Three-cog cassette extender from Absolute Black

by Marc Basiliere 12

Broaden range and save weight with British design..

What's blacker than black?
What’s blacker than black?

With an ever-growing number of cassette range extenders to choose from, it takes something special to stand out.  And something special is just what Absolute Black is offering with this beautifully-machined 4-cog piece.  Designed in England and CNC’d in Poland, the Cassette Adapter 28-40 allows for a range on par with Shimano’s forthcoming XTR group (11-40t), reduced jumps when compared to single-cog extenders, and a weight savings of up to 100g.

Looks shifty...
Looks shifty…

Weighing 50g less than the parts it typically replaces, the Cassette Adapter picks up after a standard 10s 11-34 or 11-36t cassette’s 24, replacing the top three cogs.  Depending on the desired range, one then leaves off the standard cassette’s 11t or 17t cogs.  This makes for 13-40 (308%) or 11-40 (364%) options.  Granted, the former is actually less range than that provided by an 11-34- but Absolute Black pitch the arrangement for anyone looking for lower gears without resorting to a teensy chainring.  The 11-40 makes for a useful broadening over a standard 11-36 (327%), but – as all extenders do – falls a bit short of XX1/Xo1’s 10-42 (420%).

cassette_adapter_ab1Where most cassette extenders add 50g, Absolute Black’s removes that much weight- for a 100g weight saving over the hypothetical alternative.  Given the extra design and manufacturing work required by the 4-cog design and its European manufacture, Absolute Black’s £88/$122/€105 ask seems reasonable.  The 13-40t configuration requires a special lockring which will be provided free to the first 400 purchasers and available separately after that.

Making lockrings desirable
Making lockrings desirable

Available now at

Comments (12)

  1. Ooh that looks great. Top work, good idea

  2. Excellent, this is just what I need.

  3. That looks brilliant, the first (rear?) photo makes it look lovely, sensible price too.

  4. Awesome. Button pressed and ordered – proper useful bit of kit that!

  5. 13-40 avoids the need for a small chain ring

    They are problem because?

    They don’t look cool?

    Are light in weight?

  6. They are problem because?

    Chain wrap at a guess, less chain = more wear and more droppage (that’s an engineering term)?

  7. looks stunning, order button pressed

  8. Can they make a 42T one for those of us with weedier legs?

  9. “reduced jumps when compared to single-cog extenders”
    How exactly?
    You’re still removing a 17t sprocket to make a jump from 15 to 19T right in the middle where you don’t want jumps imo
    Low end is the same: 28-32-36-40t?

    “13-40 avoids the need for a small chain ring”
    Only from the low end*. On the top end, if you had a 32t up front, and an 11t on the rear, with a 13t on the rear, you’d need a 38t up front to give the same top end gear. If you did 38/40 is a higher gear than 32/34 or 32/36

    *but it doesn’t negate the need for a granny ring?
    32t/40t its only equivalent to a 22t/27.5t, or 24t/30t. still around a gear and a half away from 22/34 or 24/36.

    Okay, so it is lighter, and looks better and puts less pressure on an alu. freehub than a single extender.

    I reckon as with single extenders it’d be better if you ditched the 17t AND 15t and replace with a 16t to get a compromise spread rather than a jump

  10. If I’m running a 29er with an 11-36 cassette with a 22/38 chainset, what would be my best chainring if I went 11-40 on the cassette?

  11. James,

    Depending on the crankset, 30t is often as low as one can go- it sounds like some people want a lower range with their existing crankset while maintaining a decent chainline. As far as the need for a granny ring, that will depend on your fitness and local trails.

  12. Made a concious effort on my ride this morning to determine how much I use my 11T sprocket, surprised to find it was only once over 22km. I think I could easily manage without the 11T for trail riding, perhaps only missing it if I needed to do any extended road sections.

    Horses for courses though, depends on the terrain you ride, your fitness, and the cadence you like to pedal at.

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