The Brooks Pro on my Schwinn Volare is pretty squeaky. I stopped on the way in today and snugged up the seatpost bolt. No change. I will try a small bit of grease on the rails this evening, but it doesn't seem to my butt like the squeaking is coming from there. Assuming it's some other part of the saddle, what would squeak?

The upside is that the squeaking is reduced if I focus on my spinning, which tends to keep my weight on the saddle more constant.

Could be your headset or bottom bracket.

It's from the tension adjustment hardware; it needs lubrication.

I gave my Flyer a shot of silicone spray and no more squeaks...

They will squeak, often the rails need tiny grease but also the leather itself can squeak depending on age, whether it rubs any part of post, skirt/no skirt tension, etc.

Trust me, a shot of lube on the adjusting hardware...

It sounds like the seat post if the noise stops when pedaling out of the saddle. I ran into a similar issue and just backed out one of the two bolts of the post at a time and relubed the threads. Also cleaned and relubed the seat rails and post clamps. Ideally, you should just take a little extra time and take the post out and clean and relube it completely. Just remember to mark the height with tape and eyeball the tilt with a level before disassembling.

As far as what could squeak, a lot of things. My #1 is the bottom bracket (or crank to spindle interface). Some others are: spokes on a wheel, headset, stem and handlebar, quick release skewers, etc.

Yes, no noise pedaling out of the saddle, and the sound seems metallic. I'll lube the adjusting screw. (I wouldn't have thought there'd be enough play, though I've never touched the nut.) Thx...