Shimano Ultegra CS-6700 Cassette – 10-Speed, 12-30T, HG Freehub
The Shimano Ultegra CS-6700 12-30T cassette is a wide-range 10-speed option designed for riders who need lower climbing gears without moving to a compact drivetrain change. It maintains smooth Shimano shifting while adding a bailout gear for steeper terrain.
Key Functional Details
- 10-speed road cassette with extended 12-30T range
- Provides lower climbing gear compared to 11-28T setups
- Compatible with Shimano HG freehub bodies
- Designed for consistent, reliable shifting under load
- Durable steel cogs for long service life
- Ideal for endurance riders and hilly terrain
Technical Specifications
| Brand | Shimano |
| Model | Ultegra CS-6700 |
| Speeds | 10-speed |
| Gear Range | 12-30T |
| Cog Sizes | 12-13-14-15-17-19-21-24-27-30 |
| Freehub Compatibility | Shimano HG (Hyperglide) |
| Material | Steel cogs |
| Weight | 245g |
| Color | Silver |
| UPC | 689228299726 |
Compatibility & Technical Notes
Good Fit:
- Shimano 10-speed road drivetrains (Ultegra, 105, Tiagra 10-speed)
- Shimano HG freehub bodies
- Riders needing lower gearing for climbing or loaded riding
- Compact cranksets (50/34) for extended range setups
Not A Fit:
- 11-speed or 12-speed drivetrains (spacing mismatch)
- Short cage derailleurs not rated for 30T max cog
- SRAM XD/XDR or Shimano MicroSpline freehubs
This cassette may require a medium cage rear derailleur depending on your drivetrain setup and chain capacity.
Service / Ownership Context
Installation requires a cassette lockring tool and chain whip. Always check derailleur capacity before installing a 30T cassette. Pairing with a fresh 10-speed chain is recommended to ensure proper shifting and prevent skipping.
Fit & Use Signals
- Best for riders tackling steep climbs or long endurance rides
- Ideal for older 10-speed bikes needing easier gearing
- Good option for touring or loaded riding setups
- Less top-end speed than 11T cassettes but improved climbing ability
Biggest issue here is derailleur compatibility—many older short cage road derailleurs max out at 28T. A 30T will often require a medium cage derailleur or a hanger extension. Customers will also notice the loss of the 11T top gear—important if they ride fast group rides. Always recommend checking total drivetrain capacity (chain wrap). As always, install with a new chain—10-speed systems are sensitive to wear mismatch. This is a great “save the knees” upgrade for aging drivetrains without changing cranksets.