Hi,
I want to change my specialized carve comp 29er, from the standard stock shimano Alivo triple crankset to a 9 speed SLX double one http://www.chainreactioncycles.com/Models.aspx?ModelID=28019
I've ordered the above crankset, my question is, what else should I change in order to do a decent job, the current rear cassette is an 11/34 (will this be adequate?), do i need to order a double front mech derailleur? and a double shifter?. Finally why do I keep seeing chain tentioners on double crankset MTB's is this necessary.
Sorry, lots of daft questions from a ham fisted newbie
You can keep everything else the same. You will need to adjust the limit screw on the front mech to stop it from being able to shift into the bash guard...not that you'll do that after a couple of rides. Your rear cassette ratios should be fine too. You don't need new shifters. Unless you currently drop your chain then I wouldn't worry about a chain guide. However you may want to take a few links out of your chain now you won't have the big ring.