I'm excited. I am almost 1/2 way to my Century mark. When I started a few weeks ago, I thought it would be good if I could do it in three months\ As it turns out, I might do it in a month. If all goes well, I might get a couple of these in before there is ice on the road.

In the meantime, I am using the spin bike on the days I can't get out to ride. Does anyone know about setting up the spin bike? I have the seat at hip-bone level, me leg is bent about 15* at the bottom of the stroke, my knee is directly above the pedal, and the handlebars are as high as they can go. When I spin, i feel o.k., but the next day my lower back is totally killing me. Something is wrong, and I don't know what exactly.. Any ideas?

Also, I was going to buy myself a real cycling jersey to celebrate my 1st century. They are pretty pricey online. Is there a place to find one that won't cost $50-60?

Thanks much!

Performance Bikes has jerseys that are relatively inexpensive, but plain.

Set your spin bike up so that it feels the same as your regular bike. So if your regular bike doesn't hurt your back the spinner shouldn't either. I am curious as to why are you setting your bars so high on the spin bike. Is that the same as your real bike?

Spinning can be surprisingly intense so be careful and don't overdo it. You do need some rest to recover properly from your exercise.

Try https://www.aerotechdesigns.com/ for a reasonable priced jersey. I haven't tried them myself, but I have some of thier bibs, and they are great.
As for the spin bike, try and set it up so it is close to the set up of your bike. Some have more/better/finer adjustments than others, so you might not get it perfect. It help to get somebody to look at your position to help identify any that might need adjustment that would be better seen from off the bike.
Do you use the same shoes as on your bike? Are they clipless?

I use the same shoes on both bikes. They are not cycling shoes, just regular shoes with toe clips.

Love2Pedal.com sells a lot of nice Primal Wear (and others') jerseys in that price range, and they have some plainer ones for less.

And don't do everything the instructor tells you if you feel it isn't a good idea. The classes I took over last winter had a leader who insisted on a couple of bits of low-rpm, high-resistance seated mashing as part of the routine. That might work for some people, but it's a recipe for disaster for my aging knees, especially in the off-season when I need to work on a mileage base that's more spin-oriented. I don't mind the lower RPM mashing if it's done while standing, but for me, doing it seated is a quick trip to the hurt locker.

What CraigB said. I have an ice pack on my knee as I type this. Lots of the spin instructors are not riders and will put you thru all manner of hoops during a class that has no relation to riding. Its a bit embrassing but if I start hurting during a mash a thon I settle into a fast cadence climb and sweat just as much. Might experiment with raising seat so your knee isnt quite so bent.