Half Torsion Axles

[toolbox]

Is there an advantage using a half torsion axle, as compared to using a solid bar torsion axle that is ordered to fit the trailer width?


www.etrailerpart.com sells both types. Is there any operating/adjustment differences between the two?

Dave

[madjack]

...if you decide on the half axles(either will work just fine) go here for possibly better prices, they are the manufacturer
madjack

[bledsoe3]

One advantage of the half axles is weight. The disadvantage (at least for me) would be trying to mount them in exactly the same place and square with the frame.

[asianflava]

One advantage is that it would allowed for a dropped floor past the wheels.

[SteveH]

The advantages I see is weight, which Bledsoe3 already mentioned. The disadvantages, as I see it, the frame needs to be built for the units you are using with a cross member in the correct position to place the wheels in the correct position. This means you must have an accurate estimate of weights to get the tongue weight you want, because to move the axle/wheels would necessitate moving or adding a cross member.

Rocky, because of the need for the crossmember between the units, I don't see how you could have a dropped floor in that area.

[TRAIL-OF-TEARS]

I used the full torsion axel as part of the frame structure.
Steve, why do you need a cross member between the units? and if that is the case you really are not saving that much weight.

[SteveH]

Steve, why do you need a cross member between the units?

Steve J.,

Because without a cross member where the units are mounted, the load being applied to the spindle, which is of course outside of the frame, will twist the frame sides.

If you look at how the stubs attach, they attach at the frame side rail, and then inboard from there. If I were building a frame for stub tortion units, I'd put two cross members where the stubs go, one set for the front bolts of the units and one set for the rear bolts. However, I tend to overbuild things.

[angib]

A cross member is needed to carry the bending loads between the torsion units. So it would be right to say that this is just replicating an full torsion axle, except that you can use the cross member as part of the frame - for example to hold up the floor, in a way that you can't with a full axle. A full axle also limits you to providing two longitudinal frame members to fix it to - with half-axles you are not limited in this way.

As I've said before, half-axles are the 'norm' over here and so using them is normal too. Getting them pointing straight ahead, to a sufficient accuracy, is no problem - this is trailer-building, not rocket science! Here are a couple of popular designs to fix the blue half-axle to the red cross member:



It is usually easier to bolt the half-axle to its mounting plate, align the plate/axle using the wheel mounting flange, tack weld the plate and then unbolt the half-axle before fully welding.


Andrew

[TRAIL-OF-TEARS]

thanks Steve and Andrew that makes perfect sence forgot about the bending (twisting) of the sides of the frame.

[cracker39]

This brings up another possible change in my design. I first looked at the individual torsion units, but discarded the idea in favor of a single axle. Am not considering the individual torsion units again. If I did, I'd only weld up the outside frame rails and one or two smaller angle iron floor supports and after balancing the load for axle placement, weld in the main "center" tube crossmember where the torsion units would go, to support them. Some weight would be saved, but only about 15-25 lbs, depending on the thickness of the axle shaft tube. The construction time would be about the same, so there's no advantage there that I can see.