Ron on Meander":330d0xkc said:
Does anyone have any ideas on how to check alignment?
Several things come to mind...none of which I have any direct experience with, but seem logical to me.
First thing I would do - ensure nothing is bent, prior to aligning anything. For the axles themselves, this would seem to be pretty easy - simply measure the distance between the rims on each axle at the 3 and 9 o'clock positions, and make sure they are equal. I'm assuming there's no need for toe-in or out on a fixed trailer axle, but that should be verifiable from the manufacturer.
For the trailer frame, maybe a bit tougher...perhaps find a common fixed point near the axles on each side, and measure up to the center of the hitch.
Once everything is verified straight, alignment shouldn't be too tough. Simply measure from the center of the front axle to the middle of the hitch, and ensure it's equal on both sides. This might be easier with the front tires/wheels removed.
Once the front axle is aligned, I'd mark the frame in some permanent fashion so you can easily see if things slip down the road.
Aligning the rear axle to the front, should be a piece of cake. Simply cut a couple pieces of wood to the same desired length, such that they fill the space between the axles at the frame. Use them as a jig to correctly space the two axles apart.
I'm sure somebody here has actually aligned axles on a tandem, and has something more than a hypothesis...but I can't see why the above wouldn't work pretty well.