Portis

I spent the entire afternoon outside getting sunburn, bloody fingers and mad. I replaced the drivetrain on my Trek 4300 and ran into issues. Everything went ok, until i discovered that i would have to move and readjust my front derailleur.

I replaced my old 42/34/24 crankeset with a Deore 44/32/22. The outter ring was obviously taller and i needed to raise the front der. That went ok, but I simply cant get the thing readjusted. No matter what i do, I cant get ENOUGH tension of the wire to make the derailleur go out and hit the high limit screw. My limit screw settings appear to be fine.

I just can't get enough tension on the cable to hit the high screw stop. I tried for hours. So the the chain rubs badly in on the outer part of the cage, while on the large ring.

I am wondering if my true issue is that i may have a crankset that was not designed for my derailleur? I did a bit of research and learned that my C050 Shimano derailleur is supposed to take a MAX large ring with 42 teeth. Mine has 44.

Also the max difference is supposed to be 18 T between large and small, mine is 22. Is this enough to cause the trouble i am speaking of? I have never had this much trouble adjusting a front derailler before. Any help would brighten my gloomy day.

sydney

Did you use the correct spildle length for the crankset and seattube diameter? Did you disconnect the cable, back out the hi limit screw and check by hand that the derailer did indeed have insufficient throw? Did you start the derailer adjustment with chain on big cog and small ring with loose cable and about .5mm clearance between chain and inner plate, with shifter in small ring position? The derailer may be a bit out of spec for the crank,but that is unlikely the base issue.

Portis

Spindle length is 113. That is what it called for. I can push the derailleur by hand or pull the wire and it will go out and hit the outer limit. I just can't shift to it by pulling on the wire. It takes a helluva force to do it. I don't know how i could ever get the wire that tight.

I also can move it out to the limit and clear it with the cable disconnected, yes.

I set L limit by having chain on small chain ring and large cog. It is barely not rubbing.

I set H limit by having chain in outer/outer with barely no rub. I just can't activate the shifter and actually get it to go out and hit the outer limit. I can pull it by hand and it is happy.

Portis

I think you are right. The base issue is that i can't get enough tension on that cable. I don't know why. I am sure i am doing something wrong.

nitropowered

Front derailluers don't cost that much. Since you are running out of spec, try getting a new one.

Portis

That is my next plan. I just want to get it rideable in the meantime. Tomorrow is Sunday.

sydney

You got the cable attached to the arm correctly? I think you got enough tension,but the throw is wrong. Too much initial tension will pull the derailer off the low limit and hose shifting to the small ring.

Portis

I don't know at this point if it is right or not. I need to sleep and look at it again tomorrow. It has been a long day. I also plan to replace the cable, it got frayed in the process today.

operator

Yeah a new der is like $10 for a cheap shimano one.

hypersnazz

If anything your running out of spec would cause the chain to rub the bottom guide while in the small chainring, not the outside while in the large like you're describing. The actual space between the rings *should* be the same. I mean, you could always get out a set of calipers and measure the distances between the rings on your old and new cranksets and at least eliminate that question. Obviously if the ring spacing is different, a new derailleur will be necessary. But it sounds more like something isn't routed correctly or the cable is hung up somewhere (like maybe it's not in the right channel on a D-pull derailleur or something).

sydney

I don't seem to find any specs relating to that nonsense.

Portis

It is a 9 speed crankset on an 8 speed setup. I was told that this was ok. Wouldn't the spacing between the chainring centers be the same regardless of whether it was an 8 or 9 speed crankset? IOW, the shifter should have to move the derailleur the same amount regardless if it is 8 or 9?

I will play some more with it today. I was able to get enough tension on the cable to complete the shift to the outer ring this morning. However, that made it so it wouldn't shift back to the small ring from the middle.

I had to screw the thumbscrew all of the way out to achieve this. Then, like i said it wouldn't work on the inner ring. If i get it set up to where it will shift on the two inner rings ok, than it won't go to the outer. Right now it shifts reasonably well between the two inner rings. But when i try and shift to the large 44 tooth ring using the shifter, it seems like the chain jams into the inside of the large ring and never "rides up" to land on it, like it should. It just smashes into it.

I can make it go ahead and "ride up" to the outer chainring if i pull the wire by hand. Otherwise the shifter just pushes it into the side of the large ring and never completes the shift on to it.

sydney

The difference between an 8 and 9 speed crankset is marketing.That is not the issue. As stated before, when you dial in too much tension,you hose the shift to the smal ring,because the extra tension won't allow the derailer to drop to the low limit. I'm assuming you have used the FD before and that the cable routing and attaachment is correct?? I can't tell from the picture,but it looks suspect. You might also try raising the FD a bit more.

Portis

I have an identical bike to look at for reference. I attached the cable in the same manner as the other properly functioning bike. So i'm assuming it is ok. The derailleur, cable, housing etc. was all working fine with the other crankset. I ride the bike nearly every day.

I just need to play with it some more. I know that the fact that the derailleur isn't spec'd for my crankset is a problem, i just don't know to what degree yet.

sydney

As others have said, A FD is relatively cheap. When I have somethng that doesn't work and I know my adjustments are not at fault,then I dig in the parts box for somethng else. I've had FDs that should have worked,but just didn't.

Portis

Trouble is...my parts box is comprised of, well...........not much. Guess I will make a trip to Nose Picker Central (LBS) and see what they have to offer. Or i might just order one online, sort of depends on what flavor of frustration I am in the mood for.

Portis

UPDATE

Well a couple hours later and i am relatively happy with my front derailleur setup. I don't know exactly what i was doing wrong, but it seems like i got the most good from lowering the front derailleur even more. It now has a penny's thickness of clearance as park tool suggest. It was probably 3 pennies before.

I don't have a clue why that helped but it did. I think it is because my derailleur doesn't like that large chainwheel, but i am just guessing. I don't know exactly where i will head from here. I think i will take it for a ride tomorrow and see how it rides. I know my shifting is far from perfect but i will work with it.

cascade168

Just as a point of reference ... Three pennies stacked will give you ~4.5mm. Any of the FD alignment proceedures (that I have seen) from Shimano state that the range of adjustment for this gap should be in the 1-3mm range. Having made all of those mistakes myself on more than a few occasions, I can tell you that you will have a much easier time if you are closer to the 1mm end of the spec than at the 3mm. At 4.5mm you really don't have much of a chance of it working properly. This is even more true, in your case, as you are pushing the spec limits of the FD by using the larger chainring. I think the easiest mistake to make in aligning an FD is to not pay extremely close attention to the height and angle (rotational around the seat tube) adjustments. If you don't get these correct, your limit and tension adjustments will be very difficult, if not impossible, to get working properly. Yes, a penny (at 1.5mm) is a good clearance measure.

Al1943

Generally speaking the lower the derailleur is the better, as long as the chain has clearance.
Something that I would check again is the part about having the shifter in the small ring position before attaching the cable. What I would do is shift to the small ring and large cog. Detach the cable, flip the small shifter a few time while pulling the cable from the free end. This is to make sure you have all of the cable out of the shifter and all of the slack out of the cable. Then re-attach the cable to the derailleur. You can then add a little tension to the cable, but you shouldn't need that much. Try it.

Al

harlantk

Just a thought here on this, of what about the cable housing, maybe worn and with the rise in action, some loss in the lower housing taking away from the full stretch of the cable. ???
Just a thought

DannoXYZ 

I'm with Cascade on this one. Go to the ParkTool website and look up their FD procedure. Very, very first step before messing with any cable tensions and limit-screw adjustments is to make sure the vertical height of the derailleur is within spec. Shimano specifies something like 1-2mm for the outer-cage away from the teeth, I always aim for 1mm because it gives noticably better shifting than 2mm. At 5-6mm like you've got in that picture, you're sacrificing A LOT of functionality. Sure, it'll still work, but not as well as it can.

The 2nd critical factor is the outer-cage rotation. The ParkTool guys got it right also. Put your chain into highest-gear big-ring/small-cog combination and rotate teh FD so that the cage is parallel to the chain. The rear of the cage should stick out a little bit. This is so hard for people to get right that Shimano even came up with a neat outer-cage shape with a step in the tail-end of the cage that jumps out about 3mm so that when people use the standard shop-practice of putting the cage parallel to the chainring, the rear ends up poking out just the right amount.

Finally, the tip of the inner cage is what really drives the chain up from the small-ring to the big-ring. You want to bend the tip of the inner cage so it points towards the outside a little. This causes it to grab the chain quicker and shove it up. Again, Shimano incorporated this into their newer FDs with a built-in bent tip. From the looks of the photos, you can improve shifting significantly by bending the tip of that inner cage in by about 2-3mm. Do it gradually so that this occurs over 10mm or so.

Once the physical alignment is optimized, THEN can play with cable-tensions and limit screws.

hypersnazz

Dude, get over yourself and learn to read. "If" makes this a conditional statement, I suggested he actually measure the spacing (which you haven't done either) and take appropriate steps, which apparently were not necessary. Sheesh.

sydney

^^^ ...and what would the appropriate specs be if there aren't any derailer specs for it??