Bicycle Mechanics - Rear Derailleur
Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.
04-20-06, 07:54 PM
I am building a second bike with a triple crank set. It is all ultegra. My question is for my rear deraliier do I have to have a long arm or can i use a standard one.
You need to determine the required amount of chain wrap. This is the number of teeth difference between the big/big and small/small chainring/cog combinations. For example, if you have a 52-42-30 up front, and an 11-25 rear cassette, then your required wrap is (52+25)-(30+11)=36. Your rear derailler must be able to take up 36 teeth. The derailleur should also be rated for the 25 tooth cog.
Now, you can cheat on this if you use discipline and avoid shifting into the big/big and/or small/small combinations. But it's probably best to get the derailleur that is failsafe.
Powered by vBulletin® Version 4.1.12 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.