I'm cleaning up an Exage 500 mountain set I got off a fairly nice old Giant Prodigy hybrid. The intent is to put them on my cross commuter Cannondale frankenbike. I'm going to post here what I've learned as I go along. The shifters seem pretty well shot but the brakes and derailleurs and crank all look good. The date code on the parts is OI or September 1991.
Exage 500LX was fourth in a lineup of nine and the highest not to say "Deore" on it. The other designs were all basically the same shape, but the higher levels had more aluminum, meaning the 500 rear derailleur for example weighed about 60 grams more than an XT, with fewer seals and tension adjustments.
I've taken apart the rear derailleur RD-M500 GS. The knuckles are aluminum, painted silver. The cage and plates are steel plate that's been stamped pretty intricately. The cage and the left plate are plated. The right plate is painted black with the 500 logo printed on it. The hinges are all steel pins that are captured by smashing the aluminum behind them - I forget right now what the term of art is for this. The pins enter from the bottom and the top holes in the knuckles are blind so there's nowhere for water to collect and also gives it a really clean look. The high and low adjustment screws stick out the back. The tension on the cage and parallelogram are not adjustable, only the B-tension screw. The upper pulley is a "Centeron" which has a sintered alloy bushing rather than just being bare plastic. The 1990 catalog at Disraeli Gears shows this RD has a sprocket capacity of 12-30 teeth and a wrap capacity of 30 links.
A Clorox wipe took the RD's 500 logo right off - oops! The steel screws are all a little rusty but the plated and painted and aluminum parts are all just fine.
I'll edit with photos when things come out of the wash and come back together.