Post by ychen on Aug 25, 2016 22:43:26 GMT -6
I work for a pretty big Felt dealer, and recently got a large shipment of VS50s in different colors and sizes. About a good 10-20% of them have a RD shifting inconsistency issue. I spent a good amount of time diagnosing and attempting to fix it. I finally found the solution and here's a small write up about it.
Symptom:
Chain is on the large chainring, and RD cable tension is adjusted properly for smooth shifting up and down. When the chain is dropped to the small ring, the RD tension becomes too high, and will not drop to the smaller sprockets.
If RD tension is adjusted properly while on the little ring, when you shift to the big ring, RD tension becomes too low to go to larger sprockets.
Failed fixes:
The Altus RD spec'd with the bike has too much play at the knuckles. Replaced the RD, shifting improved slightly. But problem still exists.
FD and RD cables possibly crossed inside the downtube. Checked, not the case.
Solution:
Replaced the stock 4mm housing with 5mm housing. Shift cable observed to have slight kink around where it enters the internally routed downtube. Replaced cable as well. Problem fixed.
Symptom:
Chain is on the large chainring, and RD cable tension is adjusted properly for smooth shifting up and down. When the chain is dropped to the small ring, the RD tension becomes too high, and will not drop to the smaller sprockets.
If RD tension is adjusted properly while on the little ring, when you shift to the big ring, RD tension becomes too low to go to larger sprockets.
Failed fixes:
The Altus RD spec'd with the bike has too much play at the knuckles. Replaced the RD, shifting improved slightly. But problem still exists.
FD and RD cables possibly crossed inside the downtube. Checked, not the case.
Solution:
Replaced the stock 4mm housing with 5mm housing. Shift cable observed to have slight kink around where it enters the internally routed downtube. Replaced cable as well. Problem fixed.
