Chain slip on middle sprockets

bigmat

I have been having a bit of chain slip on the middle couple of sprockets (running Campag 10 speed) recently. I assumed it was most likely due to chain / cassette wear (they had probably done around 4,000 miles) so I replaced both. On the ride in this morning I had one incidence of the chain slipping when putting the power down riding away from a junction - same sprocket as I had the issue with before changing chain / cassette. Does naybody have any ideas on what the cause of this might be? Pretty sure it isn't the chainring as it only happens in the middle of the cassette. Maybe an indexing issue?

Cheers

Mat

keezx

Campag chains are a bit short when new.
Keep on riding and the problem will disappear.

arlowood

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19778541#p19778541]BigMat[/url] wrote:

I have been having a bit of chain slip on the middle couple of sprockets (running Campag 10 speed) recently. I assumed it was most likely due to chain / cassette wear (they had probably done around 4,000 miles) so I replaced both. On the ride in this morning I had one incidence of the chain slipping when putting the power down riding away from a junction - same sprocket as I had the issue with before changing chain / cassette. Does naybody have any ideas on what the cause of this might be? Pretty sure it isn't the chainring as it only happens in the middle of the cassette. Maybe an indexing issue?

Cheers

Mat

Chain slip/ rough running in the middle of the cassette is often caused by a mis-aligned mech hanger.

Has the bike been dropped/crashed or has it been banged into anything on the drive side recently?

Pop it down to your LBS and ask them to check the hanger alignment or you can buy your own alignment tool and check it yourself

http://www.wiggle.co.uk/lifeline-derailleur-hanger-alignment-tool/?lang=en&curr=GBP&dest=1&sku=5360510136&ci_src=18615224&ci_sku=5360510136uk&utm_source=google&utm_term&utm_campaign=UK_PLA_Accessories&utm_medium=base&utm_content=sKWw8wr8l_dc%7cpcrid%7c71714696822%7cpkw%7c%7cpmt%7c%7cprd%7c5360510136uk

However my guess is that the bike shop will charge you less than the cost of the tool to check it.

bigmat

Its actually a KMC chain (although sold as suitable for Campag). Bent mech hangar could be an explanation - the bike took a series of knocks last year, mech hanger was replaced but then crashed again. LBS bent it back but maybe it isn't completely aligned - will have a look into that thanks. Might just buy a new hanger as always good to have one in as a spare anyway.

veronese68

Good idea to check new hangers anyway. That reminds me, must get my alignment tool back.
Check the chainrings for wear too, although that would of course slip regardless which cog you're on at the back.

bigmat

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19778705#p19778705]Veronese68[/url] wrote:

Good idea to check new hangers anyway. That reminds me, must get my alignment tool back.
Check the chainrings for wear too, although that would have course slip regardless which cog you're on at the back.

Yep, also I changed chainring less than a year ago - should still be OK. New mech hanger ordered, will see if that makes a difference.