UltraPulley Tuning
Upgrade your derailleur
Most derailleur cages can fit pulleys with one or more teeth than the original.
However each setup differs slightly so you always have to analyze it specifically.
As example Dura Ace 12s (and 11s) have been positively tested also with 13-13T, 12-12PH and 12-14PH
The possible improvements are part of your personal taste and tuning process, no written rules to project your ideal setup.
Tuning Notes
Basically wider pulleys can be mounted on nearly any derailleur.
Originally phased-pulleys were born to help guiding the chain on MTB single chainring systems but can fit well road systems too.
Pulleys with phased teeth (PH / PHB) can be applied also on double chainring systems with the benefit of a higher shifting precision at the cogs.
As example if you plan to fit UltraPulley 12 Phased in the upper position note that it behaves differently and more precisely than a regular 12T (non phased).
Alternatively consider UltraPulley 13T that's not phased but its wider diameter keeps the upper pulley a bit closer to cogs and that may add precision in some setups too
Each setup differs slightly so you always have to analyze it specifically.
Clearance
IWhen in doubt simply check how much clearance your current pulley has.
Note how the diameter changes between these common teeth counts:
- 11T= 42mm
- 12T= 50-52mm
- 13T= 56mm
- 14T= 59mm
These simple examples may help you to project your setup but the kind of possible improvements are part of a personal tuning process and taste.
Check your parts and try!