Originally Posted by Ranger
Of course their are quality differences in between upper and lower end derailleurs but they are small. And they make no detectable difference in shifting if you ask me. For what it's worth, i've shifted a few thousand times so i probably know.
I expect my LX and XT derailleurs will last longer. I hope they do because they cost more. But not once have i ever noticed that they shifted better, than Alivio or Acera when all adjustments were proper.
For the most part I agree that if tuned properly most equipment will function as intended. But the real truth is that low-end components never will or are they even expected to function like C Record or Dura Ace parts.
A non-indexed Suntour system while light and bombproof just won’t shift as fast as an XT system no matter how well you tune it. Partly in that you need to focus more attention to shift a non indexed system.
Non-profiled cogs shift louder and slower than smooth surfaced profiled shift aligned cassettes. And low-end rings will not shift under load no matter how perfectly they are adjusted.
On the road, a one second shift is acceptable to some I suppose, but on the trail a sub one-second double shift (rings and cog) is often required, and being able to make that shift under load often can make the difference between cleaning a section and dabbing.