My bike was shifting fine but gears 6-8 scraped against the outside of the derailleur. I released the tension cable to adjust the cage to center it on the small chainring, but the L screw isn’t moving the cage at all. Its also a little difficult to manually pull out (end of the video). I’m pretty new at this stuff. From what I’ve seen online I’m thinking maybe its damaged and I need a new one but I’m not sure. Anyone know whats up?
Im following this guide (at around 3:45): https://youtu.be/ZNG7g83lI-s?si=iGz4rOedtHmWHBw3
L-limit screw isn’t moving the front derailleur
byu/LifeBodybuilder4641 inbikewrench
by LifeBodybuilder4641
9 Comments
I would recommend to undo the cable so it has slack and seeing if it moves then to ensure it’s not the cable getting in the way.
It’s possible when you reinstalled the shift cable that you might have put too much tension on it. It can keep the derailleur out enough that the low limit screw isn’t touching anything. If you release the cable, does the the L limit screw move when you adjust it? It’s doubtful you ruined it.
Like others have said it could be the cable tension, but it could also be that your derailleur is hitting the frame, can’t really tell from this angle
The cable is tight and preventing outward movement. Release the cable and ensure the derailleur is moving freely. Adjust limits as close as possible, then reinstall cable.
Don’t adjust limit screws while the cable is attached. It prevents the cage from swinging out to its limits.
After I release the cable, I push the cage by hand to see where the inner and outer plates lie positioned to the chainrings.
i think you know this, but to be precise, the limit screw does not “move” the derailer. it just sets the range within which the derailer can move. if you think of the derailer as moving from left to right, the low limit sets how far left it can swing, and the high limit sets how far right it can swing. screwing in the limits makes that range narrower. so by unscrewing the limit screw as you are in the video, you are increasing how far the derailer can swing to the “left”, that is, further inwards towards the frame.
so am i correct in understanding that you are unscrewing the lower limit screw, and expecting the derailer to swing further inboard?
if the derailer is not moving further inboard, then that indicates that either something is preventing it from swinging further, or it is already at its maximum range of motion.
i can’t imagine anything is blocking the derailer from swinging further inboard, so i suspect that the derailer is already as far inboard as it can get.
with that in mind, i would reassess the situation with the chain rubbing. you say that the chain is rubbing on the OUTSIDE of the derailer in certain high gears. this would in fact have nothing to do with the lower limit screw, since that screw only sets the maximum inbound swing of the derailer.
if the chain is rubbing on the outer edge of the derailer in high gears, you would want the derailer to swing further *outwards*, not inwards. to do that, you would want to increase the cable tension, because the cable is what pulls the derailer. if you need the derailer to go further, you pull the cable more, make sense?
if you tighten the cable, and the derailer still isn’t pulling further, it could be pushing up against the high limit screw; you could try unscrewing it a small amount to see if that fixes it.
importantly, i would not expect the chain to NEVER rub. what you want is a minimum of rubbing when the chain is at extreme cross-combinations (low/high, high/low).
unclamp the cable ❤️
watch some park tool if you need to, too much tension on it if you tightened cable before adjusting
>Im following this guide (at around 3:45):
[https://youtu.be/ZNG7g83ll-s?si=iGz4rOedtHmWHBw3](https://youtu.be/ZNG7g83ll-s?si=iGz4rOedtHmWHBw3)
The video also says at around 3:55 that if the first screw on the inside doesn’t do anything, then the other screw is the L screw. You’re turning the H screw.
The L screw is the lower limit screw, H is the high limit screw. It’s not exactly clear from your photo but this looks like an L to me:
https://preview.redd.it/78nf3nd3btbg1.jpeg?width=1080&format=pjpg&auto=webp&s=1dd5e0e2149358d5f92cd0a855fe976b85a8d95d
Counterintuitively, on my derailleur it was the other screw that was for lower limit.