Prestacycle

UniBlock PRO Cassette (12 Speed) (Shimano)

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£280.00
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£280.00
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Prestacycle UniBlock Pro 12-speed cassettes deliver smoother shifting, greater freehub engagement and long-term durability through a single-piece design and ARC™ shifting technology. Engineered for maximum compatibility and performance, they reduce wear, improve power transfer and simplify installation across modern and legacy drivetrains.

Features
  • Greater Freehub Engagement, Smoother Operation
    Single-block construction spreads load across the entire freehub in every gear, reducing wear, lowering rolling resistance and protecting high-end alloy freehubs.
  • Spacer-Free Design
    No loose cogs or spacers means faster cleaning, quicker installation and zero risk of incorrect assembly.
  • ARC™ Advanced Radial Curve Shifting Technology
    Optimised tooth profiles deliver fast, smooth, reliable shifting across all major drivetrain systems, including under load.
  • Optimised Tooth Pairing
    Each shift ramp and tooth profile is matched for both upshifts and downshifts to maximise speed and consistency.
  • Wide Gear Range Availability
    Available for Shimano 12-speed road in 11-25, 11-28, 11-30, 11-32, 11-34, 11-36 and 11-40 options.
  • Cross-Freehub Compatibility
    Enables use of one freehub across different drivetrain systems, including HG wheels on Campagnolo setups.
  • Backwards & Future Compatibility
    Supports fitting 11 and 12 speed systems to Shimano 10 speed wheels (with optional lockring) and adapting newer drivetrains to older wheels or trainers.
  • HG12 Freehub Interface
    Compatible with HG12, HG11 and HG10 freehubs. Wider contact surfaces increase engagement despite fewer teeth.
  • Performance Optimised Chain Pairing
    Designed to work with YBN 12-speed chains for fastest, most accurate shifting and lower rolling resistance.
Specifications

11-25T:

Ratios: 11-12-13-14-15-16-17-18-19-21-23-25
Weight: 151 g

11-28T:

Ratios: 11-12-13-14-15-16-18-20-22-24-26-28
Weight: 185 g

11-30T:

Ratios: 11-12-13-14-15-16-17-19-21-24-27-30
Weight: 182 g

11-32T:

Ratios: 11-12-13-14-15-16-17-19-22-25-28-32
Weight: 185 g

11-34T:

Ratios: 11-12-13-14-15-17-19-21-24-27-30-34
Weight: 204 g

11-36T:

Ratios: 11-12-13-14-15-17-19-21-24-28-32-36
Weight: 218 g

11-40T:

Ratios: 11-12-13-15-17-19-21-24-28-32-36-40
Weight: 320 g

Additional Information

— COMPATIBILITY —

  • GEARS: 12 Speed
  • SHIFTING: Shimano
  • YBN 12 speed chains recommended for optimum shifting performance 
  • FREEHUB: Shimano HG11 AND the new HG12!
    (also fits HG10 with our HG10 Lockring, not included)

— PERFORMANCE —

  • Maximum Performance 12 Speed Shifting
  • Interchangeable performance on all Drivetrains
  • Ultra-Strong ChroMoly 3D Structure
  • Ultra-Light – less material needed
  • Larger, better-distributed Freehub engagement
  • Easier to Clean
  • Red alloy locknut included

Installation Notes

Always adjust shifting for any new Cassette

While Tooth gaps and shifting profiles are optimized for all systems, re-adjustment may be necessary. Various brands of freehubs can cause small variations in cassette positioning.

Confirm Compatibility with your derailleur

Not all derailleurs are compatible with all gear ranges. Please verify if your derailleur is compatible with the largest tooth size, and cog gaps that you are ordering. Electronic shifting systems are the most picky about working with gear ranges not offered by the Original Manufacturer.

Note: Shimano 12 speed Di2 recommended gear ratios are 11-30, 11-32 and 11-34. 

Limit screw settings can vary with any cassette / wheel change

DI2 installation instructions may suggest “one full turn” of the limit screws past the limit. We have found this negatively affects the shifting of any brand cassette as it controls the range for each shift. We highly recommend setting the limits screws to offer no-more-than regular free operation of the min/max gears.

Optional Cassette spacer is included

Prestacycle 11 and 12 Speed Cassettes include a 1mm spacer which can optionally be used to move the cassette farther from the spokes. Different wheelsets, different brands of hubs, variations with custom built wheels using different construction, the spacing of the derailleur hanger and many more factors can all determine if the spacer is needed, optional or specifically should not be used.

Reasons to use this spacer:

  • The Chain/derailleur is too close to the spokes when in the largest cog
  • The gear range is outside of the derailleur min/max range
  • Moving the cassette outward improves the bike's chainline
  • Moving the cassette outward makes it more compatible with wheel swaps

Reasons to NOT use this spacer:

  • The spacer pushes the freehub engagement off the end of the freehub
  • The gear range is outside of the derailleur min/max range
  • You are using our optional lockring to put 11/12 speed on a 10 speed wheel
  • The smallest cog is too close to the frame's chainstay or rear dropout
A silver Prestacycle UniBlock PRO 12-speed cassette made of durable ChroMoly steel sits beside a red MG10-12 11T 50N.m lockring on a white background, compatible with Shimano HG12 systems.
The Prestacycle UniBlock PRO 12 speed cassette by Prestacycle, made from tough ChroMoly steel with a honeycomb design, is shown beside a small red component. It’s Shimano HG12 compatible for smooth shifting on a white background.
A round orange badge with a grid pattern, displaying 2023 Bicycling Gear of the Year in bold black and white—perfect for highlighting the Prestacycle UniBlock PRO Cassette (12 Speed) by Prestacycle, Shimano HG12 compatible.
A red metal ChroMoly lockring with notched edges, white “LOCK → 40NM” text, is shown on a white background. Compatible with Shimano HG12 12-speed systems. For use with Prestacycle UniBlock PRO Cassette (12 Speed) by Prestacycle.
A red and white box labeled Prestacycle UniBlock PRO Cassette (12 Speed) (Shimano) sits on a white surface, featuring a clean, modern design and highlighting its durable Chrome Molybdenum alloy construction.

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