So if you don't have or never need to install torsion style axles, this thread ain't for you.

So awhile back I posted here when my Featherlite trailer got t boned by a 50K CV, and the impact ripped off the axles. The lawyers are still fighting.

So I got the new ones installed, and getting them aligned was a major concern.
I figured axles being parallel was more important then crabbing within reason.
However, the replacement axles were brand new, matched, and custom built.
The design of the axles is basically a 10" lever arm, which means it has arc for travel, and the spindles are mounted in rubber.
So I measured off the outer axle square tube housing and bolted/welded them in place. After install, measuring from the axles I got them withing 1/32". I was satisfied, and moved on.

After get all the finishing other touches done, painting, wiring, wheels mounted, etc, I decided to throw a tape measure on the axle centers and see how everything measured up.
I measured nearly a 1/2" difference between the axle centers side to side.

So I decided, well lets road test this and decide how to fix.

After the road test, I was back under a 1/16" variance.

The lesson as I see it, with this style axle, measure off the housing, as I guess the arcs aren't necessary the same or in the same exact orientation when brand new ,and the rubber likely has never fully set since the axle has never seen a load, is my guess.

so just how much will this new set move when fully loaded if it moved almost 1/2" empty ?
1/2" in the opposite direction ?
i can see the rubber moving some, but 1/2" seems excessive.
i wonder what the factory tolerance may be ?

as to the 1/2". a few years ago, the local chevy dealer received a new hunter frame machine. the representative was there to demonstrate new features and teach the techs how to operate it after the factory installed it and got it operational. the subject of the teaching demonstration was a new, just received, 4 wheel drive pickup off the lot. when it was checked, it was found to be over 5/8" out of spec [i forget which way] ! it was taken on a short drive and went down the road perfect, but to see that being a ton out from factory specs brand new was shocking to say the least.
it was checked several times, and the frame machine was re-calibrated several times as well, so the results were true. it was also checked a few times with strings and levels, and the results were very close to the machines measurements.

bottom line is, what do you expect to happen when loaded, and if remeasured changes again for the worse, can you reset it more to your liking ?

I guess I could accurately measure the lever arm, and then use the OEM specs to calculate the amount of arc possible and get a measurement og axle movement front to rear.. But since each axles arcs are independent of the other end, they may be at different points of the arc when installed, hard to determine, and also very hard to move.

Additionally the near 1/2" I measured was between the two axles compared side to side, so its possible each axle on one side was 1/8" to its opposite extreme away from each other axle, and the other side was 1/8" closer together, giving me my 1/2"measurement. How much of that 1/8" ? was arc travel and rubber misfit, I don't know.

Main thing, don't measure from the axle centerline when brand new and installing is my lesson.

Your trailer frame is probably not square.

As a result - your measurements will be off.

Trailer frames cannot be straightened usually after a major accident.

That is why trailers are totalled and scrapped.


Jim

We need air-ride car trailers. I have never seen one.

You can add air suspension or build a trailer with it.

I looked into that but it is too expensive.



Jim