Chains

One of the best ways to make an old bicycle feel young again is to change the tired old chain. Sometimes adding some bicycle lube will suffice, but if the chain hasn't been changed in years, you might as well just start fresh. It makes a big difference. My favorite chain right now is the SRAM PC-830. It's just like the PC-850 (formerly the PC-48), but it's cheaper. Why? I'm not quite sure. The PC-830 is a cheap but good chain, with SRAM's 'powerlink' connector which is nice if you don't want to fool around with pushing a pin out just enough with a chain tool and then getting a stiff link when you push it back in. That method takes practice to master, and you might as well avoid it.

The PC-830 is an 8 speed chain. That means that if the rear set of gears (freewheel or cassette) has six, seven, or eight cogs - you're all set. I suspect you'd be all set with a 5 speed freewheel too, but for that I use a different chain. So I dunno.

I ride bicycles almost exclusively with 6, 7, or 8 cogs on the back. That's all I want, and that allows me to use really cheap chains so I have no financial cringe when I want to keep a bicycle running smooth and quiet. If you ride with 6-8 cogs on back, the PC-830 is probably as good as you'll ever need. Look how expensive a 10speed (10 gears on the back wheel) chain is. There's no way I'm going to deal with that.