I am looking at replacing the drivetrain on my 2007 knoa jake and am having trouble finding an 8 speed derailleur. I have found what i think to be the equivalent to the existing one but it says it is 9 speed compatible and mentions nothing about 8 speed.

Is this also compatible with 8 speed?

http://www.chainreactioncycles.com/Models.aspx?ModelID=19461

If not where can i get one that is?

Cheers

Dan

or this one?
http://www.chainreactioncycles.com/Models.aspx?ModelID=26502

All the indexing is done at the shifter – so there shouldn't be any reason that it won't work

8 speed chains are slightly wider than 9 speed ones.
So a 9 speed mech will be slightly narrower, but it should be ok with 8 speed.

Work fine, it's standard practice to use them now.