Front derailleur adjustment

raymond82

I'm trying to adjust my front derailleur but it doesn't seem to work...

First it worked fine on the bike stand but when I took the bike out it wouldn't shit to the largest chainring. Then I redid everything, now it's shifting fine on the bike stand when the chain is on the smallest cog but when I put the chain on one of the middle cogs it doesn't work anymore ... Any idea what could cause this?

It's a 46/36 Sram apex crankset with a 2010 Sram force FD and 2008 rival shifters, maybe it's an incompatibility issue? I'm going crazy, it shouldn't be too hard to install a FD right?

raymond82

I should also say that it's a bit difficult to move the FD, when I pull the cable the RD moves easily but if I do the same with the FD cable it takes quite a lot of strength to move it. Is that normal?

farrina

raymond82 wrote:

I should also say that it's a bit difficult to move the FD, when I pull the cable the RD moves easily but if I do the same with the FD cable it takes quite a lot of strength to move it. Is that normal?

I would say not. It may be that you need to replace the cables,

Try disconnecting the cable from the front mech entirely and moving the front mech it by hand to see if it moves smoothly.

My only other thought is that you check the manufacturers instructions to make sure the cables are correctly routed.

raymond82

Thanks for your reply! The inner cable is brand new, the outer cables I replaced about a month ago. I took the FD off and also without cable it takes quite some effort to move it. It moves smoothly but it feels as if the spring is just very tense. It cannot be an incompatibility issue right?

With the limit screws set appropriately I had to put a lot of tension on the cable and still it wouldn't shift to the larges chainring.

skyd0g

It sounds like you may have too much tension in the cable. Check here for adjustments & set-up.
http://www.parktool.com/blog/repair-help/front-derailleur-adjustments

raymond82

I took the FD to a bikeshop today and they told me that the tension was normal. He did say that the limit screws didn't look right so I just redid the whole installation starting off with the limit screws completely loose. It seems to work now, although I have to hold the shifting lever for a while for the chain to move but I guess that's normal. I thought I followed the instructions on limit screws but I guess I screwed up somewhere...

It sounds like you may have too much tension in the cable. Check here for adjustments & set-up.
http://www.parktool.com/blog/repair-hel ... djustments

Cable tension is much less now after setting it up again. Thanks for the link, I usually end up on random sites whenever I need to fix semething but it's much better to have everything in one place.

raymond82

Just for closure on this thread, I think in the end the problem was the limit screw. I sat down and reasoned for a while and realized that tightening the cable in order to make it shift to the big ring is pointless if the limit screws stops the front mech. So instead of setting the limit screw such that it was ~ 1 mm from the big ring, now I set it such that the chain doesn't fall off when upshifting. Now it shifts like a dream on the bikestand, on the road I would still wish it was smoother but at least it shifts reliably.

patrickf

It might also be worth checking the cable routing especially just behind the cable bolt on the FD.

The cable should run over the top of the notch behind the bolt.

This seems quite a common problem with SRAM FDs.

I see no reason why your components wouldn't be compatible.

raymond82

The cable should run over the top of the notch behind the bolt.

I wasn't sure what you meant so I had a close look at the bolt and then I noticed that the mech is quite damaged where the bolt fits (see pic). Also I remembered that I once lost the bolt and now I'm using an old Shimano one. Cconsidering that I think that the cable is not fixed like it's meant to. Could that be what's causing the difficulty in shifting?

desweller

Front derailleurs can be a bit vulnerable to contaminants making their way into their pivot bearings. They're pretty basic though, so you can do a pretty effective job of flushing them through with WD40 while waggling the mech through its range a few time (think 30 to 60 seconds of this), then running some heavier oil into it for lubrication in operation.

raymond82

I already cleaned it quite thoroughly with the typical lemon degreaser but I didn't lube it yet. It's true there's quite some tension on the springs but it runs smoothly. I'll lube it and then I have to keep messing around with the adjustments I guess, I'm still not completely satisfied with the shifting.

raymond82

I should explain why I'm annoyed by not getting the shifting right, I used to have a 42t outer chainring but shifting was always crappy as hell. I bought the 36/46 crankset because I thought shifting would work better with a larger chainring, as front mechs are not really designed for shifting 34/42. That's why I'm not stopping until I have very smooth shifting...

I just worked on the bike a bit more, I noticed that if I shift manually by pulling the cable by hand it shifts nicely but when I use the levers it doesn't work that well. Earlier in this thread I thought it was because of the limit screws preventing the mech from moving outwards enough but I can discard that theory I guess, first of all because the chain would fall off with the limit screw loosened and second because I can shift with the limit screw tightened when doing it manually. Leaves me with the cable and the way it's attached to the mech, I think I'll get a new cable tomorrow as this one might be a bit worn from all the loosening and tightening I've been doing the last couple of days.

Also when the chain is on the smallest cog, then it works really well but when it's one one of the middle cogs it's much more difficult...

pilot_pete

Where it clamps doesn't look to healthy in your photo... Could affect the pull if not clamping properly, or at the wrong angle due to the worn parts I suppose.

PP

raymond82

Ok, I guess I should go try a new mech then. I read here and there that Sram front mechs don't shift too well in general, at least worse than Shimano ones. Shimano ones have a narrower cage it seems, I think I'll try picking up a second hand one to see if it works better.

patrickf

raymond82 wrote:

The cable should run over the top of the notch behind the bolt.

I wasn't sure what you meant so I had a close look at the bolt and then I noticed that the mech is quite damaged where the bolt fits (see pic). Also I remembered that I once lost the bolt and now I'm using an old Shimano one. Cconsidering that I think that the cable is not fixed like it's meant to. Could that be what's causing the difficulty in shifting?

That's the bit where your cable needs to go over. The cable does have a tendency to want to slip under that both though as you tighten the bolt so keep an eye out for that. It does look like there's some abrasion in between the bolt and the notch - perhaps a sign that the cable was routed wrong?

Your bolt also has a little plate on it - I don't think my SRAM FD has that. I'll double check later though.

As mentioned further down the clamping area does look a bit iffy but it should still shift well. I presume the FD is clean and moves easily by hand?

patrickf

raymond82 wrote:

Ok, I guess I should go try a new mech then. I read here and there that Sram front mechs don't shift too well in general, at least worse than Shimano ones. Shimano ones have a narrower cage it seems, I think I'll try picking up a second hand one to see if it works better.

That's a load of rubbish. My Rival FD shifted like a pig when I first installed it. I then found that the cable wasn't routed properly and once I corrected that it shifts *really* easily. I will bet that people complaining about their FD not shifting properly just haven't got it set up properly.

raymond82

That's a load of rubbish.

Ok, thanks for clarifying that!

I've always routed the cable to the inside of the notch, exactly where the abbrasion is visible. With routing it over the notch, you mean in the way I drew it in green? I can't see it too clearly in the user manual.

The bolt has a little plate cause I once lost the original one, this one if from an old Shimano derailleur. Otherwise the FD is clean, I takes effort to move cause the spring is tight but it moves smoothly.

patrickf

raymond82 wrote:

That's a load of rubbish.

Ok, thanks for clarifying that!

I've always routed the cable to the inside of the notch, exactly where the abbrasion is visible. With routing it over the notch, you mean in the way I drew it in green? I can't see it too clearly in the user manual.

The bolt has a little plate cause I once lost the original one, this one if from an old Shimano derailleur. Otherwise the FD is clean, I takes effort to move cause the spring is tight but it moves smoothly.

That's exactly how I mean. Try it - you'll be amazed at the difference it makes. When I first had the cable routed the way you had, it was really difficult to shift from the small ring to the big ring.

I've also had a look at the bolt on my Rival FD and it has a flat round washer (fairly thick) under the bolt head. I suspect you should be fine with the Shimano one as long as it sits right and doesn't get int he way.

Oh, the manual is rubbish too. You're quite right, it doesn't show it clearly at all and is why I also got it wrong to start with.

hstiles

I had a Planet X Pro Carbon with Rival groupset. Front shifting was very smooth, but I discovered pretty quickly that SRAM is very sensitive to how front and rear derailleur cables are routed.

raymond82

That's exactly how I mean. Try it - you'll be amazed at the difference it makes.

I tried and I really think its working better now!! Tomorrow I'll take it out for a ride to see how it functions on the road but on the bikestand it sure runs smoother. It also looks better, more solid. I do have to change the cable because from all the loosening and tightening it got worn exactly where it passes the notch. I reversed the washer so the little plates stick out to the other side so they're not in the way.

I had a Planet X Pro Carbon with Rival groupset. Front shifting was very smooth, but I discovered pretty quickly that SRAM is very sensitive to how front and rear derailleur cables are routed.

When I first had the cable routed the way you had, it was really difficult to shift from the small ring to the big ring.

I've had trouble with the front mech since the day I installed it but I always thought it was because of running the unusually small 42t outer chainring because I couldn't get the mech as low as it should be.

I'll let you know how it's going tomorrow after I test it but thanks a lot already!

raymond82

That's the bit where your cable needs to go over.

I tried it today and it was awesome! It's not perfect because the cable is a bit bent but it's so much better than it used to be. It's the first time since very long that I'm shifting between the front rings without having to look down and curse my lungs out! Thanks a lot Patrick, that specific trick with the cable routing did it.

patrickf

Glad it worked for you! Shame the instructions aren't clearer.