I love this! Congrats on the TC and the TT improvement! Good for you!

I spin a couple of times a week. Up here it gets cold enough that I don't really want to work at 100% and get dripping wet sweaty. While spinning we do aerobics as well as high intensity interval training. Even doing long hills when outdoor riding I typically try to stay "within myself" and not go into the red. When spinning you can ride as hard as possible until you're dripping and near collapse. I have fat tire bikes (2) and ride outdoors nearly all winter but I find spinning to be a big boon to getting a head start on my summer cycling.

I have done spinning classes for quite a few years in the winter when it gets dark early. The classes depend on the instructor--some are horrible and some are great. A fair number of them have never ridden outdoors and do all kind of things that are useless for training (hovering, and pushups on the bike come to mind), but others do a good intervals session that can motivate you to work very hard.

I like them because I can work hard, they're at a set time so I can't procrastinate, and I've found a couple of good instructors. I avoid or ignore the idiots, or skip certain parts of their workout.

Mark W

I made it to the climbing gym last night that has good spin classes.

Led by an ex racer, the class was pretty much all intervals,

ending with a segment where anyone could initiate 10 sec out-of-saddle sprints.

Didn't do any climbing routes afterward.