Chain grinding sprocket under heavy load

Oskik330i
Oskik330i Posts: 6
edited March 2021 in MTB workshop & tech
Good evening for all, I'm new to this forum, so much info here wow !

But my bike have a problem i try to sort it all Saturday but unsuccessful.
Current system on my bike 1x11 SLX with XT rear derailleur. Under heavy load my chain making grinding noise, i believe chain rubs against side of the next upper sprocket. It only happens on second and third cog from the top largest one.
I check everything is tight, what it can be ?

https://ibb.co/XbBYyLf

Comments

  • mully79
    mully79 Posts: 904
    Check b tension screw which sets the distance between the upper derrailieur cog and the cassette.
  • Oskik330i
    Oskik330i Posts: 6
    mully79 said:

    Check b tension screw which sets the distance between the upper derrailieur cog and the cassette.

    I think my b screw on perfect setting now, it happens when pedal , not when shifting
  • mully79
    mully79 Posts: 904
    B tension is a bodge on 1x drivetrains so don’t be too confident on perfection.

    I find single ring drivetrains do grind. Especially the front chain ring which sounds like it’s grinding to death if you pedal through a muddy puddle.
  • steve_sordy
    steve_sordy Posts: 2,453
    edited March 2021
    Is the chain line correct? If the front ring is further away from the centreline of the bike than it should be, the chain can be at a more acute angle to the big gears, causing the scraping noise. When I converted a bike from 2x10 to 1x12, I had to use some extra spacers tom get the chain line where I needed it to be.

    Have you checked the bolts on the non-drive side crank that they are holding the crank in place relative to the bike. Depending upon your crank, if the non-drive side comes loose, the drive side can move outwards. I'm not an expert on different cranks, but this happened to me once and that was the cause.
  • Oskik330i
    Oskik330i Posts: 6
    edited March 2021
    On Saturday I've reinstall cranks and bb but all was tight and good . I moved 2mm bb spacer to non drive side so now my cranks more in center and chain line looks better when shifting up and down.
    Any chance my frame not compatible to 11 speed gears cube analog 2018 i upgraded from 9 speed ? Flexes to much ? Rear axle quick release 9mm.

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