CHAIN SUCK CURED BY FILING

georgehenry

Esteemed Pedelecer
Nov 7, 2015
866
824
Surrey
I ride a Haibike sDuro HardSeven SL 2015 Yamaha and have covered 1600 miles since March 2015. I commute about 23 miles return trip to work with 13 or so of them off road. I have had remarkably few issues with my bike however with the advent of wetter weather I have suddenly become afflicted by the dreadful Chain Suck phenomenon. This is where your pedalling comes to an abrupt jamming halt, usually while you are pushing hard on the pedals climbing a hill! Just where you want to stop! I am no mechanic and did not know what causes it. I asked a friend who said it happened when the chain does not release from the front sprocket where the teeth have become slightly hooked with wear and the chain gets pulled around and jams. He suggested changing the transmission with a new front sprocket, cassette and chain.

I was about to do this but had wanted to keep my old transmission on the bike during winter and put a new one on in the spring being a bit of a skin flint. I googled chain suck and found chain suck in a nutshell. There I found a way of getting rid of chain suck by filing hooked teeth to allow the chain to release normally. Well I thought if I am going to have to replace it anyway I might as well give it a go. I turned my bike upside down, lifted the chain of the front sprocket and had a look. Sure enough I found a few hooked teeth. I carefully filed every tooth just enough to remove the hooking. I then took it out for a muddy ride and to my surprise I had cured my chain suck! There was no chain slippage and it all worked as it should do. Now I am sure I will need a new transmission in the not too distant future but I have to say it has completely cured the problem. I owned a good file and the whole operation only took a few minutes. The teeth on my sprocket were not in terrible condition and a new sprocket might be a better approach if your sprocket is obviously knackered!

I have now covered 75 miles on the road with chain and sprockets working perfectly. Next week I will be doing another 92 miles (depending on weather) with 52 of those miles off road and will report how I get on.

I know there are different philosophies to chain and sprocket wear with some recommending changing the chain as soon as it reaches the wear limit and others just saying not to change the chain and just to use it until the chain is completely knackered and then change the whole transmission with new cassette, chain and front sprocket. I did try the changing the chain at wear limit approach but now find the wear it out approach better for me.

Whatever approach you take you need to keep the chain and sprockets clean and lubricated.

I am still new to the site and did post this into another forum posting and also tried sending a message from which I got very useful information from Fordulike about chain care and a comment from EddiePJ about how the small front sprocket on the newer Bosch drive can be badly effected by chain suck but was cured for him by engaging the clutch in the rear mech

For those of you riding through the winter months and venturing off road I thought it might be a good thing to have a wider discussion about.
 
Last edited:
  • Like
Reactions: Emo Rider

flecc

Member
Oct 25, 2006
46,167
22,882
I ride a Haibike sDuro HardSeven SL 2015 Yamaha and have covered 1600 miles since March 2015. I commute about 23 miles return trip to work with 13 or so of them off road. I have had remarkably few issues with my bike however with the advent of wetter weather I have suddenly become afflicted by the dreadful Chain Suck phenomenon. This is where your pedalling comes to an abrupt jamming halt, usually while you are pushing hard on the pedals climbing a hill! Just where you want to stop! I am no mechanic and did not know what causes it. I asked a friend who said it happened when the chain does not release from the front sprocket where the teeth have become slightly hooked with wear and the chain gets pulled around and jams. He suggested changing the transmission with a new front sprocket, cassette and chain. I was about to do this but had wanted to keep my old transmission on the bike during winter and put a new one on in the spring being a bit of a skin flint. I googled chain suck and found chain suck in a nutshell. There I found a way of getting rid of chain suck by filing hooked teeth to allow the chain to release normally. Well I thought if I am going to have to replace it anyway I might as well give it a go. I turned my bike upside down, lifted the chain of the front sprocket and had a look. Sure enough I found a few hooked teeth. I carefully filed every tooth just enough to remove the hooking. I then took it out for a muddy ride and to my surprise I had cured my chain suck! There was no chain slippage and it all worked as it should do. Now I am sure I will need a new transmission in the not too distant future but I have to say it has completely cured the problem. I owned a good file and the whole operation only took a few minutes. The teeth on my sprocket were not in terrible condition and a new sprocket might be a better approach if your sprocket is obviously knackered!

I have now covered 75 miles on the road with chain and sprockets working perfectly. Next week I will be doing another 92 miles (depending on weather) with 52 of those miles off road and will report how I get on.

I know there are different philosophies to chain and sprocket wear with some recommending changing the chain as soon as it reaches the wear limit and others just saying not to change the chain and just to use it until the chain is completely knackered and then change the whole transmission with new cassette, chain and front sprocket. I did try the changing the chain at wear limit approach but now find the wear it out approach better for me.

Whatever approach you take you need to keep the chain and sprockets clean and lubricated.

I am still new to the site and did post this into another forum posting and also tried sending a message from which I got very useful information from Fordulike about chain care and a comment from EddiePJ about how the small front sprocket on the newer Bosch drive can be badly effected by chain suck but was cured for him by engaging the clutch in the rear mech

For those of you riding through the winter months and venturing off road I thought it might be a good thing to have a wider discussion about.
Yes, that's a guaranteed solution since it is the hooking that causes the problem. The problem is very real on the new Bosch unit with it's small chainwheel, due to the much higher wear rate at that size.
.
 
  • Like
Reactions: Emo Rider

EddiePJ

Esteemed Pedelecer
Jul 7, 2013
4,594
3,978
Crowborough, East Sussex
www.facebook.com
flecc, the Haibike sDuro HardSeven SL uses a Yamaha motor not Bosch motor, and it runs a runs a conventional size chainset.
 

flecc

Member
Oct 25, 2006
46,167
22,882
flecc, the Haibike sDuro HardSeven SL uses a Yamaha motor not Bosch motor, and it runs a runs a conventional size chainset.
Thanks Eddie, I missed that was the case. As it's cropped frequently on the new Bosch units I assumed yet another case.

I'm a bit surprised at the larger chainwheel on the Yamaha suffering it after only 1600 miles.
.
 

craiggor

Esteemed Pedelecer
Jan 9, 2015
498
171
My cheap chain looks nearly ready to be replaced on 1200 miles.I will get a few more miles before I replace. New sprockets still OK.rear hub motor.
 

EddiePJ

Esteemed Pedelecer
Jul 7, 2013
4,594
3,978
Crowborough, East Sussex
www.facebook.com
flecc, I must admit that I was also surprised that one.

georgehenry, just out of interest what is the front chainset material?
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
866
824
Surrey
To be honest I am not sure what material it is. It is the one that was fitted to the new bike, and I have not changed it yet! I looked on the spar parts section of the shop I bought it from but the material the replacement it is made from is not stated.
 

Croxden

Esteemed Pedelecer
Jan 26, 2013
2,067
1,336
North Staffs
It may be foolish to say, but my Bosch has over 7,000 mile on the same chain & sprockets. The small size seems to standing up OK for me.
 

flecc

Member
Oct 25, 2006
46,167
22,882
It may be foolish to say, but my Bosch has over 7,000 mile on the same chain & sprockets. The small size seems to standing up OK for me.
Good to hear. Other things can have an influence on chain suck occurring, for example some derailleur conditions can make chain thrash more likely when changing gear. Then when the chain momentarily goes slack between the chainwheel and rear mechanism as that mechanism bounces, there's no tension on the lower chain run to stop the chain winding round the chainwheel.

Momentary back pedalling and then quickly changing to pedalling can also cause chain snatch and cause chain suck, so even a rider can have an effect.
.
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
866
824
Surrey
I had no issues until the wetter weather arrived. In Surrey we have a lot of sand that after rain can mix in with the dirt to form a substance a bit like grinding paste!

I have an old rim braked Marin (Bobcat trail) mountain bike that still sits in a dusty corner of my garage and never suffered from chain suck however knackered the chain set got and I only changed everything when the chain started slipping.

I wonder if the geometry and design and alignment of how the chain runs on any given bike makes that bike more or less susceptible to the issue. I really did not know what caused it although I assumed it related to a worn out transmission rather than mostly the front sprocket. The revaluation for sceptical old me is that a simple solution obtained from the web was so easy to apply and has so far worked so well. I did not have to take anything off the bike, just whip it upside down, slip the chain off the front sprocket and spend a few minutes gently filing away, slip the chain back on, pop it the right way up and pedal away with the problem so far solved.

It will be interesting to see if it keeps working. Changing a cassette chain and front sprocket does cost a fair bit and a solution that extends the working life cannot be a bad thing though time and muddy off road conditions will put this to the test.

On my Oxygen E-mate city bike I only changed the front sprocket every other time when changing the chain and rear cassette.

I agree with EddiePJ that a relatively large front sprocket should be quite resistant to wearing quickly.

And then we have Croxden managing 7000 miles with no problems on the same chain and sprockets including a small front one! There is no justice in the world. What proportion of those miles is off road Croxden? Probably all of them.

One other thought. Could you just take the front sprocket off and put it back on the other way round, flipped over?
 
Last edited:

Gringo

Esteemed Pedelecer
Jun 18, 2013
1,150
702
Northampton
Save your file.
On my Bosch motor I just turned the sprocket around, now the chain runs on the unused side of the teeth.:cool:
 

Martin@e-bikeshop

Esteemed Pedelecer
To be honest I am not sure what material it is. It is the one that was fitted to the new bike, and I have not changed it yet! I looked on the spar parts section of the shop I bought it from but the material the replacement it is made from is not stated.
Hi Henry,
Its lightweight alloy. Maybe go steel on replacement :)
 
  • Like
Reactions: EddiePJ and robdon

georgehenry

Esteemed Pedelecer
Nov 7, 2015
866
824
Surrey
The lightweight alloy might explain why I could file it so easily but would account for susceptibility to wear although the sandy conditions in Surrey and a high proportion of off road miles has taught me that I can wear out sprockets and chains on any of my mountain bikes pretty fast.
 

Emo Rider

Esteemed Pedelecer
Jan 10, 2014
659
413
Worn gear teeth are usually a sign that one is not lubricating their chain properly or has cycled too long with a worn out chain. The roller bearing surface that seats in the gear must be free and able to rotate on the link's axle pin. Badly rusted chains are obvious causes of gear wear. However, I have seen many chains coated with thick black oily goop that is dutifully lubricated thinking it will protect the drive train. When in fact the roller bearings have long since seized because the goop is preventing the oil from penatrating. Even as dutifully as I cleaned and lubricated my chain, at 7,000 miles I have had to rotate my 9 tooth drive gear and my steel chainset is starting to show wear. I am on my second chain, BTW, replaced at around 4,500 miles.
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
866
824
Surrey
Yes Emo I think you are right about keeping chain and sprockets clean and suitably lubricated. I have actually been quite (by my standards) diligent with the sduro. As part of cleaning the bike I do use a degreaser and chain cleaning device before lubricating the chain. I use the bike just as a ride to work commuting tool and don't clean the chain and sprockets after each journey too and from work but generally at the end of my working week that is usually a four day week of 92 miles total and 52 miles off road though sometimes longer. Obviously if I get the bike really dirty due to the conditions I will give it a clean but usually hope to complete my working week before a thorough clean just adding a bit more lubricant to the chain or a quick clean degrease and lubricate as required.

Fordulike recommended " I would say that definitely keeping the drivetrain clean and using a good dry lube would help too.

I personally think wet lubricants make the chain slightly stickier and increase chain suck, but I'm not an expert.

I use Finish Line Dry Bike Lubricant on my BBS02 and the drivetrain is holding up well at over 1500 miles.

Hope you have many more miles on your bike".

My somewhat lazy strategy is not to change the chain often but keep the chain and sprockets together until they stop working. However I do try to keep them as clean and lubricated as possible. I think I will take Martin's advise to put a steel replacement front sprocket on when I do change cassette and chain in due course. I may try the dry lubricant recommended by Fordulike to see if this makes a difference. Continuing to ride through the more challenging winter conditions with a chunk of off road miles is going to wear things out. I would just prefer to change everything in the spring if possible. I expect to replace my drive train once a year but will keep riding while it keeps working, but obviously change it all if needed. Basically I try to make it last as long as possible.

The Yamaha is one of the more powerful legal crank drive systems with a nice chunk of torque, and I am a big but fit guy so the combination probably gives the drive train a testing time.

My Oxygen Emate city hub drive bike seems to put the chain and sprockets under much less strain.
 
  • Like
Reactions: Emo Rider

georgehenry

Esteemed Pedelecer
Nov 7, 2015
866
824
Surrey
Hi all, time to report back. I have completed my four days of work, riding every day and completing another 92 miles with 52 of those off road. There has been quite a bit of rain leading to challenging conditions off road and I have adapted my route to miss a particularly churned up single track hill that is fun in the summer but has little to recommend it now that horses have turned it into a quagmire. Fortunately there is an alternative that bypasses this section that only adds about a quarter of a mile.

The chain suck is still cured but I now have the occasional recurrence of a previous problem. Basically getting to work riding 13 mainly off road miles gets the transmission quite dirty. Going home fast on my hilly B road as fast as I can, is fine in every gear except top gear (9)(The one you most need to work properly!).

Under the combined load of me pushing hard on the pedals and the motor adding power everything is fine until top gear where the chain/motor seem to hiccup a bit like the chain slipping for a moment causing the motor to interrupt the power delivery. If I back of the power of my pedalling and then gently increase back to more powerful pedalling all can be well again but every now and again the problem will recur needing me to back off my pedalling momentarily before gently increasing the power of my pedalling. When I give the chain and sprockets a good clean and fresh lubrication the problem can disappear, but will recur when everything gets dirty (the natural state of a mountain bike in winter) but not always. Clearing the smallest rear cassette sprocket and the front sprocket helps to alleviate the problem.

I did have this problem when the bike was quite new and the cause on that occasion was a stiff link in the chain. I wonder why it is only top gear that seems susceptible to this problem. The first 75 miles I covered after filing the front sprocket were on the road starting with a clean lubricated transmission with no problems occurring.

It is an annoying problem because it effects me when I am travelling at my fastest cruising speed, and not wanting to go slower. So although I have cured my chain suck by carefully filing the front sprocket I now have another transmission based issue that might mean I have to bite the bullet and change everything anyway. Any ideas let me know. I guess the most likely cause is some minor damage to the smallest rear cassette chain ring that is exacerbated when things get dirty.

Maybe the power and torque of this new generation of crank pedal assist bikes will require a more robust transmission than a traditional bicycle one? Is anyone else having problems like this? Maybe a belt drive and hub gears suitable for mountain bikes would be a solution. The carbon belt drive and the Shimano Alfine 11-speed fitted to the Kalkhoff Intergrale with suitable gearing could be the basis of a longer lasting solution to riding off road in wet/muddy conditions. Perhaps I should just accept that doing the miles I am and continuing to do so through the winter will need more frequent changes of transmission components than I have been previously used to.

In a review of my bike another owner also found it easy to damage the rear cassette when the gears were not perfectly indexed. To quote from his review:

"I decided to replace the rear dérailleur. Know the Deore unit is meant to be good, lots of people have told me that is the case but it has a medium cage length which is not required for a single front chain ring. I ordered a Shimano XT short cage dérailleur (which sadly I had to get from Germany!) and once set up the gear change performance is absolutely incredible. I now keep a spare cassette however just in case and make sure to make regular checks to the gear indexing. If you can't do this, I strongly recommend learning how. It's not hard but takes some patience and practice and will save you a lot of time and money in the long run."

So perhaps it is time to try and understand the dark art of gear indexing combined with a shimano XT short cage derailleur as well as a chain cassette and front sprocket.
 

flecc

Member
Oct 25, 2006
46,167
22,882
I think it's the greater wear rate on the small top gear sprocket that makes it the most likely to give this sort of trouble, since it can be more dependent on everything being just right. Throwing some mud and grit into the mix can tip it into criticality.

There's a similar situation with the Panasonic crank units. The old early one used a 14 tooth motor drive sprocket onto the chain and that never gave trouble. The new unit using a tiny 9 tooth sprocket has given lots of trouble when everything hasn't been just right, but swapping that out to an 11 tooth improves things for owners.

The smaller the sprockets the more fussy they seem to be.
.
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
866
824
Surrey
Thanks flecc, that makes sense. My current rear cassette is a 11-34 and there is an option for a 12-36, so one extra tooth on the smallest ring, not much more but it might help when I change it, although I bought two spar 11-34 when they were £10. I could also try to get a front sprocket with an extra tooth to compensate for that extra tooth and a bit more as the bike feels as if it could cruise a little quicker than it does at the moment, although you still want nice low gears for steep off road hills. Everything is a compromise. Next week my commuting will be mostly on the road and if I start with a clean drive train I hope not to encounter the problem although these type of problems tend to get worse rather than better. I will see how I get on.
 

Advertisers