Originally Posted by
peteydink
You might see if you could use the Sram Apex derailleur and cassette with your 105. The Apex is 10 speed with up to 11-36.
My LBS has told me that SRAM & Shimano derailleurs are not swappable (if that's a word) back and forth. Must use SRAM shifters with SRAM & Shimano w/ Shimano.
I could be wrong, but I'm pretty sure that Shimano mountain & road derailleurs can be interchanged.