Extralite pulley wheels have been evolved to a greater degree
Rolling resistance is further reduced by custom-developed ceramic bearings.
Each pulley wheel features a twin bearings assembly for unmatched stability and shifting precision.
Pulley body and teeth are 3d machined from self-lubing and highly durable polymer.
Extremely light and tricky.
What are the advantages?
Two paired bearings on each pulley stabilize the lateral play virtually eliminating any left-to-right play (similarly to a front wheel-hub).
A single-bearing pulley can't even get close to this level of lateral stability.
Friction: apparently more bearings would increase the overall friction but actually that's not the case.
Thanks to the vastly improved rotating geometry described above the bearing size can be minimized to the point where
the much smaller difference between inner and outer races reduces ball rotation friction way under the 50% of the single-bigger-bearing generally employed on derailleur pulleys.
The use of custom-made HDC precision ceramic bearings further enhances the quality of the UltraPulley rotating system, allowing the lowest friction factors in the bike-tuning industry.
Most derailleur cages can fit a pulley with 1 or 2 more teeth than the original.
Pulleys with phased teeth (PH) can be applied also on standard double chainring systems with the benefit of a higher shifting precision.
In fact, phased pulleys were born to help guide the chain on MTB single chainring systems.
Basically wider pulleys can be mounted on nearly any derailleur.
For example, Durace has been positively tested with 12-12PH , 12-14PH and 13-13.
However, each setup differs slightly so you always have to analyze it specifically
In case of doubt simply check how much clearance your current pulley has.
Note the diameter changes between these common teeth counts:
- 12T PH=50mm
- 14T PH=59mm
If you plan to fit UltraPulley 12-14PH note that 12PH behaves differently and more precisely than a regular 12.
In the case of UltraPulley 13-13 teeth are not phased however the wider diameter brings the upper pulley a bit closer to cogs and that may add precision in some systems too.
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 test and try.
Stability and Friction - Rotation System
UltraPulley (all models) feature the most advanced spinning system currently in use.
The system is based on 2 paired-micro-ceramic-bearings on each pulley instead of one bearing per pulley as most others.
Weight: see table below
Sealing: low friction 2RS seals
Construction: twin bearing system
Bearings: 4 Precision Ceramic Bearings
Material: self-lubing hi-tech polymer, alloy inserts
Compatibility: see table below