They are likely stamped or molded with the load rating - either on the barrel of the wheels between the spokes or on the inside of the spokes.

 

Deleted will cause to many debates... LOL

 

Thanks, I'll take a look.

 

Actually, it’s the GVW that matters here, not curb weight. So about 510# more for each Miata wheel when used on a CX-5 (depending on year and model).

GVWs:
MX-5 = 2789#
CX-5 = 4828#

 

LOL deleted again, not worth having to defend my response !
The Mazda Miata wheels look GREAT on the Mazda pictured by the OP!!!!!!

 

Calli won't touch it
The wheel load capacity uses a standard formula and for all practical purposes it's an "estimate" arrived at from the vehicle standing still.
It's great for the purpose of the average driver but...
There is no way an engineer can take into account how you drive, where you drive (type of roads or lack thereof) and what condition your suspension is in.
I have a friend who's replaced two very expensive cracked wheels on his Sportsmobile Classic 4x4.
While it is a rugged vehicle, and the wheels would likely be fine for the normal off-roader, my friends driving is anything but normal when he's off road, and on road for that matter.
The wheels cracked not from "exceeding weight load" but because of the additional stress he put on them.

 

That's right because there is more information like you posted then most know or understand about wheels. And not many have custom wheels built either.

Thank you again for posting impressively well written information sir!