Originally Posted by Bklyn
Not sure whether they're alloy or steel. I can tell you that engraved near the valve is this:
UKAI 27 x 1 1/4 w/o LA Made in Japan.
Does that mean anything to you?
The "w/o" means "wire on", meaning it's a clincher, and "LA" likely means "light alloy", i.e. aluminum. You'll have to examine the rim walls to determine for sure if they're hook-edge or not. Since they're a quality aluminum rim, my guess is that they are-
edit: gotta give credit where it's due: the info regarding "w/o" and "LA" comes from Sheldon.