A series of questions on idlers:
1) My Tour (recent purchase) has fully-cogged idlers, yet the replacement idler that came as part of an accessory package is non-cogged. What advantage does the cogged idler provide?
2) What specific advantage does the Heavy Duty Idler Wheel kit provide? Does it employ bearings vs. bushings? The photo on the website shows one cogged one smooth wheel; refer to question 1) above.
3) If the Heavy Duty Idler Wheel kit is a distinct advantage, why is it only specified for the front, not the rear?
I ask because sometimes when I'm on a good uphill pull I can feel the vibrations in the frame from individual chain links passing over one of the components in the path. I'm uncertain whether this is one or more of the idlers, the cassette, etc.
Thanks in advance.