front derailleur not shifint under load

[ivanooze]

so i put a braze on style sram force front der. on my pegoretti, upshifting is ok but my derailleur will not shift down once i start to put certain amount of load on it while climbing. any suggestions?

[OtayBW]

Maybe I'm being naive, but I very seldom have very much load at all when I'm shifting - even when standing during a climb. There's always a way to finesse it in quickly and quietly with a momentary let up of effort. I guess alternatively, if I know I'm going to need to be in the small ring, I'm already there before I need to use the FD during the climb. Maybe I'm not understanding what you're describing.

[MattTuck]

Same with me. I was always taught (and learned from experience) that you do a brief let up to take tension off the chain when you shift. It takes less than half a second...

[thwart]

so i put a braze on style sram force front der. on my pegoretti, upshifting is ok but my derailleur will not shift down once i start to put certain amount of load on it while climbing. any suggestions?
Quick. Do yourself a favor, and delete this before oldpotatoe sees it.

Seriously, from what I know about SRAM FD's, I certainly wouldn't ask it to shift while climbing. I try not to ask that of my Campy FD.

At least not unless I can let up on the pedal force significantly…

[oldpotatoe]

Quick. Do yourself a favor, and delete this before oldpotatoe sees it.

Seriously, from what I know about SRAM FD's, I certainly wouldn't ask it to shift while climbing. I try not to ask that of my Campy FD.

At least not unless I can let up on the pedal force significantly…

Nannynanny already saw it but mentioned above is correct, ease pedal pressure as you shift. Lots of pedal pressure makes top chain segment taught, means less flexible. The 2 systems that don't have a big problem are the electronic groups with really strong, stiff fders and stiff Chainrings. Course the mechanical versions also work really well under load. Only one of the 3 makers has embraced 1by systems.

Another suggestion for the OP, a 6700 front der.

[ontarget]

With heavy tension on the chain (ie: pedaling hard), it's hard for a front derailleur to shift from large to small ring, especially if your large ring has tall teeth and no profiled teeth to assist shifting. After all, it's just the derailleur spring putting tension on the cage, which in turn is putting tension (not much) on a very taught chain.

Like others, I was always taught to 1) Let up a bit when shifting, especially front derailleur and 2) Make the shift in front before actually needing it.

[Fatty]

my derailleur will not shift down once i start to put certain amount of load on it while climbing. any suggestions?

Can I pile on? Yeh, soft pedal. Shifting under pressure is an invite for the dreaded chain-suck.

[lhuerta]

...in addition to the obvious NEVER shift front red under load, u should anticipate needed gearing for climbing conditions and already be in ur small ring to avoid shifting from big to small chainring in middle of a climb

[Cicli]

What everyone else said and........... its sHram, what did you expect? Surely not function, especially when you use it wrong. Maybe ease up a bit?

[ivanooze]

i've always known about the whole chain suck idea, but on my other bike which has a sram rival fd, it rarely happens just as im headed up a climb.
-i've also tested the force fd on flat roads and still does the same thing. It takes quite a while for it to switch...
i guess i just suck at down shifting.

[fogrider]

all the new systems work so well nowadays because of ramped chainrings and flexy chaings but its still not a good idea. think about it, the chain is being moved from one ring to another. with chainrings, you're from a 50 to a 34, a difference of 16 teeth...the difference a lot...enough for the chain to land in the wrong place from time to time. think about it, the shifting of your rd moves the chain up or down a few cogs. back in the day, many riders swear by half step shifting. this is where the chainrings were much closer in size, like 52/44.

[simonov]

i've always known about the whole chain suck idea, but on my other bike which has a sram rival fd, it rarely happens just as im headed up a climb.
-i've also tested the force fd on flat roads and still does the same thing. It takes quite a while for it to switch...
i guess i just suck at down shifting.

If it's not shifting easily on flat roads, where the load is presumably less unless you're trying to shift while hammering, the FD is probably not set up properly or there's another issue. Even a SRAM FD should be able to drop the chain with relative ease. Some potential culprits could be too much cable tension, limit screw not leaving enough room for the cage to move or maybe worn chainrings.

[carpediemracing]

First, unless you have one of a few backwards sprung derailleurs, the front derailleur relies on its spring to move from the big ring to the small ring. Therefore you cannot force it, like you can going from the small to the big.

Since it's spring-based you can only optimize the system. Lowest possible cable friction, tight cage (I don't know SRAM front cages but on all my steel cage Campy front derailleurs I squeeze the front of the derailleur with a set of channel locks, tightening up the front part of the cage, which in turn speeds up shifting both directions).

Also, since the ramps dictate when the chainring wants the chain to move over you should look at where they are and then sort of map them to where you are in the pedal stroke, like "okay when the ramp is coming up to the front derailleur my foot feels like it's here". That's when you should initiate shifts.

For insurance, esp with Campy front derailleurs (for some reason when I drop a chain with a Campy front derailleur I can't pick it up without stopping, with Shimano I can always pick it up), I use a N-Gear Jumpstop on the inside of the small ring. This way I can adjust the derailleur to overshoot the small ring, which means that the spring is free to work the full range of motion, not just until the stop.

Finally you should ease up on the pedals when you shift.

A great way to practice this is to sit on a trainer with relatively high resistance (fluid, mag on higher resistance) and try to shift down while at lower rpms. You can pedal so slowly that a cyclometer barely registers rpm but you should still be able to shift down.

[Birddog]

Now you know why they call it SRAM "Force". Sorry, I had to pile on too. I have a CX bike with SRAM, Force, I hate the way the fron der shifts (poorly). Since their top of the line is "Red", then Force must be puce green.