Grondpad Posted September 17, 2012 Share A buddy of mine has a strange issue where his chain keeps dropping off in front. He has an X7 in front and X9 at the back. He has taken his bike to 3 different stores but it keeps on persisting. What happens is that as soon as he put power on the crank, the chain drops off completely in the front when he is in the middle and small blade. It sometimes happens on the big blade as well but no always. He doesn’t even shift gears, then it just pops of I thought that it might be a worn chain, but wouldn’t that then cause the chain to jump on the cassette rather? I think he is due for a chain replacement anyway, but will this cause the issue in front? Link to comment Share on other sites More sharing options...
divernick Posted September 17, 2012 Share Check the wear on the chainrings and cassette teeth. Measure the chain wear with a chain checker. If the teeth are shark-fin shaped at all, replace. If the chain has more than 1% stretch, replace. Link to comment Share on other sites More sharing options...
George Nel Posted September 17, 2012 Share It might be the spring tension of the rd.Had the same problem on a xx rd,kept dropping the chain.Bought a new rd and problem sorted.Tip when storing bike:always select the small chainring and smallish gear on cluster,that way your rd spring is not under any tension. Edited September 17, 2012 by sam fisher Link to comment Share on other sites More sharing options...
Skylark Posted September 17, 2012 Share Should be one of 2 things - worn chain/blades or damaged FD/incorrect FD settingsI would lean towards worn chain/bladesHe must have taken the bike to 3 rather sh1tty bike shops if they couldn't solve the problem Edited September 17, 2012 by Skylark Link to comment Share on other sites More sharing options...
W3RN3R Posted September 17, 2012 Share Also check the alignment of the hanger bracket for the rear derailer. Link to comment Share on other sites More sharing options...
Hairy Posted September 17, 2012 Share Ok, I am also struggling with the same issue at the moment.Running a new chain and cassetteMiddle and front rings still look very good. Confirmed by a reliable LBS and I also matched it up to new rings, like look just about identical other than a couple of scratchesA riding partner commented on Friday that my hanger looks out of alignment, will get this checked today / tomorrow, but this would make the most sense. Link to comment Share on other sites More sharing options...
Skylark Posted September 17, 2012 Share Ok, I am also struggling with the same issue at the moment.Running a new chain and cassetteMiddle and front rings still look very good. Confirmed by a reliable LBS and I also matched it up to new rings, like look just about identical other than a couple of scratchesA riding partner commented on Friday that my hanger looks out of alignment, will get this checked today / tomorrow, but this would make the most sense. The RD hanger would have to be pretty badly bent to be pulling the chain off the front chainrings - you would know it was bent!!The FD cage must just be parallel to the blades - just look down and eye-sight it , it can be a little bit off , again if its off enough to be pulling the chain off you'll see it.The FD cage height must be 2-3mm above the largest blade Link to comment Share on other sites More sharing options...
Hairy Posted September 17, 2012 Share The RD hanger would have to be pretty badly bent to be pulling the chain off the front chainrings - you would know it was bent!!The FD cage must just be parallel to the blades - just look down and eye-sight it , it can be a little bit off , again if its off enough to be pulling the chain off you'll see it.The FD cage height must be 2-3mm above the largest blade FD = 100%The Chain only jumps under "extreme stress" when mashing really hard in the biggest gearing and racing roadies.I assume the hanger being a bit out of alignment and then when torquing the crank, the bike also flexes and then the combination of the two elements = skip/grinding chain. Link to comment Share on other sites More sharing options...
Skylark Posted September 17, 2012 Share FD = 100%The Chain only jumps under "extreme stress" when mashing really hard in the biggest gearing and racing roadies.I assume the hanger being a bit out of alignment and then when torquing the crank, the bike also flexes and then the combination of the two elements = skip/grinding chain. Sounds like worn blades/chain , I've had what you are describing before and I fiddled and adjusted to my hearts content and nothing would help , new chainrings sorted it out instantly + you will probably need a new chain & maybe also a cassette Link to comment Share on other sites More sharing options...
DR ◣◢ Posted September 17, 2012 Share Is the chain the correct length? Wild shot in the dark. Link to comment Share on other sites More sharing options...
Capcha Posted September 17, 2012 Share Sounds like worn blades/chain , I've had what you are describing before and I fiddled and adjusted to my hearts content and nothing would help , new chainrings sorted it out instantly + you will probably need a new chain & maybe also a cassette+1 blade could have knocked a rock and is slightly out of alignment. Putting power on could drop the chain Link to comment Share on other sites More sharing options...
Hairy Posted September 18, 2012 Share +1 blade could have knocked a rock and is slightly out of alignment. Putting power on could drop the chain The chain and cassette are new.Took the middle a big rings off and they are still good to go.Put a straight edge on the hanger last night and she definitely is bent inwards.Chain length is 100% Link to comment Share on other sites More sharing options...
Hairy Posted September 18, 2012 Share +1 blade could have knocked a rock and is slightly out of alignment. Putting power on could drop the chain The chain and cassette are new.Took the middle a big rings off and they are still good to go.Put a straight edge on the hanger last night and she definitely is bent inwards.Chain length is 100% Link to comment Share on other sites More sharing options...
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