Front dérailleur and cable tension
u0362565
Posts: 17
Hi all,
I've trying to get my front derailleur shifts nice and fast and clean. My understanding is that this is achieved by adjusting the tension on the cable using the barrel adjuster. So if the chain struggles to go from the middle chain ring to the largest one then the tension is probably not high enough, solution unscrew the barrel adjuster a bit to increase tension, this will push the derailleur cage further away from the bike frame and thus give the chain a bigger push on to the biggest chain ring. This works nicely now.
The problem now is that changing from middle chain ring down to the smallest is slow or just doesn't happen. I get the feeling that the cable tension is not the issue now as if i change it, it will mess up the adjustment i have just undertaken for the largest ring. So what governs the movement from the middle to lower chainring? Clearly the cage is not moving far enough back towards the frame, but what can i adjust to change that. The limit screws as far as i'm aware are adjusted correctly.
I've trying to get my front derailleur shifts nice and fast and clean. My understanding is that this is achieved by adjusting the tension on the cable using the barrel adjuster. So if the chain struggles to go from the middle chain ring to the largest one then the tension is probably not high enough, solution unscrew the barrel adjuster a bit to increase tension, this will push the derailleur cage further away from the bike frame and thus give the chain a bigger push on to the biggest chain ring. This works nicely now.
The problem now is that changing from middle chain ring down to the smallest is slow or just doesn't happen. I get the feeling that the cable tension is not the issue now as if i change it, it will mess up the adjustment i have just undertaken for the largest ring. So what governs the movement from the middle to lower chainring? Clearly the cage is not moving far enough back towards the frame, but what can i adjust to change that. The limit screws as far as i'm aware are adjusted correctly.
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Comments
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If you add too much tension it won't shift the other way as it's pulled to far out, you need to find the happy medium between the two.
If it shifted down before it won't be the stop screws.
Its easy to get a great shift one way and screw up the other, just keep trying!Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
I think i've managed to sort it now, still changes up through the chain rings well and does now shift down to the smallest chain ring. I actually did change the lower limit screw position as ultimately this does govern how far the cage moves and so now the cage moves back closer to the bike frame taking the chain with it. Weirdly it seems to change through the chain rings more easily when the bike is stationary and inverted compared to riding it, can't fathom why that is, quite frustrating though when you test it inside seems fine then you need to go somewhere and it plays up, unless something is slipping over time.
Thanks0 -
Your drive torque pulls the chain onto the rings, so maybe you need to back off the pedal torque a bit more when shifting at the front (chain under tension side, shifting at the rear the shifting is on the non tension side).Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0
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Also over time the mech can rotate slightly round the seat tube causing problems with shifting0
