Hi all I have a tech question, here goes I have a home built SWB that has the 105 Deralier set I put on 12 years ago I am now replacing the rear wheel and cassette so I want to know can I go to a 11-36t 10 speed cassette If I do will the 105 beable to shift through all 10 gears if I change out the shifter or is the chain differnt size
The 105 derailleur was made for a 28 tooth maximum and won't have enough capacity for a 36 tooth so there will be shifting problems even if you change out the shifter. If you change the derailleur and shifter you would also need to change the length of the chain for the shifting to work correctly but you can't just add links to an 8 or 9 speed chain. 10 speed sprockets require 10 speed chains. You may find the commentary and information at Sheldon Brown helpful: http://sheldonbrown.com/speeds.html
"it's important to understand what makes them fast. It's more important to understand what keeps them from going faster." DS