# Why is my chain dropping



## PoorCyclist (Oct 14, 2010)

I hope everyone is having a good xmas!

Me, I am not sure why my chain would drop,
first it was on a stand on the biggest cog in back and I shifting the front, Not something I do on the road so I avoid this.

And today in the big ring, chain line is straight (middle cog in the back), shift into the inner chain ring and bam it dropped. I was afraid it would lead to chain suck so I stopped pedalling even though I have a chain catcher, I noticed the chain is not on any teeth anywhere, although the catcher did keep it from falling off, still wasn't nice for the paint in front of the crank as the chain bunched up there.

The inner limit is set so the chain just touches the cage slightly in the largest cog. So it's fairly conservative.

Here is a pic, maybe it can be moved down a little bit? Also the cable touches the derailleur in the inner chain ring position.

It just seems there is so much energy in the spring compared to what I am used to.


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## looigi (Nov 24, 2010)

It's dropping inside the small ring even though you have a catcher? 

Is there a lot of drag in your free hub? With the cranks stopped and the rear wheel spinning forward, is the top run of chain still a bit taught or does it droop?


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## FBinNY (Jan 24, 2009)

IMO chain drop is an unfortunate consequence of modern index front shifters. 

The front shifter operates on the upper loop of the chain, and is therefore sensitive to the chain angle and tension. Before index, riders used a bit of touch to shift the front effectively, but modern shifters lack this touch, and it's easy to get chain drop if shifting the front while the chain 
is under tension and coming from inner cassette sprockets. 

With a tight chain coming from an inside angle under a bit of tension, it tries to take a straight line the moment it disengages from the large ring, overshooting the inner. 

Shimano recognized the importance of touch when they developed Di2. If the chain is coming from an outer sprocket, the FD shifts aggressively then comes back to trim. If the chain is coming from the inside the chain, the FD moves only enough to initiate the shift, then hesitates to catch the chain before moving the rest of the way into trim. 

Unfortunately, Sram's system and strong FD spring prevent you from duplicating the light touch needed for the shift when the chain is coming from the inside.

There are two ways to prevent this, either try to shift the front while only halfway across the cassette, or lighten the pedal load a bit during the shift to de-tension the chain, or both.


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## draganM (Nov 27, 2001)

I don't know if it will affect drop but the FD looks too high. Clearance between it and big front ring is supposed to be between 1 and 2mm (.04 to .08 inches). 
IT's also easy to put too much tension on the cable, with the chain sitting it in the small cog there should be little or no tension on the cable. Shift up and then adjust the cable barrels until it's just tight enough to push the chain up. Under these conditions the chain won't "snap down" when you downshift. 
I also pedal very slowly during the downshift with no load and my chain never drops.


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## PoorCyclist (Oct 14, 2010)

Is there a "trim" on the SRAM, it feels like there is 2 clicks on the downshift.
I have Shimano on another bike with the same frame and never dropped a chain on that one.

I think the tension is a little tight, but without enough tension the front up shifts poorly, I don't have a barrel adjuster on this one so it's a little more tricky.

It works properly most of the time, the road was pitching up and slightly rough. I have applied a 3M film on the frame now but I think I am going to need some electrical tape for my ride in Sonoma with bumpy roads.


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## sp3000 (Jul 10, 2007)

Once you have addressed what others have mentioned I would also be making sure you catcher is in the correct position, the end should be as close to vertical as possible and the clearance between it and the chain should only be a hairs thick. Good luck!


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## -dustin (Jan 11, 2009)

When in little/ little, does the chain hit the cage a lot or just ever-so-slightly?


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## PoorCyclist (Oct 14, 2010)

Just curious.., can I use Shimano 7900 or 6700 FD, I think it will work fine? 
I am not liking the cable rubbing on the derailleur spring, and I know Shimano FD will clear properly.
.


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## FBinNY (Jan 24, 2009)

Tes, you can use a Shimano FD. Many Sram sponsored riders do just that because they aren't happy with Sram FDs. But it's not a migical solution, you'll still have to stay attuned to how to shift.


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## -dustin (Jan 11, 2009)

7800 or 6600 work a little better. The latest gen 10sp stuff still works, but cable tension has to be absolutely dialed. 78/6600 are a little more forgiving. I've opted for a 7800 FD on my otherwise Red bike. Girlfriend has Force + 6600.


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## Doctor Falsetti (Sep 24, 2010)

If you look closely at our DR you can see the issue......SRAM


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## wesb321 (Oct 1, 2011)

Anyone remember friction shifters? Why'd we give these up again?

I agree with the cable tension and FD height diagnosis, fine tuning is so tedious but it's all the little things working as one that make the magik happen


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## onespeedbiker (May 28, 2007)

There are several common causes for chains to drop and not engage the small chainring. The first is on the workbench, where usually you are spinning the cranks at a high RPM. Since you were in a big/big combo your rear derailleur cage was stretched to near capacity. When you shifted to the small chain ring, suddenly the chain had a great deal of slack, and if you were still spinning the cranks at a high RPM, the chain simply bounced off the small chainring. The second is the most common cause. Some shift into the small chainring just before it's needed, others shift after it's needed, when your already putting more pressure on the crank arms. When this occurs and you shift, the sudden release of the chain from the big chainring may cause the rider to suddenly spin the crank 3 or 4 teeth, again causing the chain to bounce off before engaging. Finally if you are on a bouncy road the smoothness of you cadence can be highly affected which can also throw a chain. For all three is the same solution as mentioned before; when you down shift into the small chanring, ease off on the pressure (and reduce your cadence) until you can feel the chain engage the chainring and then ride on. Sorry about the paint chips, hopefully you can find some fingernail polish to match.


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## onespeedbiker (May 28, 2007)

wesb321 said:


> Anyone remember friction shifters? Why'd we give these up again?
> 
> I agree with the cable tension and FD height diagnosis, fine tuning is so tedious but it's all the little things working as one that make the magik happen


 Remember? Two of my main rides have friction shifters. The industry gave them up because Mr Shimano noticed that racers were missing shifts and losing races. Indexing not only, when it works, make shifts more positive, it results in more shifting and a more natural cadence. When it doesn't work it makes riders pine for the days of friction shifters


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## looigi (Nov 24, 2010)

FBinNY said:


> IMO chain drop is an unfortunate consequence of modern index front shifters.
> ...
> There are two ways to prevent this, either try to shift the front while only halfway across the cassette, or lighten the pedal load a bit during the shift to de-tension the chain, or both.


Agree: With non-friction shifter, the FD abruptly moves to the small ring propelled by the spring and slowed only by the inertia of the system and cable drag. The speed of this can throw the chain to the inside of the small ring. A large difference in diameter between the two rings exacerbates this tendency. 

Disagree: IMO and experience, a bit of tension in the top run of the chain prevents this. Any slack in the top run will increase the chances. 

Also. Unless the top run is ludicrously slack, a chain catcher should prevent it.


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## GDTRFB (Feb 12, 2011)

PoorCyclist said:


> Is there a "trim" on the SRAM, it feels like there is 2 clicks on the downshift.
> I have Shimano on another bike with the same frame and never dropped a chain on that one.


You hit the nail on the head. I had endless problems with my Force FD, which no one could solve. The same mechanics who adjust my friends Shimano bikes (no drops over 1000's of miles together) could not get the Force FD to stop dropping multiple times every ride. Look at the FD design. There is a gap at the front of the cage, which makes the cage flimsy.
I put on a 6600 FD myself, and in a few minutes had drop-free shifting for ~1500 miles.
I just had to readjust the cable recently, but I'm still pretty much drop free.
I did have one or two, but it was from not pedaling smoothly or from double-shifting.
My suggestion: Get your LBS to do a warranty exchange on the Force, and use a Shimano FD. I used a 6600 (I got it for $25 on eBay, and my LBS refunded my $ for the Force), but I've read of people using 6700 & 7800.


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## j.o.e.l (Oct 7, 2009)

I used to run shimano FD with SRAM Shifters and RD. It works ok except for slight rub when running on fastest or slowest gear. I can't get rid of the rub without causing front shift hesitation.

I then switched to a Force FD and had dropping issues. I fixed this with a combination of having the absolute minimum clearance between FD and chainring teeth ~1mm, perfectly alligned FD, and setting the low limit just right. It took me a while to get it right.

It works perfectly now and much better than when I had the Shimano FD since there is no more chain rubbing.


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## PoorCyclist (Oct 14, 2010)

Does this look better? I was able to move it down by a bit

it is about as close as it gets without the cage crashing into the teeth when shifting to the big ring


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## PoorCyclist (Oct 14, 2010)

j.o.e.l said:


> I used to run shimano FD with SRAM Shifters and RD. It works ok except for slight rub when running on fastest or slowest gear. I can't get rid of the rub without causing front shift hesitation.
> 
> I then switched to a Force FD and had dropping issues. I fixed this with a combination of having the absolute minimum clearance between FD and chainring teeth ~1mm, perfectly alligned FD, and setting the low limit just right. It took me a while to get it right.
> 
> It works perfectly now and much better than when I had the Shimano FD since there is no more chain rubbing.


I think the Shimano cage is just narrower because they expect you to use the trim feature.. the SRAM is fairly wide


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## onespeedbiker (May 28, 2007)

PoorCyclist said:


> Does this look better? I was able to move it down by a bit
> 
> it is about as close as it gets without the cage crashing into the teeth when shifting to the big ring


 I didn't think there was any problem the first time, now it looks like it's too low


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## FBinNY (Jan 24, 2009)

It doesn't matter what we think. You have the bike to ride and test. 

If it improves things, then it's better.
If it makes things worse, go back to how it was. 
If it doesn't make a difference either way, at least you know it isn't the problem, and can look for other solutions, and/or adjust how and when you shift. (which IMO is the key)


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## orange_julius (Jan 24, 2003)

FBinNY said:


> It doesn't matter what we think. You have the bike to ride and test.
> 
> If it improves things, then it's better.
> If it makes things worse, go back to how it was.
> If it doesn't make a difference either way, at least you know it isn't the problem, and *can look for other solutions, and/or adjust how and when you shift*. (which IMO is the key)


Exactly. It could also be the chain was cut too short, thus too much tension. Or, too little tension. Eliminate one probable cause at a time.


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## cxwrench (Nov 9, 2004)

orange_julius said:


> Exactly. It could also be the chain was cut too short, thus too much tension. Or, too little tension. Eliminate one probable cause at a time.


the chain being a link or 2 longer or shorter won't change the 'tension' on the top run of chain, where the derailleur does the shifting.


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## FBinNY (Jan 24, 2009)

cxwrench said:


> the chain being a link or 2 longer or shorter won't change the 'tension' on the top run of chain, where the derailleur does the shifting.


+1 

The baseline tension which is the same as the lower loop, and relatively constant regardless of chain length only happens when coasting. While pedaling - as one would be when shifting - the upper loops tension is determined exclusively by pedal pressure, which is why it's good practice to ease up during the shift.


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## cxwrench (Nov 9, 2004)

Doctor Falsetti said:


> If you look closely at our DR you can see the issue......SRAM


blah blah blah...:Yawn:


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## frdfandc (Nov 27, 2007)

Personally I'd install an in-line barrel adjuster.

The FD's on Sram systems are a bear to setup. I've ran the Force FD and shifters for 2 years without a single chain drop, but cable tension is very important. Too much, and the FD slams the chain a tad to hard, too loose and it will not up shift. 

I do all my Sram FD adjustments on a test ride. But the bike has to have an in-line barrel adjuster.


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## PoorCyclist (Oct 14, 2010)

I have got it working pretty good. As mentioned it seems to be the technique to operate lever, I found there is is a trim when downshifting (1st soft click) release some of the tension and then the second click will complete the shift, combining with some position / tension adjustment and clicking the lever a little slower there has been no dropping yet.


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## camping biker (Dec 22, 2011)

Because you're not a "real" cyclist if you don't have STI or Ergo. 








retroshift | Mud Proof Shifting. Designed by Goats! 



wesb321 said:


> Anyone remember friction shifters? Why'd we give these up again?
> 
> I agree with the cable tension and FD height diagnosis, fine tuning is so tedious but it's all the little things working as one that make the magik happen


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## camping biker (Dec 22, 2011)

Is your chain old or gritty? Almost all the chainsuck issues I ever had were due to mud, stetch, or worn chainrings coupled with short chain stays. 

Here's a magic trick if you do like STI or trigger shifters: Use a small washer to space out the inner plate and outer cage plate if your FD has a screw in the back, old style. Also, turning it just a degree in or out can help prevent chain rub on the inner or outer cog and might boost shifting to the outer ring (if turned CCW from the top). 

If you run a triple shifter with a double crank, you can use the "low" position as a trim position. Nice! 

From that picture, I would try raising the FD a tad. It's free, just a couple minutes to try it up and down and see if it works "better". FDs are always the most work to me.


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## wesb321 (Oct 1, 2011)

camping biker said:


> Because you're not a "real" cyclist if you don't have STI or Ergo.
> 
> 
> 
> ...


I keep an old set of Falcons around, I like them. I rode with 3 shifters for awhile. 2 soras and 1 friction used as a bleeder/trim for the FD I had ran the cable from the left shifter down to the friction lever then onto the FD, micro adjustments galore haha!


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## camping biker (Dec 22, 2011)

Please post a pic on my visitor page or send a link! I had thought about something like that, but never tried it. I've heard of people using those even as new factory OE items to lockout mtn bike shocks, but never seen anyone use it in line with a road shifter. Excellent! 

Epic Win Pencil Sharpener - YouTube

I am wondering why no one has made a home-made thumbie for the Rohloff hubs. Someone (jtek) is supposedly going to make one for the Shimano IGH but it only goes in the bar-end. 








https://gallery.roadbikereview.com/uploads/roadbike/425968/jamis_bike_3_bigger.jpg





wesb321 said:


> I keep an old set of Falcons around, I like them. I rode with 3 shifters for awhile. 2 soras and 1 friction used as a bleeder/trim for the FD I had ran the cable from the left shifter down to the friction lever then onto the FD, micro adjustments galore haha!


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## wesb321 (Oct 1, 2011)

camping biker said:


> Please post a pic on my visitor page or send a link! I had thought about something like that, but never tried it. I've heard of people using those even as new factory OE items to lockout mtn bike shocks, but never seen anyone use it in line with a road shifter. Excellent!
> 
> Epic Win Pencil Sharpener - YouTube
> 
> I am wondering why no one has made a home-made thumbie for the Rohloff hubs. Someone (jtek) is supposedly going to make one for the Shimano IGH but it only goes in the bar-end.



OK, when I was using this one I had 3 shifters going as well, 3 friction shifters that is. I'll have to get a pic of the falcon along with the sora and time to explain a little whats going on with it. https://forums.roadbikereview.com/3664563-post1541.html


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## camping biker (Dec 22, 2011)

If I understand right, you are running the trigger/sti shifter cable to but against the thumbie, where the cable end ball would normally be, so that the thumbie adds or drops a couple mm to the line for trim. 

I like these little cheapos. I bought some for spares on a mtb and have just kept using them because I like the zipper noise and the sweep of the shifters.







https://ecx.images-amazon.com/images/I/31WyFHm5DxL._SL500_AA300_.jpg

These work with 5-9 speed, haven't heard of 10sp use yet.


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## humble (Nov 23, 2007)

If you are using a SRAM chain, try changing to shimano or KMC. I think spec for the cage on from the big ring is 1-3 mm and you were and are ok. I have a similar issue with my SRAM Rival, but, it only began when I changed from KMC to SRAM chain. I have not switched back, but will, I was delayed because I stubornly tried changing SRAM chain models, to no avail. You can minimize the issue by making sure you have zero force on the pedals, but it can and will still occur. There are numerous documented issues with pro's having similar race day issues with their SRAM drive trains (and others to be fair, but recenlty the most famous (Andy, Fabian) are SRAM). SRAM has been very slow to address the issue if at all (IMHO). /h


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## Mahatma Kane (Oct 25, 2005)

humble said:


> SRAM has been very slow to address the issue if at all (IMHO). /h


Sram has addressed this issue on the new Red group due out next year. No one who has ridden it has reported on it yet (Supposedly some pro riders have it right now, though there is no way they would publicly criticize a sponsor's product). What's disapointing is that there are rumors saying that the new Red front derailleur will not be compatible with previous Sram shifters.


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## PoorCyclist (Oct 14, 2010)

Thanks everyone, I have gotten it to work pretty well, there is a first click (trim) on the downshift which I clicked first to release some of the tension, shifting it this way has downshifted the chain much more gently.

But I wanted to ask when setting the height, you leave the cage in the relaxed (inner ring) position and then use a penny on the big chain ring teeth right, that should be about 1mm?


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## wesb321 (Oct 1, 2011)

camping biker said:


> If I understand right, you are running the trigger/sti shifter cable to but against the thumbie, where the cable end ball would normally be, so that the thumbie adds or drops a couple mm to the line for trim.
> 
> I like these little cheapos. I bought some for spares on a mtb and have just kept using them because I like the zipper noise and the sweep of the shifters.
> 
> ...



I use a 10 sp campy cassette.


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## Kerry Irons (Feb 25, 2002)

*Height setting*



PoorCyclist said:


> But I wanted to ask when setting the height, you leave the cage in the relaxed (inner ring) position and then use a penny on the big chain ring teeth right, that should be about 1mm?


Just shift it to the big ring and observe how much clearance you have. IME it is best to have the cage just barely clear the teeth on the big ring.


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## camping biker (Dec 22, 2011)

Who do they think they are, Shimano?  re: new RED not compatible



Mahatma Kane said:


> Sram has addressed this issue on the new Red group due out next year. No one who has ridden it has reported on it yet (Supposedly some pro riders have it right now, though there is no way they would publicly criticize a sponsor's product). What's disapointing is that there are rumors saying that the new Red front derailleur will not be compatible with previous Sram shifters.


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## humble (Nov 23, 2007)

PoorCyclist said:


> ...
> But I wanted to ask when setting the height, you leave the cage in the relaxed (inner ring) position and then use a penny on the big chain ring teeth right, that should be about 1mm?


I am not a bike store tech, but that's about right, that's about where I have mine, but of course mine is not working very well and you are now in the SRAM zone of relatively higher maintenance and closely guarded secret tweaks to make things work the way they should. Good luck on this! /h


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## camping biker (Dec 22, 2011)

I guess it's just the road FD that has problems. I have a SRAM "universal" front d on my mtn bike and I like it a lot. It has worked well with a double crank, and a triple crank, with triggers, gripshift, and now friction shifters. It seemed to like being slightly higher than indicated by the little sticker that came on the right cage plate. I about threw it away before trying a different setting. I suppose the angle of the chain line vs. seat tube can have an effect on shifting.


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## PoorCyclist (Oct 14, 2010)

I do have a feeling *SRAM* stands for
*S*ome *R*epair *A*nd *M*aintenance


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## wesb321 (Oct 1, 2011)

camping biker said:


> I guess it's just the road FD that has problems. I have a SRAM "universal" front d on my mtn bike and I like it a lot. It has worked well with a double crank, and a triple crank, with triggers, gripshift, and now friction shifters. It seemed to like being slightly higher than indicated by the little sticker that came on the right cage plate. I about threw it away before trying a different setting. I suppose the angle of the chain line vs. seat tube can have an effect on shifting.




Well Shimano is the industry leader to be sure, mostly though I think it is just that we are all so used to Shimano that SRAM gets a rep since it works and looks a little different. We run into this same type of thing in the world of freewheels and cassettes when the names like Campy and Shimano are mixed as well.


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## camping biker (Dec 22, 2011)

Campy has some stuff that is compatible with some shimano stuff, but generally campy is a whole other animal. 

I had a bike (mountain bike) that was suffering from chain suck a lot. I thought maybe it was just the new chain, but the rings and cogs didn't look bad at all. I discovered it was the older Shimano rear derailleur I put on there, with the chain. It was atypical, with a weak spring in the pivot attached to the pulley cage. It seemed to shift well, but didn't pull hard enough on the chain. I found another one (Shimano Acera), with a strong spring, and it worked fine. 

If you're getting chainsuck, check your RD. It might have stuff blocking the pivots from rotating cleanly, or might have rusted/worn springs.


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