Sanity check - cassette interchangeability
 

I'm modernizing a vintage mountain bike, and will be building up a new wheel with a Tiagra FH-4500 hub. Will any Hyperglide 8/9/10 speed cassette fit? I'm considering a SRAM PG-850.

Also, will I need to monkey with spacers, or is it as simple as dropping the cassette onto the hub and buttoning it up?

As usual, Sheldon had the answer. Nevermind folks!

I'd go with a 9 speed system. I believe tiagra 4500 is a 9 speed system.

I'd prefer to go with 8 speed at this point. The cassettes are a lot more affordable and since I'll be using friction shifters, I'm concerned the spacing between cogs on a 9-speed cassette might make shifting a little squirrely.

yea good plan 8 speeds are adequate.. but the cog size range is where you make the gears
actually different.

13-28 vs 13-34,, the 'mega range' is like a 13-24, 7 speed + a 34t cog for hills.

9 speed cassette is just a "couple" $ more than 8 speed . Shop online-
MUCH wider variety of combinations to select from than 8.
You will need a 9 speed chain. $15-20

When I went from 8 to 9 with friction shifters my shifting was much more precise. It was just a matter of ergonomics between the shifter and my thumb. (8 was better than 7) YMMV