I built a couple sets of beach wheels using busted off stop signs- 2 1/2 inch aluminum tubing. NO I didn't break them off myself. Its a little heavy tho- great for 440 pound Hobies!
My new A-class Eurotrax beachwheels have an aluminum tube handle. Simplest possible- a smaller inner sleeve (stainless steel) on its end goes right thru the axle, and gets a machine screw pin stuck thru it to keep her on.
Remove and stash with the boom etc, for transport.
Why mess taking the wheels off to put on a T-coupling?

Repair question: I got a free set of commercial beach wheels , and they never worked: the nylon rod bearings are ok, but the inside of the axle (bonded to the tires) was apparently steel, badly rusted and very lumpy.
Did anybody ever try to clean-up and epoxy-glass inside?


Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison