HOW CAN I TELL MY DERAILLEUR PULLEYS ARE WORN OUT?
The bearings are easy to spot. Remove the pulley covers and spin the bearing between your fingers. If they feel rough or gritty, they need to be serviced. If the service does not solve the issues, that is an indication the bearings are worn.
The wheels will show wear and tear over time as well. As they wear down, chain retention will be less and shifting will become vague. Inspect the wheels regularly and if you see the teeth changed shape or start to look pointy, replace them.
HOW HARD IS TO REPLACE DERAILLEUR PULLEYS?
This job is pretty straight forward on any stock derailleur by Shimano, Sram or Campagnolo. A single allen key can do the job.
After replacing the pulleys, you might have to adjust the cable tension. If you upgraded to larger pulley size, check the angle adjustment or B-tension screw settings as well as the chain length if it is still appropriate for your new setup.
HOW MUCH DO BIKE SHOPS CHARGE TO INSTALL DERAILLEUR PULLEYS
The hourly rate varies from one shop to the next, mostly based on their expenses for real estate and the cost of finding good mechanics in the area. For this reason, it is hard to put an exact dollar amount on the procedure. It would be reasonable to expect an installation to take around 15 minutes, so a quarter of your local shop’s hourly rate is a good benchmark.
WILL I NOTICE ANY DIFFERENCE IN PERFORMANCE (WHY NOT JUST REPLACE WITH A STOCK DERAILLEUR PULLEYS)?
Derailleur pulleys are the fastest spinning parts on a bicycle. It makes total sense to optimize them. Since Kogel uses a hard aluminum for our pulley wheels instead of plastics, you will notice they will not wear as quickly as stock pulleys. This is specifically helpful for off road use.
ARE DERAILLEUR PULLEYS MEANT TO BE REPLACED?
Yes, derailleur pulleys are wear items, just like chains and tires.