How important is chain speed designation with its compatibility to chain sizes. I have an 8 speed drivetrain and may want/need to get a new crankset, move to a compact possibly, and everything i look at lists 9 or 10 speed it seems. I want to know if I need to get an 8 speed, and what the difference is exactly (in regards to chainrings)

I want to keep it at 8 speed because I can still friction shift with my DT shifters (they are only indexed to 7) and because 8 speed to cheap to maintain and replace.

There are plenty od 8s chains out there, and at good prices. However 7s and 8s use the same chain, and some are listed as 7s.

9s is OK for an 8s system, though being slightly narrower than an 8s chain will tend to have slightly shorter life. 10s, is narrower yet, and costlier, with yet shorter life. a 10s chain may also create problems by fitting between the crests of the inner chainring's teeth and the inner face of the outer, an jamming there, or at least failing to drop in smoothly on downshifts (no such problems happen on cassettes).

If you have problems finding them, try searching 8s bicycle chain or the brand + 8s... as in kmc 8s bicycle chain, and you'll fine more choices than you'll know what to do with.

There are small changes in the chainring spacing with 8 speed and 9 or 10 speed cranksets. Running a 8 speed chain on a 10 speed crank would create shifting and other compatibility issues, the outside width of the chain would be too wide for the narrow spacing of the chainrings.

6, 7 and 8 speed cranksets are interchangeable if a 8-speed chain is used. However, 9-speed cranksets run best with 9-speed chains and 10-speed cranksets need 10-speed chains.

You could use a 9-speed crankset, like this: https://www.ebay.com/sch/i.html?_odkw...0+&_sacat=7294

...and be sure to buy a matching Bottom Bracket.

Just use a 9-speed chain with your 8-speed cassette and derailleurs. It will shift and operate well.