ychen
New Member
Posts: 1
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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.
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peterb
PBMA Mechanic Member
Posts: 25
First Name: Peter
Last Name: Barson
Location: Chicagoland
Shop / Company: Erik's Deerfield
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Post by peterb on Aug 26, 2016 16:02:01 GMT -6
great tip! thanks
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eileenbrodie
PBMA Mechanic Member
Posts: 13
First Name: Eileen
Last Name: Brodie
Shop / Company: Bob's Cycle Center, Fair Oaks California
Bio: Employed at first shop in 1982. Pursuits include bicycle mechanic, and carpentry/woodworking. Raced road & track, (State Champ silvers), some mtn bike. Worked at: The Bike Shop, Hawaii, Faye & Dennis Saiki. Old Town Bike Shop, Colorado, John Crandall. Tour of Nevada City Bicycle Shop, California, Stan & Marilyn Miller, later Connie & Duane Strawser. Wrench & admin & board member for non-profit Bike Clinic Too, Colorado, preparing bikes for homeless.
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Post by eileenbrodie on Oct 18, 2016 21:18:55 GMT -6
Great initiative tackling this issue. Did Felt have anything to say about it? i.e. did they get feedback from you that might help resolve this at their end in the future? Also, I assume you put the stock rear derailleur back on once you homed in on housing changeout for your solution?
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