Help Front derailleur won't shift under load - stories of the Noob

Dec 17, 2011
267
8
38
kanazawa
#1
Hello guys,

Another week, another noob story. After my bad experience with the hand pump, now there's another thing I want to ask. The front derailleur of my Defy 3 will not shift if I'm pedaling; the heavier I pedal the harder it is to swift. Why the hell does this happen? The derailleur is a Shimano 2300.

In the first week, the thing would just swift flawlessly, without any problems. But, come second week, I was unable to even make it shift at all. So, I headed to Y's akasaka for a setup. After several hours, numerous different setups and generally breaking the balls of the stuff there, I could somehow/sometimes shift (the stuff there must now hate me :eek:). But, after a few failed attempts, I noticed it was easier to shift under lighter load; now I practically stop pedaling for a moment and then shift, it works 99% of the time.

But this is wrong! Any insight on why this happens?
Cheers!
 
Jan 14, 2007
2,515
213
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Noda
japanichiban.com
#2
Hello guys,

Another week, another noob story. After my bad experience with the hand pump, now there's another thing I want to ask. The front derailleur of my Defy 3 will not shift if I'm pedaling; the heavier I pedal the harder it is to swift. Why the hell does this happen? The derailleur is a Shimano 2300.

In the first week, the thing would just swift flawlessly, without any problems. But, come second week, I was unable to even make it shift at all. So, I headed to Y's akasaka for a setup. After several hours, numerous different setups and generally breaking the balls of the stuff there, I could somehow/sometimes shift (the stuff there must now hate me :eek:). But, after a few failed attempts, I noticed it was easier to shift under lighter load; now I practically stop pedaling for a moment and then shift, it works 99% of the time.

But this is wrong! Any insight on why this happens?
Cheers!
Are you lining up the back wheel cogs in an easy combo when shifting?
ie. Not bigger on the back to biggest on the front and vice versa?

You want your chain to be fairly straight when shifting...
 

kiwisimon

Maximum Pace
Dec 14, 2006
2,670
483
103
Japan
#4
What shifters are you using? Pedalling or not shouldn't make the action lighter, are you going from small chainring to big or big to small?
 
Jan 14, 2007
2,515
213
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Noda
japanichiban.com
#5
Thanks for the reply!

Yes, I do keep reasonable combos and don't use the extremes. However, the problem persists, regardless of the gear combo...
My second guess then maybe that by trying to switch under force you may be stretching the cable...

You should always shift as effortlessly as possible and not while grinding with your down pedal stroke... smooth and easy always.... switch into the easier gears before you need them not after...
 

StuInTokyo

Maximum Pace
Dec 3, 2010
1,662
62
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#6
You have two or three chainwheels up front?

Shifting from the smaller chainwheel to the larger, or from the larger to the smaller?

Cables stretch with use, but only a week? Check the front derailer cable where it runs along the frame of the bike, maybe it got hit by something and crimped the cable housing...?

Undo the cable from the derailer, then see how smoothly the shifter shifts, if it is still hard to shift, as in the shifter moving without binding.

OK a bit of googling and it looks like you have the Sora brifters on that bike (brakes and shifter combo = brifters) I have the same set up on my Lrrb, and the front shifter is far from being very nice or smooth, in fact is sucks! :rolleyes:

So check if you can see any damage to the cable housing for the front brifter, then disconnect the cable from the derailer and see if the brifter moves easily or not. While the cable is disconnected, with your hand just move the derailer back and forth, does it bind? Does it move easily?

This is a very simple part of the bicycle and should not be hard to figure out why it is not working.

Good luck, keep posting questions if you have them!
 
Dec 17, 2011
267
8
38
kanazawa
#7
My second guess then maybe that by trying to switch under force you may be stretching the cable...
You have two or three chainwheels up front?

Shifting from the smaller chainwheel to the larger, or from the larger to the smaller?

Cables stretch with use, but only a week? Check the front derailer cable where it runs along the frame of the bike, maybe it got hit by something and crimped the cable housing...?

Undo the cable from the derailer, then see how smoothly the shifter shifts, if it is still hard to shift, as in the shifter moving without binding.

OK a bit of googling and it looks like you have the Sora brifters on that bike (brakes and shifter combo = brifters) I have the same set up on my Lrrb, and the front shifter is far from being very nice or smooth, in fact is sucks! :rolleyes:

So check if you can see any damage to the cable housing for the front brifter, then disconnect the cable from the derailer and see if the brifter moves easily or not. While the cable is disconnected, with your hand just move the derailer back and forth, does it bind? Does it move easily?
Thanks for the advice guys!

Including the assessment from the guy at Y's, there's a total of three opinions quoting cable stretch! At Y's I explained them that the loss of shifting was happening gradually over the week. I was told that:
a) that the original settings were kind of "bad" and
b) that "it's only a theory but I think that the cables stretched over the past week".

Further info: there are 2 chainwheels on the front and the problem appears when shifting from the inner chainwheel to the outer one.

I can shift when I'm under very little load (or not pedaling at all) but that doesn't seem logical! When I try to shift under load, I get tons of crackling sounds of the chain hitting against (i think) the bigger chainwheel. During this kind of failed shifts, the chain is in ... "limbo", between the two chainwheels.

How's is it possible that under stress the derailer cannot perform the shift? what parts can possibly be negatively impacted under load?

p.s. Thanks also for the maintenance tips! Currently I'm lacking even basic tools (i.e. screwdriver), but I should be able to have a look on Saturday and report back any findings! Cheers!
 
Jan 14, 2007
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213
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japanichiban.com
#9
Thanks for the advice guys!
How's is it possible that under stress the derailer cannot perform the shift? what parts can possibly be negatively impacted under load?
The teeth! I've broken them trying to switch into an easier gear on a very steep climb... you need to switch before there is pressure...
The teeth want to pull you forward....but if the chain is dragging sideways at force you'll snap the teeth.
The chain is looking for the teeth and if your putting too much pressure on it..it doesn't have time to bite the hole. You may be forcing it to go where it doesn't want to go...
 

StuInTokyo

Maximum Pace
Dec 3, 2010
1,662
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#10
There are also limit screws on the front derailer, this will stop the shift from going too far, as in dumping the chain inside of the smaller chainwheel, or dropping it over the larger chainwheel. If the outer limit screw was set incorrectly it may not be allowing the derailer to carry the chain far enough to engage the outer, larger chainwheel.

Here is a good video on the subject...

http://www.youtube.com/watch?v=1tQxJqGVznM
 

GSAstuto

Maximum Pace
Oct 11, 2009
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tokyo
www.roadfixie.com
#11
My guess is that the cable housing where it goes into the shifter is damaged. If the bike was assembled without using a ferrule at the end of the cable then over time it will mush out causing this exact symptom. Aside from that - adjusting the front derailer is a no brainer. Shift into your smaller gear in the front, then make sure the cable is snug. It should be snug enough that when you just start to use the shift lever, you see movement of the front derailer.

Then, shift into the larger ring. If it doesn't go all the way in - like you hear 'clack clack' , then chances are the limit screw needs to be turned out a little so the derailer can move a little more. If you turn too much and the derailer goes too far when you shift - then you'll drop a chain on the outside (not fun).

But , unless the cable is snugged up in the smaller gear, you won't have enough shift travel to make it into the top gear. This is just part of the funkiness of Shimano - especially the lower end (below 105) shifters. Everything has to be snug and adjusted right for it to work perfect.

And , you can't forget those ferrules or housing end caps! They support the cable housing at the end where it fits into the shift levers.
 

AlanW

Maximum Pace
Jan 30, 2007
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Tokyo
#12
Front derailleurs generally will not shift under a heavy / full load. They are very low-tech, simply bashing the side of the chain until it catches on the other ring teeth. Even the high-end stuff like Dura Ace, Record and Red struggles with the shift under full load. It's better to ease off the pedals as you make the shift, just easing off the power, not stopping pedalling.

However, as you said when you got the bike it would make the shift originally, and you also said it was new, I would agree with the other posters....you have a cable stretch problem. New cables tend to stretch and bed-in. You need more tension in the cable, adjusted by the rotary (barrel) adjuster for fine adjustments or by undoing the cable clamp at the derailleur and pulling more cable through for gross adjustments.
You may also have damage as suggested by Tim (GSAstuto) and it's also possible that the cage of the derailleur is bent, or that the derailleur has slipped on the frame and is out of position.
 
Sep 2, 2009
5
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0
#13
To the OP: is there any chance of making a video of the problem and posting it up? Just use your phone.

That would make things a lot easier to diagnose.

Cheers.
 
Dec 17, 2011
267
8
38
kanazawa
#14
Thanks guys for your replies!

Tomorrow I'll be getting a bike stand, so I can try to work on the bike. I'll check everything that's been posted so far and I'll post any progress made!
Cheers!
 
Oct 15, 2010
669
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#17
I put it through the paces today patching a tyre on my wife's fixed gear moma chari. Wow. That was a challenge. Wheel was bolted on, there was a kickstand, child seat, fender, and part of that was attached to the seat - the coaster break was attached to the frame, there was a chain guard too. Felt like I was putting a puzzle back together or playing with Lego: there were so many pieces.

I ended up moving the bike stand outside so I could keep an eye on my kids. When getting the stand I was worried I should maybe go for one of the more portable ones, but this one is not too heavy, and the feet swivel down when it is picked up making it easier to get through doors etc.

The stand is stable, and I am happy with it. Considering the price and what I want it for, it is perfect. I did see one review saying it was not the most durable one around, and I imagine if one were to keep swiveling the clamp around various angles without care, the teeth that hold it in place could get mashed up over time, but I will be careful and do not intend to have my bike in various positions.

Pictures are attached. Let me know if you have any questions.
 

StuInTokyo

Maximum Pace
Dec 3, 2010
1,662
62
78
#18
I put it through the paces today patching a tyre on my wife's fixed gear moma chari. Wow. That was a challenge. Wheel was bolted on, there was a kickstand, child seat, fender, and part of that was attached to the seat - the coaster break was attached to the frame, there was a chain guard too. Felt like I was putting a puzzle back together or playing with Lego: there were so many pieces.

I ended up moving the bike stand outside so I could keep an eye on my kids. When getting the stand I was worried I should maybe go for one of the more portable ones, but this one is not too heavy, and the feet swivel down when it is picked up making it easier to get through doors etc.

The stand is stable, and I am happy with it. Considering the price and what I want it for, it is perfect. I did see one review saying it was not the most durable one around, and I imagine if one were to keep swiveling the clamp around various angles without care, the teeth that hold it in place could get mashed up over time, but I will be careful and do not intend to have my bike in various positions.

Pictures are attached. Let me know if you have any questions.
Thanks for the pics, it does look good.

How easily does the clamp open and shut?
Do you think the yellow knob is sufficient for clamping pressure to hold the bike? Remember not all bikes are as light weight as your bike :D I guess if it could hold up your wife's Mama-Chari it must be able to clamp fairly tight :cool:

It looks like you flip the lever on the back with allows the head of the clamp to rotate, when you get it in position, you release the lever which then sets between two teeth stopping rotation, correct?

BTW the easy way to fix a flat on the rear wheel of the Mama-chari, you just unseat one side of the tire and take the tube out, and work on it......

http://www.youtube.com/watch?feature=player_detailpage&v=bBt-C3DBkqA

Easy as can be :D

PS sorry for the hijack not this thread :eek:
 

Desune

Speeding Up
May 7, 2008
64
0
26
Tokyo
#19
I can shift when I'm under very little load (or not pedaling at all) but that doesn't seem logical! When I try to shift under load, I get tons of crackling sounds of the chain hitting against (i think) the bigger chainwheel. During this kind of failed shifts, the chain is in ... "limbo", between the two chainwheels.

How's is it possible that under stress the derailer cannot perform the shift? what parts can possibly be negatively impacted under load?
!
Normally the front derailleur will move further than is really ideal, to get the chain to ride up on the large chain wheel more effectively. This is one of the reasons why there is a trim function on the front brifter to budge the derailleur back after the shift. I'm not sure if Sora has this, but my Dura Ace does.

If you do in fact have a stretched (or slipping) cable, then the brifter won't be pulling quite enough. The tolerance can be pretty slight. Under light load, there is less stress on the chain, allowing an easier shift. Under heavy load, it may just not be moving over far enough to get the chain over easily because of the skewed pull direction towards the rear. It should be slightly easier to shift the further you get towards the smaller sprockets.

In any case, I would re-attach and the cable and re-adjust the front derailleur.
 
Sep 2, 2009
5
0
0
#20
Normally the front derailleur will move further than is really ideal, to get the chain to ride up on the large chain wheel more effectively. This is one of the reasons why there is a trim function on the front brifter to budge the derailleur back after the shift. I'm not sure if Sora has this, but my Dura Ace does.
Erm, no it isn't. The trim is there to cope with a wide range of chain lines, without the front mech rubbing.