As the title says, the high limit screw on my front derailleur is preventing shifting up to the largest chainring, while on the largest rear cog. When on the smallest rear cog, the FD shifts no problem when its H-Limit screw is correctly set.
The housing and cable are brand new. I also have a new rear 105 derailleur, new cassette and a new 10-speed Shimano chain. The front derailleur is a Shimano 105 FD-5700. I believe the height and angle are set correctly, at least according to Shimano’s instructions. There is around a 3mm gap and the cage is parallel with the largest chainring.
What I did to adjust the derailleur:
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With tension cable disconnected, set the L-limit screw so there was around a 0.5mm gap between the inner plate and the chain, as per Shimano’s instructions.
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Attached the tension cable. At this point, while on the largest cog in the rear, it was able to shift to the larger chainring. It shifted smoothly back down the smallest chainring as well.
In the video, I already have the H-limit screw set correctly according to the instructions and it will not shift up. When I was actually adjusting it, I was able to ensure it smoothly shifted but this only worked with the H-Limit screw backed out (counterclockwise). -
Shifted to the smallest rear cog, shifted up to largest chainring and set the H-Limit so there is a ~1mm gap between the outer plate and the chain. While remaining on the smallest rear cog, it can shift up and down between the two chainrings without issue.
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After shifting back to the smallest chainring and largest rear cog, as you can see in the beginning of the video, it won’t shift to the larger chainring. The only way to allow it to shift to the largest chainring is by loosening the H-Limit screw (as I did in the video), to the point where it will sometimes throw the chain off when shifting to the largest chainring.
It was a little hard to film, so I apologize if the video isn’t all that helpful.
Is anyone able to identify where I am going wrong? I’ve had success adjusting front derailleurs before, so I’m unsure what I’m missing.
H-Limit screw preventing FD from shifting
byu/mb_7171 inbikewrench
by mb_7171
6 Comments
Two theories at this time.
1:
> I’ve had success adjusting front derailleurs before, so I’m unsure what I’m missing.
~~What directions did you follow? The toggle-link FDs do NOT get set up like traditional FDs.~~ EDIT: My bad. Me no read.
2:
How did you size the chain?
Let’s see the rear derailleur in big:big to confirm.
I had the same issue setting up Tiagra 4700. These new FDs don’t work the way you would think. Read and follow the Shimano papers, you probably need to flip that stupid little toggle pin too.
It’s worth the extra pain, they shift way better than the nine speed ones.
Check out the park tool video on front derailleur setup – it’s amazing, front derailleurs can be really frustrating to setup as one little adjustment can throw the whole thing off.
The gear you’re trying to shift to is called “big-big”. It isn’t a gear that is ever recommended to be in, as it causes too much stress on the chain. The large angle it creates is what is making it difficult to shift.
You should watch some Park Tool vids on YouTube.
The fd low limit is set in the lowest(largest) cassette gear, and the fd high limit is set in the highest(smallest) cassette gear.
If going to the most extreme cross-chaining combo possible is your only issue, I’d stop troubleshooting 😉
Sometimes reading the manual doesnt work,
after installing everything, turn the barrel adjuster so it is centered on its range,
then set the lower limit screw a bit too tight,
then install the cable,
and then loosen the L screw a bit.
And then when you are on the highest gear (large chainring, smallest cassette cog) adjust the H limit screw so there is about 1.5mm of space between the cage and the chain, and then loosen it just a quarter turn.
Then use your barrel adjuster to allow you to push the large lever on your shifter with a normal amount of force (similar to the force you apply when shifting from lets say 8th gear to 4th gear at the back, not a typo, I’m saying multiple upshifts)
You dont need tension to switch to smaller chainring, you need the limit screw to prevent your chain dropping. In other words, even without the front shifter cable, you should be able to ride your bike on the small chainring without worries.
You need tension (thus the cable) to put your chain into the larger chainring, and if you tension it too much, you will fight against the H limit screw to make the shiftwr click.
Limit screws are not to stop your shifters from releasing/pulling cable, they are there in case shit hits the fan, they limit the derailleur from going too far that the chain drops. Barrel adjusters deal with the indexing and tensioning the cable correctly.
Sometimes you really dont need the manual 😁
Edit: forgot to add, I have a 105 5800 series fd and its such a pain to adjust as well but this way it works perfect, no chain drops since I started to set it myself (basically the first service after it got its first scratch 😀 until then, it felt too nice/fancy to risk messing it on my own)