Bmblbzzz wrote:Is there a reason not to stock up on 8-speed chains at the same time as all those cassettes?
The main reason is that I don’t have unlimited funds to tie up in optional luxuries like stashes of bike components.
I have those cassettes. I have some spare SL-R400 down-tube shifters, because I like them and they won’t be sold forever. I got the shifters from a shop at close-out prices.
I don’t have rear derailleurs because suitable ones will be made for longer (I presently use a 10-speed RD-7800, but a wide range of suitable 8-, 9-, and 10-speed derailleurs were and are still being made. Besides, derailleurs last much longer than cassettes). Chains are consumables but several manufacturers still make 8-speed ones, and, as reohn2 points out, others will work anyway.
Thus the cassettes were the first priority. I find the Shimano 13–26T ideal. There aren’t many substitutes for that cassette if you like it and are fussy about your gearing. There are reasonable substitutes for any chain or derailleur.
Another thing I should have bought before they sold out was mid-range 10-speed 36-hole Shimano rear hubs. The 11-speed ones work with 8-speed cassettes but have worse dish for no benefit and dubious mechanisms for setting bearing preload.
I’m pretty sure you could make money buying any of these obsolete but timelessly good components, storing them carefully (so they don’t rust much), and trickling them onto the market in five or ten years. But I’ll leave that to someone else. I’m just buying for my own use because I can see the writing on the wall and intend to cycle for several decades.