Is It Tubeless-Ready?
 

[YES, I searched.]

If a non-mechanic was confronted with a pile of rims, how would he [she] determine if an otherwise unlabeled rim was tubeless-ready? Mind, the available documentation is a dev'lish place from which to make this determination reliably, loaded with hype and distraction as it is. What gives it away?

Many thanks...

put a tubeless tire (maybe even a non-tubless tire) on it and see if it holds air? or can even be pumped up... before even trying that i would probably look for sufficiently plugged spoke holes. this is from somebody that's never seen a tubeless clincher rim.

only hole thru it from inside out is for the the valve stem.

like a car wheel the valve stem is on it's own.

The art and science of mountain tubeless is a very grey area. Lots of ways to make stuff work, "tubeless ready" or not. Road tubeless is different in that you need to use only true "road tubeless" tires, because of the high air pressures involved; with the correct preparation, road tubeless tires can be used tubeless with most road rims, "tubeless ready" or not. Tubeless setups for cyclocross, generally speaking, have more in common with mountain tubeless than road tubeless, but are generally not as easy to set up reliably as mountain tubeless because of the extreme low pressures and high tire volume of mountain tubeless, comparitively.

With "tubeless ready" road rims, the term refers, as much as anything, to the way the rims are designed to optimize the air volume and roundness of the tires when mounted on the rims, and wider is generally preferable to narrower. Modern road tubeless setups haven't been used in the mainstream nearly as long as mountain tubeless, so things aren't nearly as evolved as they are in the mountain bike world, and honestly there's not the slam dunk advantages with road tubeless that there are with mountain bike tubeless. With mountain tubeless, most of the latest, more expensive rims and tires are marketed as tubeless compatible.

Personally, I'm a fan of road tubeless, having used various Hutchinson road tubeless tires for a few years now on different rims, and simply would not ride a mountain bike with inner tubes except in an emergency. I've used mountain tubeless, in one form or another, for at least a dozen years now.