![Rear derailleur B-screw does not affect upward limit on guide cog. Cog slams into the cassette with any small drop or bounce on a rock or root. It's very loud, and I Rear derailleur B-screw does not affect upward limit on guide cog. Cog slams into the cassette with any small drop or bounce on a rock or root. It's very loud, and I](https://external-preview.redd.it/DHjNEn5PAYPunuyt2_N2UhJ2m_F6zQsy5Mr6Axhu0Nc.png?width=640&crop=smart&format=pjpg&auto=webp&s=a19a06a9c3672c19c9c0427ccf996888bf8e9070)
Rear derailleur B-screw does not affect upward limit on guide cog. Cog slams into the cassette with any small drop or bounce on a rock or root. It's very loud, and I
![Top-bike Tourney Rear Derailleur RD-TY300 6/7 Speed SGS Direct Mount : Amazon.co.uk: Sports & Outdoors Top-bike Tourney Rear Derailleur RD-TY300 6/7 Speed SGS Direct Mount : Amazon.co.uk: Sports & Outdoors](https://m.media-amazon.com/images/W/IMAGERENDERING_521856-T1/images/I/51pMvmiBkmL._AC_SL1500_.jpg)
Top-bike Tourney Rear Derailleur RD-TY300 6/7 Speed SGS Direct Mount : Amazon.co.uk: Sports & Outdoors
![Mystery adjustment on Shimano Tourney rear derailleur - Is this "B" adjustment or something else? TIA : r/bikewrench Mystery adjustment on Shimano Tourney rear derailleur - Is this "B" adjustment or something else? TIA : r/bikewrench](https://preview.redd.it/yzocx4o947581.jpg?auto=webp&s=a98c07f6550da79049c94f44a3430be1f8681e58)
Mystery adjustment on Shimano Tourney rear derailleur - Is this "B" adjustment or something else? TIA : r/bikewrench
![shimano - Sprocket touching the biggest cog no matter B screw...how do I fix? - Bicycles Stack Exchange shimano - Sprocket touching the biggest cog no matter B screw...how do I fix? - Bicycles Stack Exchange](https://i.stack.imgur.com/XiUmI.png)