Bicycle Mechanics - Chain suck problem

A month or two ago I bought a new 2011 Rockhopper. After some ongoing chainsuck issues the LBS replaced the bike.
I've had the new one for about a month. I've been careful with the shifting and had some minor gliches with the shifting but nothing too bad.
Yesterday, the new bike started sucking the chain when downshifting from the middle to the smallest chainring.
So. I'm pedaling up a very slight rise and I downshift from the middle to the small chainring and the chain, while in the process of shifting from the middle to smallest ring, starts to stick and wrap itself around the smallest chainring. I immediately stop pedalling and I stop the bike to have a look at what's going on.
What I found was the section of chain that was bridging between the chainrings was firmly stuck. This segment was about 3 inches long. One end of the segment was stuck to a tooth on the middle ring, and the other end of the segment was firmly stuck to a tooth on the small ring. This segment was under noticable tension. It took some prying to get it unstuck.
I was not pedalling hard when this happened. In fact, I have never really put a lot of torque on the pedals of this bike. It's nearly new and it hasn't seen much off-road use. It's been ridden rather mildly.

Has anyone ever seen this kind of condition, or know why it could be doing this?
I'm guessing that one or both chainrings could be out-of-spec, with excessively deep valleys between the teeth, or the teeth could be too tall. I don't see how else the chain could get trapped while straddling the two rings.

This is the second identical Rockhopper that has done this to me. I talked to a customer rep when the first bike acted this way and he said he knew of no ongoing problems with 2011 Rockhoppers.

The LBS was closed today and it is about an hour's drive away. Looks like I have no choice but to return this bike also.

Try this, it solved my problems with one of my kid's mountain bike.

http://www.gvtc.com/~ngear/whatis.html (http://www.gvtc.com/%7Engear/whatis.html)

Edit: On second thought, I think that you are speaking about something else and this would be no help to you.

This may not qualify as true chainsuck, which occurs when the chain jams between the chainstay and chainring.

Your chain is doesn't seem to like the distance between two chainrings. Perhaps one of the chainrings is installed backwards, providing more space than designed. Or you might have a bent or hooked tooth which is not allowing the chain to disengage properly during the shift. Just guessing...

bump

Chain suck is almost always related to a bent or damaged tooth on the chainrings. And the damage can be quite small. Sometimes almost too small to see The chain hangs up on the tooth and won't release which is what happened to you.

Bent and damaged teeth aren't the manufacturers fault and are almost always related to operator error. A bad shift where you are grinding the rings or a shift made under too much tension can put a very small burr on the tooth. Look for scrape marks on the inside of the ring and then feel for protrusions. You can file them off and the chain suck should stop.

I suspect that you may need a cable adjustment too. It's been about a month and I'll bet you've had some balky shifting from the inner ring to the middle one. The kind where the chain just doesn't seem to want to go up to the middle ring. The chain just grinds against the ring and then finally jumps up. It may go the other way too, where the middle ring just doesn't want to let the chain move over and the chain is hovering on the edge of the middle ring. All this grinding can put a burr on the ring and lead to chain suck.

You should have brought the bike back with the chain in the "stuck" condition so the LBS could see it for themselves.

As Cycocommute says it could be caused by a very slightly bent chainring, but there are other causes.

Given the age of your bike, and that it occurs only during the downshift, I suspect it's something else. You didn't say, but have you been riding in mud, wet or fine dust?

If so, I believe your suck is caused by internal friction within the chain, and is analogous to how fishing reel overruns the line when casting without enough reel tension.

Sorry the answer is long, but read it and you'll find the solution easy and cheap.

-----

All chains have a bit of internal friction, and wouldn't unwind from the bottom of the ring except for their weight and the tension provided by the RD. When you ride in mud with no lube, or dry lubes, water wicks into the spaces between the plates, carrying fine silt. Then it evaporates leaving the silt behind (think mud flats). Eventually this silt builds up enough to increase the friction between the plates making the chain stiffer.

With the added internal friction it takes greater tension in the lower loop to pull the chain off the rings. On the outer ring, the RD might provide it, but as you move to smaller rings, the RD tension is less, which is why suck is almost reported in inner chainrings.

The reason it's most likely to suck during the shift because as the section of chain in transition from the larger to smaller ring comes around and releases from the larger ring, there's extra slack generated and it takes a bit of time for the RD to take it up. With no tension to pull it off the ring, the chain stays wrapped around it - chainsuck.

Solution, remove and wash your chain thoroughly. If it doesn't have a master link, you can do it on the bike. Make sure to do a thorough job with multiple rinses until it rinses clean. Now dry it completely with a hair dryer or a solar oven (a car parked in the sun with one window cracked open 1"). Now lube your clean dry chain with a good wet lube that won't wash out. (Yes - I have a bias here, as evidenced by the site below my signature) Wet lube prevents chain suck by keeping the internal spaces within the chain filled so water can't wick in.

If you've read this far, I'll bet you 2 beers to 1 that you'll 100% solve the chainsuck problem if you follow the above wash/lube instructions to the letter. If you're near any Chain-L dealer, wash your chain, dry it and visit them for a free test of Chain-L (email me first so I can arrange it) and I'll bet 3 beers you'll never deal with this issue again.

As Cycocommute says it could be caused by a very slightly bent chainring, but there are other causes.

Given the age of your bike, and that it occurs only during the downshift, I suspect it's something else. You didn't say, but have you been riding in mud, wet or fine dust?

If so, I believe your suck is caused by internal friction within the chain, and is analogous to how fishing reel overruns the line when casting without enough reel tension.

Sorry the answer is long, but read it and you'll find the solution easy and cheap.

-----

All chains have a bit of internal friction, and wouldn't unwind from the bottom of the ring except for their weight and the tension provided by the RD. When you ride in mud with no lube, or dry lubes, water wicks into the spaces between the plates, carrying fine silt. Then it evaporates leaving the silt behind (think mud flats). Eventually this silt builds up enough to increase the friction between the plates making the chain stiffer.

With the added internal friction it takes greater tension in the lower loop to pull the chain off the rings. On the outer ring, the RD might provide it, but as you move to smaller rings, the RD tension is less, which is why suck is almost reported in inner chainrings.

The reason it's most likely to suck during the shift because as the section of chain in transition from the larger to smaller ring comes around and releases from the larger ring, there's extra slack generated and it takes a bit of time for the RD to take it up. With no tension to pull it off the ring, the chain stays wrapped around it - chainsuck.

Solution, remove and wash your chain thoroughly. If it doesn't have a master link, you can do it on the bike. Make sure to do a thorough job with multiple rinses until it rinses clean. Now dry it completely with a hair dryer or a solar oven (a car parked in the sun with one window cracked open 1"). Now lube your clean dry chain with a good wet lube that won't wash out. (Yes - I have a bias here, as evidenced by the site below my signature) Wet lube prevents chain suck by keeping the internal spaces within the chain filled so water can't wick in.

If you've read this far, I'll bet you 2 beers to 1 that you'll 100% solve the chainsuck problem if you follow the above wash/lube instructions to the letter. If you're near any Chain-L dealer, wash your chain, dry it and visit them for a free test of Chain-L (email me first so I can arrange it) and I'll bet 3 beers you'll never deal with this issue again.

Sorry but you are way off base. Chain suck only happens on downshifts. Given that the chain is lifted off the inner gears during an upshift by the larger cog and that the chain is under tension, I can't see how you would have chain suck on an upshift even if the tooth were bent almost 90 degrees. The tooth would probably sheer off before it would grab the chain and hold it on the smaller cog. Plus you would have been experiencing chain suck on the downshifts long before the tooth could be sheered off anyway.

This is a bike that is a month old. I doubt that even in a month of hard riding in the mud, you could have the kinds of build up of debris on the chain that would cause the kind of internal frictions you are talking about. And the internal friction of the chain isn't going to be an issue with respect to the rear derailer either. The rear derailer spring on a month old bike should be able to deal with that kind of friction easily and pull the chain off. The kind of slack you are talking about generating in the chain is something that would be evident in a years old derailer, not a nearly new one.

If you had read the post, you'd see that I said that the symptom was sucking wen shifting from large to small chainring, or downshifts.

Anyway, I've no interest in debating the theoretical, I'm not trying to convince you of anything. You have your theory & I have mine and readers are free to decide who to believe, or try both our suggestions seeing what works. As I repeat ad infinitum, the proof of the pudding is in the eating.

In any case my bet with the OP stands, My solution is free, and the most he can lose is the chainsuck and a beer. If I'm wrong he still has a problem, but the 2 beers might help it go down easier.

What I found was the section of chain that was bridging between the chainrings was firmly stuck. This segment was about 3 inches long. One end of the segment was stuck to a tooth on the middle ring, and the other end of the segment was firmly stuck to a tooth on the small ring. This segment was under noticable tension. It took some prying to get it unstuck.

^What would cause this?^ Shouldn't a power transmission system be designed to not let something like this happen? Makes me think that maybe the chainrings used on these bikes could be an issue.

What I found was the section of chain that was bridging between the chainrings was firmly stuck. This segment was about 3 inches long. One end of the segment was stuck to a tooth on the middle ring, and the other end of the segment was firmly stuck to a tooth on the small ring. This segment was under noticable tension. It took some prying to get it unstuck.

^What would cause this?^ Shouldn't a power transmission system be designed to not let something like this happen? Makes me think that maybe the chainrings used on these bikes could be an issue.

This is a different problem, not what people usually refer to as chainsuck,

When you shift under load, either the front or the rear, the chain can be forced down on the new chainring, before releasing from the older obe. This puts bigtime twisting forces on the chain an spreads the plates, which is why you have to use non-spliceable chains with any modern gated shifting system. This is one of the most common causes of chain breakage in mtb.

Most folks see this in the back, and don't notice other than maybe a loud crunching sound, because the upper loop is under tension and rips the jammed chain free. It happens less often on the front because it's harder to shift under load, but it can, and when it does the low tension on the lower loop can't pull it free.

The solution is very simple, Do not shift under heavy load, Plan ahead and shift the front while you're still running light pedal pressure, or can at least ease up for a well timed second through the shift.

BTW- I'd take a moment to run the chain through your fingers feeling, or looking for any twisted or spread links. If you see any replace the chain before it breaks.

As for designing the system so it can't happen, that's a trade off, the gated shifting (hyperglide) that makes this possible is also what makes for otherwise smoother faster shifting. Years ago, before hyperglide, this wasn't an issue, but shifting was much more sluggish, and totally impossible uder any kind of load. You win some, you lose some, but most who've seen both the old and the new agree the new is better.

This is my opinion and my opinion only. I'm not an expert, but this is what I would do.
I would NOT do any adjusting or mechanical work on this bike. You will give the LBS or manufacturer a way out. They could blame you. The bike (s) are to new to have this problem, both of them. No coincidence in my opinion. Two exact model bikes. Like I said before, bring it in with the chain jambed up so they can see first hand what the problem is. It's their responsibility to make it right.
Maybe they need to bring in a company rep. 2 bikes same shop. Strange.
It could be a bad run of chains. Stiff links etc.
Also, Google and check out the reviews on this bike. Seems like others have had this or a similar problem?

What I found was the section of chain that was bridging between the chainrings was firmly stuck. This segment was about 3 inches long. One end of the segment was stuck to a tooth on the middle ring, and the other end of the segment was firmly stuck to a tooth on the small ring. This segment was under noticable tension. It took some prying to get it unstuck.

^What would cause this?^ Shouldn't a power transmission system be designed to not let something like this happen? Makes me think that maybe the chainrings used on these bikes could be an issue.

A twisted tooth - possibly 2 twisted teeth - is about the only way this could happen. The chain needs to release from the teeth smoothly for the chain to drop from one ring to the other. Your chain hung up on a badly twisted tooth as it was dropping and as it caught the little ring, it bound up between the rings, probably twisting and bending both rings in the process.

FBinNY is partially right - but only partially - about shifting under tension. I suspect that one of the rings was damaged when you upshifted earlier under a lot of torque - it happens. Because of the way that bicycle derailers work, it's easy to force an upshift and cause damage.

As you were downshifting, the chain released from the middle ring to the inner ring but caught on the damaged tooth. Putting tension on the chain like you are while riding up hill and trying to downshift, trapped the chain between the two rings, further bending both. Now your chain is stuck and can't go forward - i.e. release from the large ring - and can't go back - i.e. climb back up on the large ring. There's not enough tension in the rear derailer spring to pull the chain off the now bent teeth and you end up with a classic case of chain suck. Yours is just particularly extreme.

To avoid this, you should ease up on the pedal pressure slightly while you shift either up or down. It doesn't have to be much. Just enough so that things shift smoothly.


If you had read the post, you'd see that I said that the symptom was sucking wen shifting from large to small chainring, or downshifts.

Anyway, I've no interest in debating the theoretical, I'm not trying to convince you of anything. You have your theory & I have mine and readers are free to decide who to believe, or try both our suggestions seeing what works. As I repeat ad infinitum, the proof of the pudding is in the eating.

In any case my bet with the OP stands, My solution is free, and the most he can lose is the chainsuck and a beer. If I'm wrong he still has a problem, but the 2 beers might help it go down easier.

Perhaps you should read your own posts:


Given the age of your bike, and that it occurs only during the downshift, I suspect it's something else.

The age of the bike has nothing to do with it.


This is a different problem, not what people usually refer to as chainsuck,

When you shift under load, either the front or the rear, the chain can be forced down on the new chainring, before releasing from the older obe. This puts bigtime twisting forces on the chain an spreads the plates, which is why you have to use non-spliceable chains with any modern gated shifting system. This is one of the most common causes of chain breakage in mtb.

Most folks see this in the back, and don't notice other than maybe a loud crunching sound, because the upper loop is under tension and rips the jammed chain free. It happens less often on the front because it's harder to shift under load, but it can, and when it does the low tension on the lower loop can't pull it free.

The solution is very simple, Do not shift under heavy load, Plan ahead and shift the front while you're still running light pedal pressure, or can at least ease up for a well timed second through the shift.

BTW- I'd take a moment to run the chain through your fingers feeling, or looking for any twisted or spread links. If you see any replace the chain before it breaks.

As for designing the system so it can't happen, that's a trade off, the gated shifting (hyperglide) that makes this possible is also what makes for otherwise smoother faster shifting. Years ago, before hyperglide, this wasn't an issue, but shifting was much more sluggish, and totally impossible uder any kind of load. You win some, you lose some, but most who've seen both the old and the new agree the new is better.

This is absolutely chain suck. The chain sticks to the rings and is sucked into the gap between the bike frame and the chainwheels. It's not caused by the chain but by damaged teeth on the crankset that won't release the chain. if sknhgy inspects the crank where the problem occurred, he'll find bent teeth on both rings. Given that he managed to stick the chain to both inner and middle rings, I suspect that he'll find bent rings too.

You are correct about it be an issue caused by shifting under tension but you are just wrong about the specifics.

Dumb question.
What kind of steel are these parts made of to be able to be bent and twisted under load?
I take it this is not a big box store bike, this should not happen to a quality bike.

Dumb question.
What kind of steel are these parts made of to be able to be bent and twisted under load?
I take it this is not a big box store bike, this should not happen to a quality bike.

The parts could be steel or aluminum, depending on the component level. But the tolerances on either are pretty small. I've had chains suck on to burrs that are difficult to see. I've also folded tandem chainwheels in half because of botched shift.

In sknhgy's case, I suspect that the chainwheels may have bent because of the chain being jammed on a chainring tooth. It takes less than you'd imagine to do it. The force of the rider's weight is focused on a very tiny spot. Small area + large load = lots of local force.

Believe me, I'm not trying to be argumentative because my experience with deraileuers is nil.
Why doesn't stuff like this happen to Lance Armstrong. These guys must beat the ***** out of their equipment?
This is not a cheap department store bike. I just have a hard time understanding and having to accept the fact that this equipment can fail under everyday situations.
It's like saying I just bought a new car, stepped on the gas to hard and the transmission fell out. Not once, but twice.

I've never had a problem like this on any other bike.

Believe me, I'm not trying to be argumentative because my experience with deraileuers is nil.
Why doesn't stuff like this happen to Lance Armstrong. These guys must beat the ***** out of their equipment?
This is not a cheap department store bike. I just have a hard time understanding and having to accept the fact that this equipment can fail under everyday situations.
It's like saying I just bought a new car, stepped on the gas to hard and the transmission fell out. Not once, but twice.

It doesn't happen to the pros because they have a factory and a bunch of mechanics backing them up. Their bikes probably never see enough wear and tear to on the components to have much damage occur. They are also all very skilled riders and know how to shift so as to not damage the equipment.

To use your car analogy, some riders - not saying you, sknhgy - drive like they got a new car, threw the shift lever from 5th at 80 mph into reverse and then wonder why their transmission is laying on the ground behind them. Then turn around and blame the manufacturer for not designing the car to go from 5th to reverse at 80 mph.


I've never had a problem like this on any other bike.

It happens. Like I said before, you'd be amazed at how small a burr on a chain ring has to be to catch on a gear tooth. Getting the chain sucked across two rings and stuck on two different teeth is a bit rare...I haven't heard of it happening...but I can see how it could happen. And I can envision the damage to the chainrings.

Digging a bit further, the Rockhopper comes with an Alivio 8 speed crank but a 9 speed cassette. While there shouldn't be a problem with that combination, the 8 speed's teeth may be wider. That would make any burr problem worse. Talk to the shop and see if you can swap the crank or get 9 speed chainwheels. Work a deal with them but be reasonable. Since you've had this issue with another crank, it may be part operator and part equipment. See if they'll go halvsies on a new chain ring set.

Believe me, I'm not trying to be argumentative because my experience with deraileuers is nil.
Why doesn't stuff like this happen to Lance Armstrong. These guys must beat the ***** out of their equipment?

Stuff like this DOES happen to the pros. Andy Schleck's chain got jammed in last year's Tour de France... during a crucial moment, I might add. Lance had a pedal fail on him while climbing the alps. It happens less often to them because their equipment is replaced more often, but it does happen.

As Cycocommute says it could be caused by a very slightly bent chainring, but there are other causes.

Given the age of your bike, and that it occurs only during the downshift, I suspect it's something else. You didn't say, but have you been riding in mud, wet or fine dust?

If so, I believe your suck is caused by internal friction within the chain, and is analogous to how fishing reel overruns the line when casting without enough reel tension.

Sorry the answer is long, but read it and you'll find the solution easy and cheap.

-----

All chains have a bit of internal friction, and wouldn't unwind from the bottom of the ring except for their weight and the tension provided by the RD. When you ride in mud with no lube, or dry lubes, water wicks into the spaces between the plates, carrying fine silt. Then it evaporates leaving the silt behind (think mud flats). Eventually this silt builds up enough to increase the friction between the plates making the chain stiffer.

With the added internal friction it takes greater tension in the lower loop to pull the chain off the rings. On the outer ring, the RD might provide it, but as you move to smaller rings, the RD tension is less, which is why suck is almost reported in inner chainrings.

The reason it's most likely to suck during the shift because as the section of chain in transition from the larger to smaller ring comes around and releases from the larger ring, there's extra slack generated and it takes a bit of time for the RD to take it up. With no tension to pull it off the ring, the chain stays wrapped around it - chainsuck.

Solution, remove and wash your chain thoroughly. If it doesn't have a master link, you can do it on the bike. Make sure to do a thorough job with multiple rinses until it rinses clean. Now dry it completely with a hair dryer or a solar oven (a car parked in the sun with one window cracked open 1"). Now lube your clean dry chain with a good wet lube that won't wash out. (Yes - I have a bias here, as evidenced by the site below my signature) Wet lube prevents chain suck by keeping the internal spaces within the chain filled so water can't wick in.

If you've read this far, I'll bet you 2 beers to 1 that you'll 100% solve the chainsuck problem if you follow the above wash/lube instructions to the letter. If you're near any Chain-L dealer, wash your chain, dry it and visit them for a free test of Chain-L (email me first so I can arrange it) and I'll bet 3 beers you'll never deal with this issue again.

OK. The problem got worse after I lubed the chain with a dry wax lube, then spent a couple of days on the local gravel-screening covered trail. After reading all the posts I brushed the chain then lubed it with Break free. That helped, but didn't clear it up completely.
I removed the chain and soaked and swished it in a jar of mineral spirits. Then dried it. Then I soaked and swished it in a jar of laquer thinner, then hung it in the sun to dry while I went for a ride.
Then I soaked and swished it in a jar of 30W/mineral spirits mix. It is hanging now. I will put it back on the bike and take it for a ride in a day or so. Kind of busy right now. Will report back then.

Before I did all this cleaning, and after I lubed it with Break free, I did get the chain to jam up one time and I was going to take it to the LBS in that condition, but when I touched it to feel for tension the chain came free from the chainrings.

It happened again - and it has happened a few times since the last post. The chain stuck like this so I walked the bike home, loaded it up, and took it to the LBS. I said enough is enough. Here's what it looks like when it happens:
212420
I am waiting to hear back from the shop owner. He is going to contact the Specialized customer rep. I just can't understand this. I've never had a bike do this before. I currently own 2 other, much cheaper mountain bikes and both of them work flawlessly. I hate it when you spend a lot of cash to get something better but you end up with more problems.
Thanks for letting me rant.

Yea, that's bad.

I've had this happen 3-4 times in the last 5-6 months, is this typical "chainsuck" or some severe form of the disease?

Let us know what the LBS and rep has to say.

They are putting a new crankset on it. That makes sense to me. What else can it be but bad chainrings?

This has been happening to my compact crank. I've had to replace both front and back derailleurs because the chain bent both (oh and had to replace my brand new chain).

I did find some small burrs on the large chain ring. I sanded it down smooth. I always carefully lube my chain.

I'm thinking I need to polish the large chain ring.

This a 1.5 year new Fuji ACR 2.0 but I have about 3k on it.

And it happened again today. It looked just like the picture above. I was looking for it, so it didn't jamb too bad. and when I got off to check it out the chain dropped down on its own.

I was looking for it, so it didn't jamb too bad. and when I got off to check it out the chain dropped down on its own.

I got to the point where I was watching for it on every downshift, and I was staying in the middle chainring to avoid the problem. The last time it happened was when I took the pic, and it had jammed tight.
The bike shop has had it for 9 days now. I think it's time for another call.

I don't want to start a fresh war on this subject, but there are 3 main causes of chainsuck.

1- Hard shifting under power, jamming the chain 1/2 on one ring and half on the other. This is characterized by needing lots of force to pull it apart, and can damage both the chain or chainring. While this looks and acts like chainsuck, I prefer not to call it that because it's isolated, and obvious.

2- Burred, nicked or bent chainring teeth catching the chain and raising the force needed to pull it off. Often easily fixed by dressing with a file, though more extreme cases call for chainring replacement.

3- internal friction within the chain, requiring more force to straighten each link as the chain unfurls. This is more like the overrunning of fishing line on a reel when there isn't enough tension on the line. This kind of suck will often self-clear if you have good reflexes and stop pedaling or backpedal a bit.

If you've tried everything and still have intermittent, unpredictable chainsuck, re-read my post #7. Feel free to PM me if you want to test my theory, and I'll send you a free sample of oil and instructions for how to get ride of the problem for good.

The offer is good for anybody experiencing chainsuck, not attributable to extremely worn or otherwise damaged chainrings.

As I said earlier, the only thing you have to lose is your chain suck problem.

I've put about 60 miles on since the last incident, so I think I might have this problem solved. I've done the following:

1. Sanded each tooth on my large chainring (I have a 50/34). Several teeth needed to be filed then sanded smooth. I found several burrs.
2. Oiled the chain-ring with a wet oil. Not dripping, but wet. After each ride (20+ miles) I wipe down and re-oil... only takes seconds.
3. No hard down-shifting off the large chainring. I always watch it shift. This might be the best of the 3. I don't like talking my eyes off the road to shift, but the alternative is potentially dangerous and expensive.

3. No hard down-shifting off the large chainring. I always watch it shift. This might be the best of the 3. I don't like talking my eyes off the road to shift, but the alternative is potentially dangerous and expensive.

You don't have to watch the shift, just lighten the pedal pressure to reduce the tension in the chain.

You don't have to watch the shift, just lighten the pedal pressure to reduce the tension in the chain.

That's true. I'm getting more comfortable... being careful. Another 20 miles today without issue.

I can hear the chain dropping now. I has a distinctive sound. Course the crushing chain suck has one too. ;)

I don't think there is anything wrong.You need to let up off of the pedals so it can shift off of the big ring.If you put to much tension on the pedals while shifting,it can't come off of the gear.

I thought chain suck is when the chain starts to climb on top of itself?

You said the problem got better after one of your chain cleanings. What kind of lube were you using when you had the first bike? The wax? I DO NOT like wax. When you get your bike back don't use that nasty stuff. Clean the chain with a high quality degreaser and a special chain cleaning tool. Let it dry. Then put the lightest non wax lube you can find on it. I DO NOT like wax. Last time I talked to a bud who had problems like yours, he was using chain wax.

Break free is too heavy for your use.

You said the problem got better after one of your chain cleanings. What kind of lube were you using when you had the first bike? The wax? I DO NOT like wax. When you get your bike back don't use that nasty stuff. Clean the chain with a high quality degreaser and a special chain cleaning tool. Let it dry. Then put the lightest non wax lube you can find on it. I DO NOT like wax. Last time I talked to a bud who had problems like yours, he was using chain wax.

Break free is too heavy for your use.

You may not like wax but it has nothing to do with this problem. Chain suck isn't a lubrication problem. It's a damaged chainring problem or, as I've suggested earlier, a mismatched chain/chain ring problem. What lubricant you use or have used has zero effect on chainsuck.

You may not like wax but it has nothing to do with this problem. Chain suck isn't a lubrication problem. It's a damaged chainring problem or, as I've suggested earlier, a mismatched chain/chain ring problem. What lubricant you use or have used has zero effect on chainsuck.

I have to agree with this post. I've ridden bikes all my life and have never had this problem. Something is up with the chainrings and/or chain. It would take a very, very non-robust design for a problem like this to be caused by lube. I know how to ride, I know how to shift, I know how to maintain a bike. This problem has occurred on normal, as well as the most gentle of shifts.
Why can't the chainrings be out-of-spec? Any number of factors could cause parts to be made out-of-tolerance. It happens all the time. I think these "brand-new" chainrings are, for some reason, acting like very old, highly worn chainrings. I ain't no Sheldon Brown, but that is my opinion. I would love to get the chainrings and a blueprint in front of me. The fact that it has happened on two identical bikes that almost had to have come off the same assembly line during the same run of the product makes me think they had a shipment of bad chainrings during that assembly operation. I got a call today that the LBS is finished with the bike. They put on a new crankset. I am going to pick it up tomorrow and hit the trails.

You may not like wax but it has nothing to do with this problem. Chain suck isn't a lubrication problem. It's a damaged chainring problem or, as I've suggested earlier, a mismatched chain/chain ring problem. What lubricant you use or have used has zero effect on chainsuck.

Do you think it is happenstance that the conditions improved immediately after he cleaned the chain?

My second question is why would he be experiencing chain ring damage on two essentially new bikes?

When I bought my Trek 1500 and my Specialized Tarmac they both had chain suck problems within the first few hundred miles. A thorough degreasing and a VERY light coat of Pedros Dry Lube and they both functioned flawlessly. Now every new chain I get gets degreased immediately.

I call it chainsuck when the chain gets pulled between the chainstay and the inner chainring on the underside.

Chain suck can most assuredly be a lubrication issue. When they get too gummed up, the links don't move as freely as they should which can have the same effect as a damaged link. My experiences with chain wax on bicycles tells me that it can have a gumming effect.

Do you think it is happenstance that the conditions improved immediately after he cleaned the chain?

Yes, I do think that it's happenstance. Especially considering that cleaning the chain didn't fix the problem. Check the later posts.


My second question is why would he be experiencing chain ring damage on two essentially new bikes?

When I bought my Trek 1500 and my Specialized Tarmac they both had chain suck problems within the first few hundred miles. A thorough degreasing and a VERY light coat of Pedros Dry Lube and they both functioned flawlessly. Now every new chain I get gets degreased immediately.

I call it chainsuck when the chain gets pulled between the chainstay and the inner chainring on the underside.

Read my posts. I have two suggestions on the problem. One is chainring damage. The other is a mismatched 8 speed chainring and a 9 speed chain. It shouldn't cause a problem but it certainly wouldn't make things better.

Ring damage could happen the first time the front derailer is shifted. Damage isn't wear. Damage can happen at any time. A missed shift or a shift under pressure or any number of other scenarios could result in burrs on the chainring teeth. Couple that with a tooth width that is a little wider and chain suck - which I know what it is, how it happens and how to fix it, thank you very much:rolleyes: - is almost inevitable.


Chain suck can most assuredly be a lubrication issue. When they get too gummed up, the links don't move as freely as they should which can have the same effect as a damaged link. My experiences with chain wax on bicycles tells me that it can have a gumming effect.

See skngy's post above and apply Occam's Razor. For a lubricant to overcome the tension inherent in the drivetrain, the lubricant would make moving the chain around the drivetrain nearly impossible. Wax based lubricants don't do that. Not in my experience anyway.

See skngy's post above and apply Occam's Razor. For a lubricant to overcome the tension inherent in the drivetrain, the lubricant would make moving the chain around the drivetrain nearly impossible. Wax based lubricants don't do that. Not in my experience anyway.

Let's agree to disagree here.


I will say this about your last comment...and this is just me thinking out loud for a moment. I get myself in trouble when I try to speak of things mechanical and physical but I'll try. There is a point in the down shift where a portion of the chain along the bottom just behind the small ring relaxes a bit relatively speaking. It's easy to see while downshifting with the bike on the stand. If you have a couple of sticky links, thay can and will get sucked in.

This link touches on how a dirty or gummed up chain can contribute.

http://www.fagan.co.za/Bikes/Csuck/

Here's an excerpt.

"There are some obvious issues which can cause chain-suck such as damage to chain-rings, teeth, or the chain. Tight chain links caused by damage, or by poorly maintained chains packed with dried mud, can also cause chain-suck. Clearly, these problems can directly cause snagging of the chain. "

Anything I have ever read and my own experiences tell me that a stiff chain can contribute to chain suck.


For the OP.

I tend to be simple minded. When I troubleshoot a problem, I start by applying the simplest solutions first. In the past when I have had chain suck issues, I have THOROUGHLY cleaned and DEGREASED my chain, then put a LIGHT coat of VERY LIGHT lube on it. This has ALWAYS remedied the problem.

If you shift the way you have described yourself shifting, then I don't think it is likely you would have damaged two bikes so early on. If it was an issue of tolerances or mismatches, I would think Specialized would know something about it by now and that we would have heard from other Rockhopper owners by now.

Wax and Break Free attact and hold dirt particles.

I am curious as to what they replaced on your bike this last time and what they replaced it with. Good luck and keep us posted.

Let's agree to disagree here.


I will say this about your last comment...and this is just me thinking out loud for a moment. I get myself in trouble when I try to speak of things mechanical and physical but I'll try. There is a point in the down shift where a portion of the chain along the bottom just behind the small ring relaxes a bit relatively speaking. It's easy to see while downshifting with the bike on the stand. If you have a couple of sticky links, thay can and will get sucked in.

This link touches on how a dirty or gummed up chain can contribute.

http://www.fagan.co.za/Bikes/Csuck/

Here's an excerpt.

"There are some obvious issues which can cause chain-suck such as damage to chain-rings, teeth, or the chain. Tight chain links caused by damage, or by poorly maintained chains packed with dried mud, can also cause chain-suck. Clearly, these problems can directly cause snagging of the chain. "

Anything I have ever read and my own experiences tell me that a stiff chain can contribute to chain suck.


Note that the author says it's due to a "poorly maintained chain packed with dried mud". Grit in the chain could cause binding and could make the chain hang up on the rings. But that's not the case here. It's a new bike and, from sknhgy's pictures, not a particularly dirty one. Grit isn't a problem with wax lubricants either. Nothing to stick to. Wax absolutely does not attract nor hold dirt. Oil based lubricant do but not wax. And the wax is soft enough that any pressure on it would make it move out of the way and not bind.

Note that the author says it's due to a "poorly maintained chain packed with dried mud". Grit in the chain could cause binding and could make the chain hang up on the rings. But that's not the case here. It's a new bike and, from sknhgy's pictures, not a particularly dirty one. Grit isn't a problem with wax lubricants either. Nothing to stick to. Wax absolutely does not attract nor hold dirt. Oil based lubricant do but not wax. And the wax is soft enough that any pressure on it would make it move out of the way and not bind.

Sheldon brown says this:

Chain suck

Chain suck occurs primarily when downshifting under load from the middle to the smallest chainring. The bottom run of the chain may not immediately disengage from the middle ring, and can get carried upward until it wedges betwixt the chainwheels and the right chainstay.
This jams the crankset. Since you probably wouldn't have been shifting to the granny if you weren't already climbing, the sudden lock-up of the drive train deprives you of what little momentum you had, and you are very likely to stall and fall. Chain suck is commonly caused by bent chainring teeth, dirty chains, or, occasionally, burrs on the teeth of new chainwheels.

Sheldon brown says this:

Chain suck

Chain suck occurs primarily when downshifting under load from the middle to the smallest chainring. The bottom run of the chain may not immediately disengage from the middle ring, and can get carried upward until it wedges betwixt the chainwheels and the right chainstay.
This jams the crankset. Since you probably wouldn't have been shifting to the granny if you weren't already climbing, the sudden lock-up of the drive train deprives you of what little momentum you had, and you are very likely to stall and fall. Chain suck is commonly caused by bent chainring teeth, dirty chains, or, occasionally, burrs on the teeth of new chainwheels.


The bike and chain in the pic looked dirty enough to me to cause chain suck.

The bike and chain in the pic looked dirty enough to me to cause chain suck.

Just a note about dirty chains. This has happened to me many times on my road bike and my chain and chain ring are very clean.

I'm on about 100 miles without an issue. Sanding, filing and lightly oiling the chain ring is working for me (oh and lightly downshifting).

Sheldon brown says this:

Chain suck

Chain suck occurs primarily when downshifting under load from the middle to the smallest chainring. The bottom run of the chain may not immediately disengage from the middle ring, and can get carried upward until it wedges betwixt the chainwheels and the right chainstay.
This jams the crankset. Since you probably wouldn't have been shifting to the granny if you weren't already climbing, the sudden lock-up of the drive train deprives you of what little momentum you had, and you are very likely to stall and fall. Chain suck is commonly caused by bent chainring teeth, dirty chains, or, occasionally, burrs on the teeth of new chainwheels.

This is one of those rare cases where Brown is wrong. The problem isn't with disengagement of the chain from the middle ring but with too much engagement of the inner ring. There's also a lot of 'bounce' associated with the change from middle ring to the inner ring that results in the chain not being pulled off the lowest teeth (first to engage the chain during a shift) of the inner wheel. Look at the picture below:

http://www.bikeforums.net/attachment.php?attachmentid=212420&d=1311891495

The chain is fully engaged with the inner ring...so much so that the inner wheel has just about wrapped the chain 360 degrees around the wheel. This indicates that the chain isn't coming off the bottom of the inner wheel and is hung up on something. That something is, likely, a bent or damaged tooth. Burrs, by the way, don't necessarily only occur on new rings. Chains are fully capable of developing burrs on rings as a natural part of the shifting process.

The chain, by the way, is cleaner than most but not a clean as some. It certainly isn't 'packed with dried mud'. It is dusty as you'd expect any mountain bike chain to be but not nearly enough to cause chainsuck from stuff in the chain.

You should write a book since you know so much...and a professional mechanic. Starting with the most complicated solution first would be good for the bottom line.

The cranks now say Shimano, and it has new chainrings. I haven't had a chance to ride it yet, other than around the parking lot.

At one point I removed the chain and soaked it in MS, then I soaked it in laquer thinner, then I soaked it in MS/30W, about a 3 or 4 to 1 ratio.
It still had the problem.

I am so tired of dealing with this. All I want is a dang bike that works like a bike, that I can take out and ride. Just looking at it now and comparing it to the picture I posted, I can see that there are new, deep nicks on the chainstay and the FD needs adjusting.
I'm tired and I'll look at it tomorrow.

I rode the bike today. No chainsuck problems. However, in low gear the chain rubs the inside of the derailler cage. I thought, no problem - I'll just adjust the low limit screw. Well, the limit screw was backed out till it was just hanging there and not limiting derailler movement. In other words, all the adjustment has been taken up and the cage still rubs the chain in low gear. In addition to that, when you shift from the small to the middle chainring you have to go way past the middle indent, almost shifting onto the large ring before the chain will engage the middle ring.
I don't know if I should just live with it this way, or pitch a fit and tell them once and for all this bike ain't right and I want my money back. I do know I'm tired of dropping it off at the LBS for them to work on.

I rode the bike today. No chainsuck problems. However, in low gear the chain rubs the inside of the derailler cage. I thought, no problem - I'll just adjust the low limit screw. Well, the limit screw was backed out till it was just hanging there and not limiting derailler movement. In other words, all the adjustment has been taken up and the cage still rubs the chain in low gear. In addition to that, when you shift from the small to the middle chainring you have to go way past the middle indent, almost shifting onto the large ring before the chain will engage the middle ring.
I don't know if I should just live with it this way, or pitch a fit and tell them once and for all this bike ain't right and I want my money back. I do know I'm tired of dropping it off at the LBS for them to work on.

That sounds like a spindle length or spacer issue. The drive side of the bottom bracket isn't far enough outboard so the crank is too close to the frame. They likely just used the old bottom bracket and that may not be the same for the two different cranks. I really, really hate to say this but you'll have to take it back. Or learn how to fix it yourself.

Fixing it yourself does a few things. First it makes the wait for repairs much shorter. Like days shorter. Second it gives you a sense of accomplishment. You fixed it and you'll ride it. Third it makes it so that you can go on the Bikeforums and pontificate...once you've ruined enough parts:eek::rolleyes:;)

That sounds like a spindle length or spacer issue. The drive side of the bottom bracket isn't far enough outboard so the crank is too close to the frame. They likely just used the old bottom bracket and that may not be the same for the two different cranks. I really, really hate to say this but you'll have to take it back. Or learn how to fix it yourself.

Fixing it yourself does a few things. First it makes the wait for repairs much shorter. Like days shorter. Second it gives you a sense of accomplishment. You fixed it and you'll ride it. Third it makes it so that you can go on the Bikeforums and pontificate...once you've ruined enough parts:eek::rolleyes:;)

The first thing I noticed is that the chainrings seem to be almost brushing the frame. Very little clearance.
OK. If I did decide to fix it, what do I do? Seems like it needs a spacer, but what and where?
If it needs a different BB, I sure as heck don't think I should pay for that.

I really don't want to drop this bike back off at the LBS. Right now it is sitting in my basement and I have removed my grips, seat, and bottle cages. I have written a letter to the Specialized Service Dept. I am going to call them when they open and tell them the situation. I will ask that they call the LBS and see if they can come up with a solution. I don't like being put in the position of being a PITA to the LBS. I'm putting the ball in their court. But, at this point I am ready to drop the bike off and demand a refund. And that is too bad because I really like the styling and features of the Rockhopper but I guess I could find a Trek or something else that would work for me.

Cyccommute - I appreciate the help you have given.

The first thing I noticed is that the chainrings seem to be almost brushing the frame. Very little clearance.
OK. If I did decide to fix it, what do I do? Seems like it needs a spacer, but what and where?
If it needs a different BB, I sure as heck don't think I should pay for that.

I really don't want to drop this bike back off at the LBS. Right now it is sitting in my basement and I have removed my grips, seat, and bottle cages. I have written a letter to the Specialized Service Dept. I am going to call them when they open and tell them the situation. I will ask that they call the LBS and see if they can come up with a solution. I don't like being put in the position of being a PITA to the LBS. I'm putting the ball in their court. But, at this point I am ready to drop the bike off and demand a refund. And that is too bad because I really like the styling and features of the Rockhopper but I guess I could find a Trek or something else that would work for me.

Cyccommute - I appreciate the help you have given.

It definitely sounds like the bottom bracket is too short. Looking at the specs for the bike, it should have a 118mm Octalink spindle. That a long spindle and should be long enough. You may need a spacer behind the driveside of the bottom bracket to push the spindle out further. Look here to see how to take the crank off (http://www.parktool.com/blog/repair-help/crank-removal-installation-isis-drive-or-octalink) and remove the bottom bracket (http://www.parktool.com/blog/repair-help/cartridge-bearing-type-bottom-bracket-service-bbt). Look here (http://www.parktool.com/blog/repair-help) for a map to everything on your bike. There is some investment in tools needed for the job but how much time have you already spent on fixing this problem?

As for being a PITA, the bike isn't right yet. You have a right to be a pain. This has been going on for far too long. Personally, my bikes never see the inside of a shop once I purchase them but I've invested lots of money in tools and years of experience to get to that level of independence. Now might be a good time for you to start but that's your call.

I rode the bike today. No chainsuck problems. However, in low gear the chain rubs the inside of the derailler cage. I thought, no problem - I'll just adjust the low limit screw. Well, the limit screw was backed out till it was just hanging there and not limiting derailler movement. In other words, all the adjustment has been taken up and the cage still rubs the chain in low gear. In addition to that, when you shift from the small to the middle chainring you have to go way past the middle indent, almost shifting onto the large ring before the chain will engage the middle ring.
I don't know if I should just live with it this way, or pitch a fit and tell them once and for all this bike ain't right and I want my money back. I do know I'm tired of dropping it off at the LBS for them to work on.

When you say low gear, you are talking about the small ring in the front and which one or ones in the back?

Is the deraillieur aligned laterally? If it is very slightly misaligned it can cause a rubbing problem. Sometimes all you have to do is loosen the deraillieur mount bolt and rotate the deraillieur very slightly to eliminate rubbing.