Excellent cassette adapter for Shimano and Sram users who require that one more extra sprocket on steep climbs. Very simple to install, it fits behind 11-34/36 cassettes, displacing last cluster and one smaller sprocket. It saves on average 50g from your original cassette!


This cassette adapter consists of 28-32-36-40T (154g) sprockets. It replaces your original cluster 28-32-36T (186g). It adds one bigger cog at the end, but still reduce weight and increase stiffness.  You must also take off one more sprocket either 11 or 17T which decreases weight further.


Main advantages of using 4-cog cluster over single 40T cog are three-fold: Greater stiffness as a cluster, alloy freehub safety (15mm vs 4mm base) and huge weight reduction. After-market single 40T cog adds on average 50g to the original cassette, where absoluteBlack cluster takes off 52g. That is 100g difference!

Please note: rider+bike weight limit is 100kg (220lbs). This product is not suitable for shifting under huge loads as it may lead to deformation of teeth.


out of stock. Shipping 8th September. You can backorder.


USA, Canada and RoW Europe customers only UK customers only


Please choose the option which best describes your country. Mistakes will be refunded automatically.

This item can be purchased only on this website for now.


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original XT  11-36T
11 13 15 17 19 21 24 28 32 36 338g
XT 11-36 + absoluteblack_cluster 13 15 17 19 21 24 28 32 36 40 297g
XT 11-36 + absoluteblack_cluster
11 13 15 19 21 24 28 32 36 40 286g
XT 11-36 + 40T Oneup/Wolftooth cog 11 13 15 19 21 24 28 32 36 40 387g

original XT 11-34T

11 13 15 17 19 21 23 26 30 34 316g
XT 11-34 + absoluteblack_cluster 13 15 17 19 21 23 28 32 36 40 292g
XT 11-34 + absoluteblack_cluster 11 13 15 19 21 23 28 32 36 40 281g
XT 11-36 + "General Lee" adapter 11 13 15 17 19 21 24 28 33 40 297g
original Sram PG 1050 11 13 15 17 19 22 25 28 32 36 362g
Sram PG1050 +absoluteblack cluster 11 13 15 19 22 25 28 32 36 40 317g



For running a 1X system, please use medium cage rear derailleur. When in use with 2x10, most recommended is long cage .


Size (Mass +/-1g):





SLX * (CS-HG81-10 11-36), SLX * (CS-HG81 11-34), XT (CS-M771-10 11-36), XT (CS-M771 11-34), Sram ** PG 1050 11-36   10 speed only.


cnc machined 7075 Txxx Aluminum. Monoblock construction


type II anodizing

rear derailleur

must be used with medium or long cage. Medium cage recommended.


Tooth Shape

Heavily optimized for Shimano compatibility

Lockring (optional)

Specially designed 41mm dia. To be used when removing 11T sprocket.




MSRP:  £85 ......

Designed in UK. Manufactured in Poland (EU).


*SLX - this cassette only allows to take off 11T and use a special lockring to lock on 13T sprocket.

**Sram 1050 cassette only allows to take off 15T or 17T. You can't take off 11T as it will result with improper build.



There are two ways to fit cassette adapter to your drivetrain.

Before we start - Always use a new chain with a new cluster. This will increase longevity of drivetrain!


1. Remove the stock 17T sprocket with last cluster from your cassette, then put absoluteBlack cluster on the freehub and mount everything else back. (Sram PG 1050 users- you need to remove 2 spacers in total)

absoluteblack cassette adapter



2. Remove 11T sprocket and last cluster. This option is a lot better in our opinion, but requires special lockring to hold 13T sprocket (lockring is available to purchase on site).  Put few drops of medium strength Loctite on lockring threads before tightening.  This option is only for Shimano cassettes.

absoluteblack cassette adapter


To finish the build off, please do 1-2 full turns(clockwise) of B-tension screw for proper adjustment. No longer bolts required.


If you don't know which option would suit you better, then just go for a ride and observe which of these two sprockets (11 & 17) you will miss less. Study shows, around 90% of mtb riders do not use 11T sprocket in terrain.

Always use correct chain length

*Bypassing the rear derailleur, run the chain around front chainring/largest cog combination. (For the full suspension frame, position the rear suspension for the greatest chain length required. It's usually a normal position where rear shock if fully extended)

*Add 2-4 (start with 4) segments of the chain to this length for proper chain length. (In some cases it may be needed to add 4 links!)


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