oct 08, 2017 1:12 pm

drhill wrote:dancam - I would think that there would be a self weigh scale somewhere in Nisku. Ask the next trucker you talk to.

Doesn't help you much, but in the Calgary area there is a self weigh just West of the Petrocanada at Hwy 1 and 22 and just South of the Petrocanada on Hwy 2 near Aldersyde. There are likely some self weighs in the Edmonton area too. The other option is the scale at the landfill, but it seems to me that is way East of Edmonton.
Im not worried about where to weigh mine, just was wondering about him. I saw on his build thread he just went over a scale, but didnt say where. Said it was 720 pounds but im not so sure about the accuricy of the semi truck scales down to calling it 720 pounds rather than 700 or 800 or 600... they are meant to weigh 140,000 pound trucks and the scale being one or 2 or 300 pounds off may not concern them too much.
At 720 pounds he can still measure it using a 400 pound scale if he has one available to him. Or even a 300 pound scsle if its used as mentioned elsewhere on this site to take half the weight of one tire.

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