Originally Posted by
dirtydozen
I don't quite get the first question, but for the last 2, clearly no i'm not using that 34T cog ever.
Alright thanks for the tip guys. Never thought of putting a 9 speed RD, I thought i could only put 10 speed RD on a 10 speed cassette.
The first question was meant to have you test to see if the RD has the ability to clear the 34T cog.
Do it slowly while in the middle or small chainring just in case the chain was not sized to handle the large/large combo. The RD is rated to 32T with a triple per Shimano's spec and you're only 2T over. Depending on the specific dropout you have, it may have the range to clear the 34T. Additionally, cassettes are a wear item and will need replacement at some point. If you don't need a cassette with a 34T, when you do replace, get something smaller.
Saw your other thread, so after doing the new cable see if the RD can handle the 34T. While you have the cable out, also check the cable housing to verify that the housing ends are cleanly cut and the ferrules aren't damaged.
You may not have to replace the RD at all, especially if you don't use the 34T and don't plan to replace it with the same in the future.