DR ◣◢ Posted July 13, 2020 Share hmm.... So here is my 2c..... Sometimes when getting into the big gears under load, the chain pulls the rd ever so slightly in towards the frame, so the swing arc is a fraction of a MM closer to the cogs when shifting. This means that any debris (or just the chain) tends to catch the bigger gear ever so slightly before the derailleur moves 'down' in it's arc. I don't run dish plates on the back of my bikes, but have had to fix many. Crunching usually means that the top jockey wheel needs to be set ever so slightly away from the cassette or the tension needs to be half a barrel turn less. Or both. But without seeing it that is just going on past crunchy noises of my mates with big gears I will be checking that out, thank you. Link to comment Share on other sites More sharing options...
DieselnDust Posted July 13, 2020 Share Crunchy grindy noise. Hmmmmmmm, Are you sure the chain isn’t a link too short?Can you a side pic of with the chain on the 50t sprocket. What to see the angle of the jockey pulley cage Link to comment Share on other sites More sharing options...
DR ◣◢ Posted July 13, 2020 Share Hmmmmmmm, Are you sure the chain isn’t a link too short?Can you a side pic of with the chain on the 50t sprocket. What to see the angle of the jockey pulley cage I used the Shimano guide for the chain length and the position of the top wheel when setting the b-screw DieselnDust 1 Link to comment Share on other sites More sharing options...
TheoG Posted July 13, 2020 Share Are you able to back pedal without the chain dropping a gear or two? Maybe your chain-line from the front chain-ring needs to be "adjusted/moved" towards the frame, in other words the chain angle is simply to big when on the 51T ... I had this issue, luckily I could mount my front chain-ring on the inside of the crank spider and solved the issue 100%. Mongoose! 1 Link to comment Share on other sites More sharing options...
Mongoose! Posted July 13, 2020 Share getting the chain line 100% is a fine art ja... Link to comment Share on other sites More sharing options...
DR ◣◢ Posted July 13, 2020 Share The crank can't be spaced closer to the frame. Already at the limit of what is possible. It's definitely not a chain line problem. It does climb down when I pedal backwards but only when in 51 and whatever sits next to it. Takes quite a few pedals before it climbs down. Link to comment Share on other sites More sharing options...
Mongoose! Posted July 13, 2020 Share The crank can't be spaced closer to the frame. Maybe send us a picture of your chain line when on 51t Link to comment Share on other sites More sharing options...
DieselnDust Posted July 13, 2020 Share I used the Shimano guide for the chain length and the position of the top wheel when setting the b-screw Background.jpg Ok that setting looks perfect.Now with you sitting on it as the chain growth could be pulling the derailleur too close to the cassette. in the 50t please. PS: flippen nice bike! Edited July 13, 2020 by DieselnDust Jewbacca 1 Link to comment Share on other sites More sharing options...
DR ◣◢ Posted July 13, 2020 Share Ok that setting looks perfect.Now with you sitting on it as the chain growth could be pulling the derailleur too close to the cassette. in the 50t please. PS: flippen nice bike! Thanks man. Appreciate it. The crunching starts in the 3rd gear from the top. I believe that piece is separate from the rest of the cassette. I made some adjustments last night and this morning. Just busy with work before I can go test it. DieselnDust 1 Link to comment Share on other sites More sharing options...
TheoG Posted July 13, 2020 Share I didn't like the Sunrace cassette, its heavy and just appear cheap, replaced mine with a Garbaruk, weight and quality far superior, granted at a cost ... It's quite possible that something worked itself loose on that last three gear "cluster". Link to comment Share on other sites More sharing options...
DR ◣◢ Posted July 13, 2020 Share I didn't like the Sunrace cassette, its heavy and just appear cheap, replaced mine with a Garbaruk, weight and quality far superior, granted at a cost ... It's quite possible that something worked itself loose on that last three gear "cluster". It's a cassette with 80km on it. I checked everything and it's rock solid. I'm still convinced it's an adjustment. Link to comment Share on other sites More sharing options...
TheoG Posted July 13, 2020 Share Actually the last 4 is one piece. Link to comment Share on other sites More sharing options...
Jewbacca Posted July 13, 2020 Share Ok that setting looks perfect.Now with you sitting on it as the chain growth could be pulling the derailleur too close to the cassette. in the 50t please. PS: flippen nice bike!Thats exactly what I think it is...... DieselnDust 1 Link to comment Share on other sites More sharing options...
DR ◣◢ Posted July 13, 2020 Share Looks like the b-tension adjustment made the difference. Double checked everything and slapped on a fresh coat of lube. Had to drag the brakes to put maximum power down on the chain and it was dead quiet. Thank you to all the people that contributed to the thread. Really appreciate it. All this new tech has this old man shaking his head. Jewbacca and DieselnDust 2 Link to comment Share on other sites More sharing options...
Mongoose! Posted July 13, 2020 Share What I've done so far. - B Tension is 100% correct lining up the teeth on the cassette with the line on the derailleur cage glad you sorted now Link to comment Share on other sites More sharing options...
CARANXCycleMobile Posted July 13, 2020 Share Are you certain the hanger is straight?Sounds like a hanger mis-allignment..Top gears usualy showing you that, chain rubbing on the next gearing or jumping around if hanger is bent more.Also check the b-screw setting,the deraileur cage inside has a 51T advised setting indicator mark where the teeth should be alligned"set in the top gear"and view it from the non driveside side.Hope this somewhat helps Link to comment Share on other sites More sharing options...
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