I had a bad aluminum drum. I gave it away. Best to throw it away and move on to deal with something else.

I think you must have got a bad set, i have had no issues with them.
Now front rotors/discs are a different story i have seen a few of them but most warping was due to the owner not keeping the rears adjusted so the fronts were doing more than the major part of the braking.

Yeah Terry, that's what I've been thinking. I'm wondering whether or not I'll need to get the aluminum Cooper S style drums or maybe KAD drums. Or, I could just put my old normal Mini drums with the tons od spacers back on...

I have an old pair of Minifins. I am not sure they are worth the extra cost. I just replaced with standard for the MMW trip.
Terry

Yeah Terry, that's what I've been thinking. I'm wondering whether or not I should get the aluminum Cooper S style drums or maybe the KAD ones.

Craig, I think part of it is the variation in manufacturing we are seeing for many items. Material not up to specs.
Terry

I don't know about the drums you mention, but drum warping was attributed to leaving the handbrake on after a drive that left the drums hot. The pressure of the shoes would set the drum in an oval shape.

I've searched here to see if there is any information on the cast iron brake drums available today, but couldn't find anything.

I have the cast iron Cooper S style rear brake drums and from the start they were out of round. I took them to a local machine shop to have them trued, but that failed to make them round for very long. They grabbed a bit less when I put them back on, but have gotten worse over the last thousand miles or so of driving.

Are these drums prone to warping? Are the aluminum drums more stable? I'd really like to know!!!