Proflex 856+9 Speed cassette

[Ricky]

I have a Proflex 856. I brought new wheels which comes with an 9 speed cassette, will it fit on my bike?

[Simon]

Your wheel will fit as 8/9 speed cassettes are interchangable,but if your running with 8 sp shifters you will need to change to a 9 sp one plus a 9sp chain and 9sp front chainrings if you do not already have them fitted,there can be cases where you may need to replace the front and rear mechs also,there is a 9sp compatibility article in the files section,your best bet is to probably change the 9sp cassette to the 8sp one from your old wheel that your replacing,
Simon.

[Matno]

Like Simon says, the fit isn't a problem - it's the compatibility with the rest of your drivetrain that is the problem. If you go to a 9 speed setup, here's what you can change:

Bare minimum changes (i.e. MUST change):
Rear (right) shifter (your 8 speed shifter will NOT work because the spacing is different between gears)
Rear derailleur (if your new 9 speed cassette has a bigger biggest ring than your old derailleur can handle)
Chain (9 speed chains are narrower. An 8 speed chain will ghostshift all over the place on a 9 speed cassette)

Probably need to change:
Front derailleur may need to be changed (depending on your shifters and whether they allow you to "trim" your shifts like some grip shifters do).

Don't need to change:
Front shifter (unless you want to match the rear one)
Chainrings (the 9 speed ones are spaced the same. They are slightly thinner, but that serves no real functional purpose other than to maybe shave a couple of grams, and the 8 speed rings are stronger).

[Carbon_Angus]

I'd just swap back to an 8 speed cassette and you will be good to go.

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