The factory installed red, flat thread lifters (7297ER), are optimized for dust pick-up under laboratory conditions, rather than fibre pick-up, as the Ecodesign Regulation specifies 100% dust for the test. However, normal household dirt usually consists of about 50% fibres (from textiles, hair, etc). The brown, rounded thread lifters (7237ER) significantly increase fibre pick-up and reduce pushing force. They will normally give better pick-up in the typical home.
Remove Old Thread Lifters
Remove the red, flat thread lifters by inserting a narrow-bladed screwdriver into the indentations on either side and gently prying up the inserts.
Place New Thread Lifters
Fit the brown, rounded thread lifters in the same place and let them snap into position with a little pressure.