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front derailleur

Old 09-22-21, 09:01 AM
  #26  
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Originally Posted by cyccommute

Try cable adjustment before you replace the derailer. If the cable adjustment doesn’t work, try tuning the limit screws.
Maybe he should figure out what the problem actually is before randomly adjusting cable length or 'tuning' the limit screws.
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Old 09-22-21, 09:08 AM
  #27  
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Originally Posted by Awesomeguy
I know that front derailleur problems are common, but is it beneficial in this regard if you have higher end components, like deore or shimano 105 etc.??


I have Acera front derailleur and Alivio rear derailleur, rest of the bike is acera.
I know 1X is a trend right now, but i think i like 2X most since you wide range of cadence\gear options.
Without more information about your problem and maybe even without seeing your bike in person, I wouldn't begin to imagine you need "higher end components".

This is a bike that came with that stuff already installed isn't it? Unless this is some POS brand, which Trek is not, then the mfr. likely put stuff on it that works well enough. So I'd go with the idea that something is either out of adjustment or out of alignment. And as tossed about, the limit screws typically are not the fix for a bike that previously had no issue.

Or has the bike always done this? If so, then I will be of the opinion that you should have taken it back to the shop you bought it from so they could fix it.
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Old 09-22-21, 09:21 AM
  #28  
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I totally try it out right now, my only issue, is i don't have one of those stands to troubleshoot, i might have to order it, since, taking it to the shop each time , can be a bit much .
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Old 09-22-21, 09:23 AM
  #29  
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Originally Posted by restlessswind
Fun Fact: 78.327% of statistics are made up.
In this case, you're 100% correct.
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Old 09-22-21, 10:20 AM
  #30  
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Originally Posted by Maelochs
Acera and Alivio are not great groups .... but they are serviceable. They will do the job. In my experience the lower-end Shimano stuff flexes more, and seems to stay adjusted less, than the good stuff. But ... it all works.

I have an Acera RD on my Cannondale tourer, and a Claris triple FD ..... and I have zero complaints. (Claris is comparable to Acero, just road vs MTB-oriented.) Set them up right, ride them, and if they need a tweak now and then, an 1/8 turn on the barrel adjuster usually does it.

The important thing with derailleurs is having a clue how to set them up. I don't, so I visited Park Tools' website and both printed the text and copied the video links for their instructions. That, plus a couple other YouTube videos, made setting up, adjusting, and indexing seem as simple as it actually is.

I sometimes have a hard time following seemingly complex instructions because I try to remember everything. Some stuff just seems daunting. I just learn step-buy-step, make sure I understand each step, and then after I am sure I know Step One, I move on. Eventually the stuff I thought was super-complicated and difficult, is commonplace and simple.

My advice would be, Don't just go in there turning screws and barrel adjusters randomly, to see what happens. Cable tension and limit screws affect each other---if the cable isn't pulling the derailleur all the way to the limit, then you can turn the screw until it falls out .... and if the derailleur hits the inner (L) screw turning the barrel adjuster won't do a thing---but then, when you finally get the limit screw properly adjusted, the cable will be an issue because you adjusted it for a different range of motion.

And with the rear derailleur, if you have removed the "dork disc" on your rear hub, and if you set the rear Low limit screw too far out, your derailleur will dive into your spokes, often ripping the derailleur off the frame, bending the derailleur hanger, and maybe breaking a couple spokes. Guaranteed highlight of your day.

Go slowly through the instructions. They are Not complicated, taken in small pieces. Think about how complex the instructions for tying and double-knotting shoelaces would be, printed out ..... adjusting your derailleurs and cables is a lot simpler than that.
what is considered a group set?
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Old 09-22-21, 10:53 AM
  #31  
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Originally Posted by cxwrench
Maybe he should figure out what the problem actually is before randomly adjusting cable length or 'tuning' the limit screws.
Awesomeguy has to start somewhere. Considering that the problem is likely cable length, that’s the place to start. It’s simple and easy to fix if that isn’t the problem. I agree that tuning the limit screws probably isn’t necessary which is why I suggested doing that only after trying to adjust the cable.
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Old 09-22-21, 11:18 AM
  #32  
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Originally Posted by Awesomeguy
I totally try it out right now, my only issue, is i don't have one of those stands to troubleshoot, i might have to order it, since, taking it to the shop each time , can be a bit much .
You don’t need a stand. The likely problem…cable tension…is something that you can check with the bike sitting on the ground. Assuming that you have Acera shifters, shift into the large chainwheel and let go of the shifter. Then, without pedaling, push on the same lever you used to shift into the large chainring. If the cable is properly adjusted, the derailer should be up against the stop and won’t move. Dollars to donuts, I would bet that your front derailer will move outboard just a little bit when you push on that shift lever.

An alternative would be to shift to the inner ring so that all tension is relaxed on the front shift cable. Pull on the cable (gently) to see if there is any slack in the cable. Front derailer cables need to be a little tighter than rear ones. If there is slack, use the barrel adjuster to take up the slack.

If the derailer moves, tighten the cable with the barrel adjuster by turning it away from you as you sit on the bike. You probably won’t need more than a quarter of a turn.

If you don’t what to hold the bike up while you do this, get a toe strap or belt or some other strap. Find a pole and wrap the strap around the pole and the stem. You can do a lot to a bike with strapped to a pole. I often do work to my tandem this way because getting it up on the rack is a bit of a chore. Since this is a static job…you don’t need to spin the crank nor spin the wheels…strapping it to a post works really well.

I even have a nail hammered into a post for my porch for this purpose.


Lean the bike against the post



Strapped down. The bike won’t fall over and you’ll have your hands free to make adjustments.

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Old 09-22-21, 12:50 PM
  #33  
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Originally Posted by Awesomeguy
what is considered a group set?
Something like this: https://www.merlincycles.com/road-bike-groupsets-75294/
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Old 09-22-21, 12:55 PM
  #34  
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Cyccommute is mostly right. If i were in your situation, I would adjust the front cable tension as I suggested above---I wuold actuyally start from scratch, but you probably---Probably---just need to turn the front barrel adjuster and eighth or a quarter turn.

As he suggests, shift into high and yank the cable and see if the derailleur swings further outward. if it does the cable is loose and the limit screw is probably fine--and if the screw also needs adjustment, you can't do it properly without adjusting the cable tension anyway.

I am completely serious here---having been in many situations just like this. Stand the bike up somewhere, shift the front derailleur into high, and yank the cable---see if the derailleur moves. This is the first test I would perform if it were my bike--or if it were yours and you were a friend.
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Old 09-23-21, 07:26 AM
  #35  
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Originally Posted by cyccommute
... I’ve even picked up the name “derailer whisper” at my co-op.


As the resident 'whisperer' you may want to research how to spell 'derailleur' correctly. That might help with your street cred.
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Old 09-23-21, 07:35 AM
  #36  
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​​​​​​https://www.sheldonbrown.com/deraile...%20that%20when
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Old 09-23-21, 09:44 AM
  #37  
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Originally Posted by redcon1
As the resident 'whisperer' you may want to research how to spell 'derailleur' correctly. That might help with your street cred.
What he ^^^ said ^^^
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Old 09-23-21, 11:12 AM
  #38  
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Originally Posted by cyccommute
I’ve even picked up the name “derailer whisper” at my co-op.
When someone calls you a "whisperer" it's a compliment. When someone calls you a "whisper" it's not.
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Old 09-23-21, 11:25 AM
  #39  
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Originally Posted by redcon1
As the resident 'whisperer' you may want to research how to spell 'derailleur' correctly. That might help with your street cred.
Originally Posted by tomato coupe
When someone calls you a "whisperer" it's a compliment. When someone calls you a "whisper" it's not.
So what have either of you contributed to the conversation? Any suggestions or are you just here to play unfunny versions of Statler and Waldorf? At this point, I’d say ya got nothin’.
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Old 09-23-21, 11:30 AM
  #40  
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Originally Posted by cyccommute
So what have either of you contributed to the conversation? Any suggestions or are you just here to play unfunny versions of Statler and Waldorf? At this point, I’d say ya got nothin’.
The Statler and the Waldorf are both hotels, aren't they? I've never seen a funny hotel.
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Old 09-23-21, 11:38 AM
  #41  
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Originally Posted by tomato coupe
The Statler and the Waldorf are both hotels, aren't they? I've never seen a funny hotel.
Whoosh! Not “the”.
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Old 09-25-21, 03:49 PM
  #42  
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I ended up taking it to bike shop , he also lubed the chain and it made a world of difference .. rides like new
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Old 10-19-21, 10:27 AM
  #43  
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Originally Posted by Maelochs
Cyccommute is mostly right. If i were in your situation, I would adjust the front cable tension as I suggested above---I wuold actuyally start from scratch, but you probably---Probably---just need to turn the front barrel adjuster and eighth or a quarter turn.

As he suggests, shift into high and yank the cable and see if the derailleur swings further outward. if it does the cable is loose and the limit screw is probably fine--and if the screw also needs adjustment, you can't do it properly without adjusting the cable tension anyway.

I am completely serious here---having been in many situations just like this. Stand the bike up somewhere, shift the front derailleur into high, and yank the cable---see if the derailleur moves. This is the first test I would perform if it were my bike--or if it were yours and you were a friend.
im getting the run again lol, so how is cable tension related to high and low limit screws?
If I bring the derailleur outward do I have to slacken the cable first ?
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Old 10-19-21, 11:09 AM
  #44  
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Originally Posted by Awesomeguy
im getting the run again lol, so how is cable tension related to high and low limit screws?
If I bring the derailleur outward do I have to slacken the cable first ?
Cable tension really isn’t related to the limit screws. The limit screws only set the travel distance. The low limit screw prevents the derailer from moving too far inboard while knocking the chain off the inner chainwheel. The high limit screw limits how far outboard the derailer can move and prevents the chain from falling off the outside.

The cable, on the other hand, is what moves the derailer between those two limits. If the cable is too slack, the derailer can’t move far enough outboard so that the chain jumps up to the largest cog. If it is too tight, it won’t allow the chain to move to the inner chainwheel. The former…i.e. cable too tight… is by far the most common problem.

Understanding the relationship between the cable tension and how the derailer (front or rear) moves is the key to understanding derailers and keeping them working properly. Far too often people think the limit screws are the key. They are not.
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Old 10-19-21, 11:46 AM
  #45  
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Awesomeguy The word "tension" in cable tension might cause you to imagine mysterious things that have no impact on setting your DR's up correctly. Think of it as cable "length". What you are doing when you attach the cable to the pinch bolt or turn a barrel or inline adjuster is setting the length of the cable. Not it's tension. If you are in fact changing the cable tension when you adjust the barrel or inline adjusters, then you might be against the stop and not doing anything or something else is wrong.
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Old 10-19-21, 03:38 PM
  #46  
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Originally Posted by cyccommute
Cable tension really isn’t related to the limit screws. The limit screws only set the travel distance. The low limit screw prevents the derailer from moving too far inboard while knocking the chain off the inner chainwheel. The high limit screw limits how far outboard the derailer can move and prevents the chain from falling off the outside.

The cable, on the other hand, is what moves the derailer between those two limits. If the cable is too slack, the derailer can’t move far enough outboard so that the chain jumps up to the largest cog. If it is too tight, it won’t allow the chain to move to the inner chainwheel. The former…i.e. cable too tight… is by far the most common problem.

Understanding the relationship between the cable tension and how the derailer (front or rear) moves is the key to understanding derailers and keeping them working properly. Far too often people think the limit screws are the key. They are not.
so my issue is that the shifts are perfectly fine, it’s just in the bigger ring (2x) up front , and biggest three gears in the back , chain rubs the outer plate. If I just loosen the h screw , to bring derailleur outward , with that work? Also if I listen or tighten the high or low screws does that man I need to adjust barrel adjuster ?
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Old 10-19-21, 05:58 PM
  #47  
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Originally Posted by Awesomeguy
so my issue is that the shifts are perfectly fine, it’s just in the bigger ring (2x) up front , and biggest three gears in the back , chain rubs the outer plate. If I just loosen the h screw , to bring derailleur outward , with that work? Also if I listen or tighten the high or low screws does that man I need to adjust barrel adjuster ?
Again, the limit screws only limit how far the derailer moves but not how it moves. Chain rubbing in extreme gears…like the biggest cog on the rear with the large chainring…is somewhat normal. It can be a function of the derailer or the derailer alignment but even then, you are more likely to experience chain rub in those combinations. If you are using Shimano front derailers, the more expensive ones tend to rub more in my experience. Those tend to be narrower than cheaper versions (Tiagra and lower).

Your shifters should also have a “trim” feature which is a soft click (like about a half shift) in the shifter. This will move the front derailer just a little bit in those more extreme gears and reduce rub. I use triples exclusively and the trim is in the middle ring. I don’t recall if it is on the inner ring or outer ring on doubles.

Finally, you don’t need to use the large ring/large(r) cog combinations. Use a gear calculator and see where those gears are duplicated. Shift before you get to the gears that tend to rub.
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Old 10-19-21, 06:20 PM
  #48  
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Originally Posted by cyccommute
Again, the limit screws only limit how far the derailer moves but not how it moves. Chain rubbing in extreme gears…like the biggest cog on the rear with the large chainring…is somewhat normal. It can be a function of the derailer or the derailer alignment but even then, you are more likely to experience chain rub in those combinations. If you are using Shimano front derailers, the more expensive ones tend to rub more in my experience. Those tend to be narrower than cheaper versions (Tiagra and lower).

Your shifters should also have a “trim” feature which is a soft click (like about a half shift) in the shifter. This will move the front derailer just a little bit in those more extreme gears and reduce rub. I use triples exclusively and the trim is in the middle ring. I don’t recall if it is on the inner ring or outer ring on doubles.

Finally, you don’t need to use the large ring/large(r) cog combinations. Use a gear calculator and see where those gears are duplicated. Shift before you get to the gears that tend to rub.
when I say big gear in the back, I man the smallest cog in the back and largest upfront
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Old 10-19-21, 08:53 PM
  #49  
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Originally Posted by Awesomeguy
when I say big gear in the back, I man the smallest cog in the back and largest upfront
Okay. Got ya now. Most people talk about the “big gear” in back as the largest cog. You’ve got it the right way around because the smallest cogs are the highest gears. Now that I have it straight and we’re on the same page, we can proceed with looking at solutions. There’s a couple of things to check. First look at the derailer alignment. The picture below shows what your problem could be. “C” is the proper alignment. The outer plate should be parallel with the chainwheels. Either A or B could result in chain rub over multiple gears in the back.



Your issue could still be a cable issue or may also be a cable issue. Both could happen simultaneously. Shift down to the lowest gear in the front and see if your cable is tight. If it is loose, the derailer won’t move out far enough. The cable should be fairly tight.

Another, more complicated, possibility could be the chain line isn’t right. After you’ve checked everything else first, see if you can move the front derailer outboard by hand. You might have to loosen the height limit screw to see if you can move it out any more…again by hand. If you can’t move it out any further and it is still rubbing, you might need to move the drive side inboard. It’s fairly easy with the crank you have. You will just need to move spacers from the drive side to the nondrive side. It’s a little complicated but not too difficult to do. The crank is easy to remove and you just need a tool to remove the bottom bracket cups. Move the driveside spacer to the nondriveside.

You might not need to move all 2.5mm from the drive side depending on how much you need to move the chainline. You can get spacers in different thicknesses to tune the amount you need to move the crank if you don’t need the full 2.5mm.

Try the other fixes…they are easier…first.
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Last edited by cyccommute; 10-20-21 at 09:12 AM.
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Old 10-20-21, 07:09 AM
  #50  
Awesomeguy
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Originally Posted by cyccommute
Okay. Got ya now. Most people talk about the “big gear” in back as the largest cog. You’ve got it the right way around because the smallest cogs are the highest gears. Now that I have it straight and we’re on the same page, we can proceed with looking at solutions. There’s a couple of things to check. First look at the derailer alignment. The picture below shows what your problem could be. “C” is the proper alignment. The outer plate should be parallel with the chainwheels. Either A or B could result in chain rub over multiple gears in the back.



Your issue could still be a cable issue or may also be a cable issue. Both could happen simultaneously. Shift down to the lowest gear in the front and see if your cable is tight. If it is loose, the derailer won’t move out far enough. The cable should be fairly tight.

Another, more complicated, possibility could be the chain line isn’t right. After you’ve checked everything else first, see if you can move the front derailer outboard by hand. You might have to loosen the height limit screw to see if you can move it out any more…again by hand. If you can’t move it out any further and it is still rubbing, you might need to move the drive side inboard. It’s fairly easy with the crank you have. You will just need to move spacers from the drive side to the nondrive side. It’s a little complicated but not too difficult to do. The crank is easy to remove and you just need a tool to remove the bottom bracket cups. Move the driveside spacer to the nondriveside.

You might not need to move all 2.5mm from the drive side depending on how much you need to move the chainline. You can get spacers in different thicknesses to tune the amount you need to move the crank if you don’t need the full 2.5mm.

Try the other fixes…they are easier…first.
so if i undo the h screw, to move the outer plate outward, do i need to losen the cable before hand?
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