Shimano Ultegra CS-R8101-12 Cassette

Shimano Ultegra CS-R8101-12 Cassette

Leave time behind and master every road profile. The Shimano Ultegra CS-R8101-12 is the benchmark 12-speed road cassette, engineered for riders who demand elite-tier racing performance without compromise. Drawing from the pinnacle technology of Shimano's flagship Dura-Ace range, this cassette features nickel-plated steel sprockets mounted on dual, lightweight aluminium spiders. It delivers an exceptionally stiff, highly responsive platform that handles explosive flat-out sprints and heavy climbing torque with absolute ease.

The standout feature of the CS-R8101 is its implementation of Hyperglide+ technology. Originally developed to conquer extreme mountain bike trails, this technology has been refined for the tarmac. Precision-engineered shifting ramps guide the chain seamlessly up and down the cog cluster. This allows you to shift under maximum load—whether you are pulling a hard turn out of the saddle or clawing up a brutal alpine pass—without catching, skipping, or interrupting your cadence.

Dual-Ratio Options for Every Route

We offer this premium 12-speed Ultegra cassette in two carefully balanced ratios, keeping you perfectly positioned within your sweet-spot cadence:

1. The 11-30T Ratio (Racer & Criterium Spec)

• The Perfect Choice For: Flat-to-rolling terrain, crit racing, and riders who prefer tight, progressive gear jumps to maintain a precise cadence.

• Gear Steps: 11-12-13-14-15-16-17-19-21-24-27-30T

• Why Choose It: Keeps gear steps extremely small in the crucial cruising speeds, allowing you to fine-tune your effort with laser precision.

• Weight: ~291 g

2. The 11-34T Ratio (All-Road & Alpine Spec)

• The Perfect Choice For: High-altitude mountain passes, steep rolling hills, endurance road riding, and gravel excursions.

• Gear Steps: 11-12-13-14-15-17-19-21-24-27-30-34T

• Why Choose It: Gives you an ultra-low gear ratio (often achieving a 1:1 ratio when paired with compact road chainrings) to conquer incredibly steep climbs while maintaining a smooth, non-fatiguing seated pedaling rhythm.

• Weight: ~345 g

Key Technologies

• Hyperglide+ Dual-Direction Shifting: Experience lightning-fast, silent shifts even under full sprint loads or steep-climbing torque.

• Sweet-Spot Gear Steps: Optimised mid-cassette gear steps ensure you can maintain peak pedaling efficiency where it matters most.

• Forward and Backward Compatibility: Designed with a versatile spline profile that fits standard Shimano Road 11-speed freehub bodies as well as modern dedicated 12-speed HG Spline L2 road freehub bodies.

• All-Steel Durability: Solid steel construction across all 12 cogs ensures long-term wear resistance and structural integrity, delivering consistent shifting mile after mile.

Technical Specifications

• Model Series: Ultegra R8100 Series

• Speed Compatibility: 12-speed

• System Type: HG 12-speed (Hyperglide+)

• Spider Arm Construction: 2x Aluminium spider arms

• Sprocket Material: Nickel-plated steel

• Lockring Material: Anodised aluminium

• Compatible Chains: HG 12-speed (e.g., CN-M8100, CN-M9100)

Pros & Cons

• Hyperglide+ technology enables flawless, shudder-free shifts under full load (up and down the cassette)

• High-grade steel sprockets deliver exceptional durability and a longer wear life compared to cassettes utilising soft titanium or aluminium cogs

• Dual compatibility means it fits onto your existing 11-speed wheels as well as newer 12-speed road wheelsets

• Extremely smooth gear transitions prevent sudden cadence drops, especially in the 11-30T configuration

• Slightly heavier than its Dura-Ace sibling, as it uses robust nickel-plated steel rather than exotic, lightweight titanium cogs for the largest gears

• Requires a dedicated 12-speed chain and Hyperglide+ compatible derailleur to unlock the full dual-direction shifting benefit

CS-R8101-12 User Manual

Shimano Warranty

All product warranties are in accordance with the manufacturer's policy (see link in the product details above). In most cases, this is a limited warranty that applies only to the original owner and excludes normal wear and tear, accidental damage, negligence (failure to clean/maintain the product), and improper installation (see User Manual link in the product details above). However, if you experience a problem with the product you purchased from bicyquel _ (original invoice required), please let us know so we can assist you with the appropriate procedure.