Setting the B-Gap to the correct distance is as important for the correct functioning of the gears as the correct indexing of the derailleur. How to do it for a Classified cassette:
- Size your chain correctly.
- Adjust the derailleur so that the upper pulley is perfectly under the respective sprocket. For more instructions, check the manual of your groupset manufacturer.
- Shift to the smallest gear (largest sprocket).
- Measure the distance between the upper pulley and the cassette.
- The distance should be 4 mm.
- If the shifting is still noisy or delayed, you may need to check the indexing of your rear derailleur again and adjust it in small increments inwards or outwards.
If that does not solve the issue, it is worth checking our compatiblity chart for the most recent cassette compatibility with different derailleurs.
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