Raising trailer height

bejay1 wrote:
It looks pretty simple. The whole axel units is just that a "UNIT". It appeares to be similar to a wheel axel unit on a RR train box car; in that it is a unit that the box (trailer frame) attaches to.

Adding a spacer (full channel) to the frame (welding it to the frame) would allow the axel unit to then be bolted to the full channel length spacer. The verticle plate that exists would be simply modified to accomodate the needed horizontal bolt.

I see where there would be no change in the camber. The tongue height...(hitch ball)... would be adjusted to accomodate the additional 4-6 inch elevation.

The corner stablilizing jacks on each corner of the trailer could be made to come on and off with a little modification.....as they really are a "HANG UP POINT" when going down a 3-4 inch step from pavement to gravel etc. The spare tire that is underneath the trailer could be placed on a verticle rear bumper pedistal....as the spare tire hangs down a lot as well.

The trailer was not designed for anything other than hwy pulls and RV Parks.....as it really sits low to the ground.

Thanks for all the input and I'll see what transpires. Tks again.

bejay

It looks like you have it under control. Adding a length of channel (spacer) long enough to span at least across both axle mounts is a great idea. You may also want to consider gussets on the spacer in a few places to strengthen it.

When mounting the axles to the new spacer, you may consider running a string line under the trailer from the center of the rear of the trailer (exactly center between the two frame rails), to the center of the coupler (or the tongue jack since you probably can't get around it) and use this for alignment. With the string giving you the center of the trailer, with a little trig (1.4142 will give you the hypotenuse of a right triangle), you will be able to insure that the axles are perpendicular to the actual center of the trailer. If you use this method to check both sides of each axle from the string line you are going to get it as close as you reasonably can.

It is also very important to make sure that both of the axles are exactly parallel to each other so that the trailer tracks good. If you did the string step correctly, this step will just verify that everything is correct. You would be surprised how far off the factory trailers can be at times. Don't align the axles off of the factory work. Check the alignment to make sure it is correct.

Good luck and happy camping.

It looks pretty simple. The whole axel units is just that a "UNIT". It appeares to be similar to a wheel axel unit on a RR train box car; in that it is a unit that the box (trailer frame) attaches to.

Adding a spacer (full channel) to the frame (welding it to the frame) would allow the axel unit to then be bolted to the full channel length spacer. The verticle plate that exists would be simply modified to accomodate the needed horizontal bolt.

I see where there would be no change in the camber. The tongue height...(hitch ball)... would be adjusted to accomodate the additional 4-6 inch elevation.

The corner stablilizing jacks on each corner of the trailer could be made to come on and off with a little modification.....as they really are a "HANG UP POINT" when going down a 3-4 inch step from pavement to gravel etc. The spare tire that is underneath the trailer could be placed on a verticle rear bumper pedistal....as the spare tire hangs down a lot as well.

The trailer was not designed for anything other than hwy pulls and RV Parks.....as it really sits low to the ground.

Thanks for all the input and I'll see what transpires. Tks again.

bejay

Bejay1 the best advice I can give is rather than asking for help on here do yourself a favor and talk to a reputable frame shop in your area. They will be able to do what you need to have done safely that is what I did.

We have towed a lot of miles and had a lot of great camping trips since I made the changes.

You are correct, camber isn't required for them to work. It is required for them to work properly. Even your Dexter video shows the bow in the axle. If you notice that your axle mount is very close to the torsion arm which means the amount of camber (bow in your axle) will be less than one with a longer distance. It doesn't mean that your mount won't work. I'm just cautioning folks not to reinforce the center section of the factory axle mount at the point where it is made to flex. I'm not refering to the frame assembly that the axle mount attaches to. That part should be as strong as you can reasonably make it.

Also, from your pictures, it doesn't appear that the factory axle mount failed, it appears that it's attachment to the frame is what failed.

For those folks replacing axles, the Flexiride axles are what I have used almost exclusively for many years because they are the only ones that I know of that use a splined torsion arm so that you can adjust the axle torsion arm angle by just removing one large bolt and each spline will adjust the angle by about 6 degrees. It makes changing height (within reason) very easy. I used Dexter and Hayes (now Al-Ko) in the past, but Flexiride is much more adaptable. As far as making axles, you can buy them much cheaper than you can even buy the parts for them anymore. Southwest Wheel in Texas is a good supplier for the money.

Camber is not required for these axles to function.

Here are two photos of as axle failure which started the plans to modify the mounting. The primary was ST tire blowouts and plans to go to larger LT tires but seeing this failure influenced how the axles were to be remounted.

You will note that the frame was never drilled and the axle was only mounted to the side plates. The side plates failed due to side to side forces. They were lucky that it did not happen going down the highway as 65 mph.

Photo of failure--NOTE NO HOLES DRILLED INTO FRAME ALTHOUGH MOUNTING HOLES ARE PROVIDED.



Photo of failure ---Note IT WAS ONLY ATTACHED TO THE SIDE PLATE and the plate has been ripped from the frame.



I know that my mount is many times stronger than an original factory job and is much safer. The axles were aligned to the tow point and tracks perfect.

Do what ever you want.

brulaz wrote:

69 Avion wrote:

...
Those axles are "not" rigid to the frame. That axle mount is designed to flex even though it appears to be solid. That is how it allows the axle to flex.
...

OK, that makes sense. Dexter does provide the axle mounting bracket along with the axle as an integrated system. And as long as they're designed to flex (and don't fatigue/weaken as a result), there should be no problem.

And so to lift a trailer with Torflex axles, you probably want to just move the brackets down by thickening the frame with box steel or whatever. And not reinforce or modify the brackets themselves.

But it wouldn't really matter if the axles were never loaded to where the axle lost some camber, or if the axle load and resulting camber were relatively constant.

Which may be the case my 3500# rated Dexter Torflex axle. Even when loaded to within a 100# of the axle rating, it's noticeably bowed up and doesn't appear to flex much if at all.

I've read elsewhere on the web (for what that's worth) that the axle camber is designed to protect against extreme over-loading of the axles, and you don't really expect it to change under normal use.

There is a lot more to figuring out the bow (camber) in the axle than just using a press to put the bow in it. The distance between the mount and the hub face (not counting wheel offset) will be a major factor in the amount of bow necessary. That distance determines the amount of leverage on the axle. I think some folks confuse the suspension from the flex that occurs on the axle. They are different, but the susupension can influence the flex. For example, since a rubber torsion axle doesn't have an equalizer, one axle may at times carry the entire load. When that happens, the flex is increased on that axle and decreased on the other axle. It is one of the draw backs to rubber torsion axles. That is why a rubber torsion axle should be rated at 1.25 times it's intended load, when used as tandem axles. Example: 10,000# axle weight for a tandem trailer should have two 6,250# axles.
As you can see, the mount on rubber torsion axles are designed to flex. That is why they aren't "boxed" but mainly anchor on one side. It is also why you will notice that on one end the mounting bolt may be close to the axle but the other one is much futher away. This allows the mount to flex as the axle camber changes. If that flex is removed by reinforcement, something somewhere else "has to" flex. If the new part isn't designed to flex properly it may eventually fatigue and break. That is where the problem occurs.

69 Avion wrote:

...
Those axles are "not" rigid to the frame. That axle mount is designed to flex even though it appears to be solid. That is how it allows the axle to flex.
...

OK, that makes sense. Dexter does provide the axle mounting bracket along with the axle as an integrated system. And as long as they're designed to flex (and don't fatigue/weaken as a result), there should be no problem.

And so to lift a trailer with Torflex axles, you probably want to just move the brackets down by thickening the frame with box steel or whatever. And not reinforce or modify the brackets themselves.

But it wouldn't really matter if the axles were never loaded to where the axle lost some camber, or if the axle load and resulting camber were relatively constant.

Which may be the case my 3500# rated Dexter Torflex axle. Even when loaded to within a 100# of the axle rating, it's noticeably bowed up and doesn't appear to flex much if at all.

I've read elsewhere on the web (for what that's worth) that the axle camber is designed to protect against extreme over-loading of the axles, and you don't really expect it to change under normal use.

brulaz wrote:

Bonefish wrote:

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Each wheel acts independently and donot require camber in the middle of the axle (bow to you) for them to work properly and carry the load they were designed for.

Here is a video.

Dexter

But they do have camber, at least my 3500# Dexter does, even when fully loaded close to the GAWR. You can see it early in that video.

Frankly, I've never understood how the camber is supposed to work or what it's supposed to do, what with the axle's rigid attachment to the frame.

That was exactly the point I was trying to make. Those axles are "not" rigid to the frame. That axle mount is designed to flex even though it appears to be solid. That is how it allows the axle to flex. When someone welds that area or reinforces it, it has a hard time flexing and eventually something will give. I was just trying to delicately address the issue without offending anyone.

I wasn't trying to be arguementative, but just trying to point out some useful info for anyone interested. I've been building trailers on and off since 1975. I have used many axles of both rubber torsion and leaf spring type, and they each have their advantages.
The issue that I was trying to point out it that both axle types should have the bow in them(years ago I made my own axles). The rubber torsion axles are ONLY to be attached to where the bolt holes are. I prefer welding them on, but I only weld them where the bolt holes are and outward. Welding them (even with a reinforcing plate) around the center of the mount restricts the ability for the axle mount to flex as the axle is loaded with weight. Unless someone has an axle that defies the laws of physics, they will all flex.

Bonefish wrote:

...
Each wheel acts independently and donot require camber in the middle of the axle (bow to you) for them to work properly and carry the load they were designed for.

Here is a video.

Dexter

But they do have camber, at least my 3500# Dexter does, even when fully loaded close to the GAWR. You can see it early in that video.

Frankly, I've never understood how the camber is supposed to work or what it's supposed to do, what with the axle's rigid attachment to the frame.