Flexiride Half-Axles

[Alphacarina]

They're the makers of Flexiride

http://www.ucfamerica.com

Don

[Alphacarina]

Andrew,

There definitely is camber built into these half axles, just as there would be with a sold axle which is bent slightly in the middle

With these half axles, the mounting plate is angled about a quarter of an inch from one end to the other - You can't see it in their pictures, but it's really obvious when you see them up close

Don

[angib]

You can't see it in their pictures, but it's really obvious when you see them up close

Good info, Don - the photo that you're taking as I write will show it clearly, eh?

Andrew

[Alphacarina]

I knew it . . . . I just knew it - Eventually, one of you was going to force me to set up an album, figure out how to upload pictures to it and then how to post them to a thread - You get the 'honors' Andrew

Actually, it wasn't all THAT bad . . . . Mike has things pretty well orgainized here

As you can see, the camber is welded into the mounting base, so if you mount the half axles to a crossmember, in a straight line, everything's already taken into account for you . . . . but it means I can't mount them to the top of my frame like I had originally planned



Don

[SteveH]

I have a question about the stub axles and maybe one of your "experts" can answer. I understand there must be a cross member at the axle's mounting location, but must there be two cross members, or a very wide crossmember to handle the load torque applied to the mounting plate?

[Alphacarina]

I don't think you have to have a cross member at the mounting location - One of the reasons many folks go with the stub axles is because they want to have a dropped floor in the middle of the trailer and that's only possible with stub axles

You would need very inflexible side rails on your frame though - One or more cross members somewhere near the axle mounting points to keep any flex out of the frame rails. I'm using a minimal 2 x 2 boxed frame rail made of 11 gauge material, so for me, a crossmember right at the mounting location is almost a must, but with a beefier frame, all sorts of other possibilities would be viable

Don

[SteveH]

Don,

I'm sorry, but I cannot imagine a frame side rail that is so ridgid it would not torque bend without a cross member where the stubs are mounted. Can you show me an example of a successful trailer frame so built?

[angib]

1) A single cross tube is quite sufficient for mounting half-axles. The technique often used is to use weld a mounting plate under the cross tube so that the bolts pass in front of, and behind, the cross tube. That would be the right hand side of this diagram:



2) The yachts I used to build went on trailers that didn't have a cross tube between the half-axles as the keel bulb sat there. However, there were two side rails each side and there were cross tubes in front of and behind the keel box, so the half-axles weren't exactly unconnected.

I think the boat hulls looked gorgeous, so I'll post this photo I found on one sitting on a trailer:



Andrew

[asianflava]

That must need a really steep boat ramp.

[SteveH]

That must need a really steep boat ramp.

Yea, or a very long extendable tongue!

Andrew,

Could you possibly give us a drawing of: "there were two side rails each side and there were cross tubes in front of and behind the keel box, so the half-axles weren't exactly unconnected."

Not sure I understand that discription.

[Alphacarina]

If the frame rails are substantial (like a heavy 'I' beam) then the cross rails can be well in front of and well behind the wheels, like the boat trailer Andrew pictures - The stub axles are connected only to the side frame rails . . . . because a cross member where the wheels are would be in the way of the keel - Just as it would be if you wanted a dropped floor in a teardrop, so instead of using a conventional axle, you could use stub axles

They don't usually back those type trailers into the water - That's what marine travel lifts are for . . . . and that's what they do with old, recapped 727 tires

Don

[brian_bp]

...Since I'm using FWD automotive alloy wheels, I'll have to order me a pair of 2 inch spacers, since the bore on my wheels is smaller than the hubs . . . . but then it looks like I'll really need that 2 inches anyway to keep the inner part of the tire away from the arm

Typical FWD automotive wheels have 35 mm to 50 mm (1-3/8" to 2") of offset, meaning the wheel mounting face is that far outboard of the wheel centre plane. Trailer hubs are usually designed for about zero offset... so a couple inches of spacer should put the wheel centre back to about where it should be, and would be needed for a proper installation even if there were no clearance problem.

I'm guessing these are 5-on-4.5" hubs, with 5-on-114.3 mm wheels. I would do the same thing with my travel trailer and my Toyota van wheels, but even with 2" of spacer the wheels centre bores won't clear the end of the hub. What car do the wheels fit?

[brian_bp]

If the frame rails are substantial (like a heavy 'I' beam) then the cross rails can be well in front of and well behind the wheels...

Since the stress on the frame rails due to the lack of a crossmember is in torsion (tending to twist the rails), an I-beam or C-channel would be inferior in this respect to a closed box rail.

[brian_bp]

I don't think you have to have a cross member at the mounting location - One of the reasons many folks go with the stub axles is because they want to have a dropped floor in the middle of the trailer and that's only possible with stub axles...

The separate axles are handy for dropped floors even if you do put a crossmember right at their location: the crossmember can be under the floor, and well under the height of the axle components, unlike the in-line integrated crossmember of a one-piece axle assembly.

[brian_bp]

I have a question about the stub axles and maybe one of your "experts" can answer. I understand there must be a cross member at the axle's mounting location, but must there be two cross members, or a very wide crossmember to handle the load torque applied to the mounting plate?

The other responses have address the stress which tries to collapse the frame in on itself (extreme negative camber, as the frame rails twist and the tops of the tires approach each other). The other stress involved with the mediocre brackets on most of these half-axles is twisting around the pivot axis of the suspension arm: this is bending the frame rail, and maybe that's why the question about two crossmembers. The mounting brackets should really extend so that they mount to the frame rails forward of and behind the axle (wheel centre) line, like the brackets on one-piece axle assemblies.

The only nicely bracketed half-axles I've seen are the custom-made Dexter set... now if I could remember which T&TTT member has them...