When deciding if my short cage derailleur will take a 12-30 in the rear and a 36-46 up front, I calculate this by capacity of 34T for a 5701 105 short cage rear derailleur by getting the differences of the cassette (in this case 18t) and the chain set up front (in this case 10t) and adding them together to get 28t difference which is acceptable to that rear derailleur, right?
According to United Bicycle Institute:
Determine Maximum Chainring Difference by subracting the number of teeth in the smallest chainring from the number of teeth in the largest chainring
Determine Maximum Cassette Cog Difference by subtracting the number of teeth on the smallest cassette cog from the number of teeth on the largest cassette cog
Determine Total Drivetrain Capacity by adding Maximum Chainring Difference to the Maximum Cassette Cog Difference
Record the Maximum Cassette Cog (the number of teeth on the largest Cassette Cog)
SS - Short Cage Road Double - Maximum Cassette Cog is 27 and Total Capacity is 29
GS - Medium Cage MTB/Road Triple - Maximum Cassette Cog is 34(MTB)/27(Road) and Total Capacity is 33(MTB)/37(Road)
SGS - Long MTB - Maximum Cassette Cog is 34 and Total Capacity is 45
Short - Maximum Cassette Cog is 34(MTB)/28(Road) and Total Capacity is 32(MTB)/31(Road)
Medium - Maximum Cassette Cog is 34 and Total Capacity is 37
Long - Maximum Cassette Cog is 34 and Total Capacity is 45
Short - Maximum Cassette Cog is 26 and Total Capacity is 27
Medium - Maximum Cassette Cog is 29 and Total Capacity is 36
Long - Maximum Cassette Cog is 29 and Total Capacity is 39
Seems the short cage is good for 30T cog and 34T capacitiy. Your 28 teeth is correct and should work fine.
When to use a Long Cage vs Short Cage Derailleur?
By TrailMaker in forum Frame Building
Last Post: 01-21-2012, 06:46 PM
By KK1L in forum Bike and Frame discussion
Last Post: 05-28-2011, 07:11 PM
By juan pablo in forum Wheels and Tires
Last Post: 04-24-2011, 06:37 AM
By Tony777 in forum General Discussion
Last Post: 04-11-2011, 08:28 AM
By schlitzky in forum XC Racing and Training
Last Post: 01-08-2011, 10:15 PM
Can't find it? Just search our site!