Chain suck problem.

[Ian222]

Hi, ok so new to the seen and bought a haibike hardseven 5 about 6 months ago. All good and have done a few mods riding about on costal paths etc then I started hitting the trails and the common problem arises. So has anyone actually fixed it? I seem to be the only one in my group with this problem as they have cubes and treks and the only difference I can see is their derailleurs have a clutch and mine doesn’t. I have fitted a chain guide to the lower part of the chain but after going round Bedgebury park it keeps happening. So can anyone shed any light on this. Thanks

 

[Coolcmsc]

Why do YOU think you have chain suck? I realise you’re asking the forum btw , so to explain why I‘m asking:—

a) your right there at the time and having the well known phrase ‘chain suck’ as the only clue, which covers a multitude of causes, means it’s hard to decide which cause applies to your bike. It is helpful that other riders in your group are OK.

b) you seem to think it’s the derailleur for some reason, not the chain, and it would help to know your reasoning.

The chain is more often the cause of chain suck.

The chain can cause the type of chain suck that pulls the derailleur forward and up.

And the chain can cause the type of suck that makes the chain stay ‘attached’ to the teeth on the front chain ring at the bottom, instead of letting go to travel on towards the derailleur which sometimes drags the chain up against the bottom bracket area damaging that (not always) and at the same time pulling a fault-free derailleur up and forward giving the impression the derailleur is somehow at fault when it isn’t.

Causes of chain suck in the chain are generally different to causes in the derailleur, or the cassette or the front chain ring or a front chain guide (or similar) if fitted.

 

[Ian222]

New to all this so bare with.
I use the term chain suck as it seems to be the wording used when trying to find a solution. The chain gets pulled up into the front cassette on rough ground or jumps where the chain goes slack. Maybe I need to look to see if the cassette is dirty with grease etc to see if it’s hanging on to the chain instead of letting it go.

 

[steve_sordy]

The only time I have suffered from chain suck was when the ring was worn. The teeth become like hooks that hang onto the chain instead of letting it go to head towards the back of the back.

I had a link to an excellent article on chainsuck by Ibis, but it no longer works! This is the next best thing I could find. Don't be put off by the triple on the front that he uses to illustrate his video, he covers the major points.

 

[Ian222]

Yes I saw that video. My bike is only 6 months old, maybe 650 miles. Would I have worn the cassette that much?

 

[Coolcmsc]

The only time I have suffered from chain suck was when the ring was worn. The teeth become like hooks that hang onto the chain instead of letting it go to head towards the back of the back.

I had a link to an excellent article on chainsuck by Ibis, but it no longer works! This is the next best thing I could find. Don't be put off by the triple on the front that he uses to illustrate his video, he covers the major points.

Helpful vid. Skimmed it a bit, but I don't think ‘chain line’ was mentioned.
Although rare, the worst chain suck I ever had was on a the Alu Pace 303 back in the day. The frame was a brilliant HT, but it’s one recognised problem was they had mucked up the margins for chain line in the frame. With some group-sets, it was impossible to avoid once the chain got a bit muddy leading to drive side chain stay errosion.
Assuming new correctly lubricated components, the commonest cause of chain-line causing chain suck is to the best of my knowledge:-
a) over ambitious front chain ring choice with 2 or 3 rings - either too few teeth on the little one or too many on the big one.
b) poorly fitted rear derailleur
The most common damage causing of chain-line issues is a slightly bent mech hanger or derailleur.

 

[steve_sordy]

Yes I saw that video. My bike is only 6 months old, maybe 650 miles. Would I have worn the cassette that much?

I didn't mention the cassette, I mentioned chain ring (front). But I agree that at 650 miles I would not expect chain or ring wear to be the cause of the problem. Although I have seen many reports on where the chain wore out before 650 miles. Have you actually checked the chain length for signs of wear? Once the chain is worn it starts to wear the gears it comes into contact with; the more worn the chain the faster it wears the gear teeth.

 

[Ian222]

Sorry yes I meant chainring. No not checked the wear yet but will get a tool and check it

 

[RustyIron]

Sorry yes I meant chainring. No not checked the wear yet but will get a tool and check it

Chain suck is when the chainring is worn sufficiently that the teeth are not pulling evenly on each individual link of the chain. All the pulling is on the forward-most link, rather than being distributed around the entire contact arc. The friction of on that single link prevents it from sliding off the tooth, and that link "follows" the sprocket around instead of releasing.

Most often you'll experience chain suck when installing a new chain on an excessively worn chainring. You didn't mention swapping out parts, so we'll rule that out. I'd start by measuring chain elongation. If it's worn a lot, there's a good chance the rest of your drivetrain is worn to some degree.

 

[Ian222]

Ok thanks

 

[steve_sordy]

Sorry yes I meant chainring. No not checked the wear yet but will get a tool and check it

If you have a magic link on the chain then just remove the chain and measure it with a metal tape measure. It is much more accurate than using any sort of gauge over 6 inches or so.

Stretch out the chain on a flat surface, I use the kitchen worktop with a newspaper under the chain. Measure over 100 half-inch links from pin to pin. A new chain would measure 50". A worn out chain will measure 50-3/8" ie 50.375 ie 1.0075 ie 0.75% longer. On a standard tape measure marked in 1/16" you will easily be able to estimate down to 1/32" (0.06%), which is more than accurate enough..

If you are not blessed with the Imperial measurement system and must use mm. Then tough, you are going to have to do some sums. Do your best! One half-inch chain link measures exactly 12.7mm.

 

[Ian222]

UPDATE

so after giving it to be checked out by a friend he can’t see anything wrong with it. I now think it’s the chain coming off the top part of the chainring and not sucking up from the bottom. So looking into a top chain guide to try and stop it.

 

[Coolcmsc]

UPDATE

so after giving it to be checked out by a friend he can’t see anything wrong with it. I now think it’s the chain coming off the top part of the chainring and not sucking up from the bottom. So looking into a top chain guide to try and stop it.

That should help However, it leaves the cause unanswered and in the long term, it would be good to stop the tendency for it to drop off the chain ring.
There‘s another list of reasons the chain falls off the top of a chain ring…..

 

[Ian222]

Yeah I would like to get the bottom of it but I just can’t see why it’s happening. It’s fine if I don’t ride on rough terrain.

 

[Mikerb]

Strange............the pics I see of your model bike have a KMC chainring with a continuous chain guard (ie an outer ring bolted to the chainring). Is yours an open chainring?? Has the outer guard been removed/has the chainring been changed?

Your bike uses the Alivio 9 speed 11/36 derailleur and a Shimano 9 speed chain. Shimano chains are directional. Perhaps worth checking it is on the correct way around!! You have had the chain get stuck in the chainring a few times now by the sound of it so it is quite likely the chain is now damaged. Again worth checking...........or just renew the chain. Your bike is not really designed for really rough terrain and as you already pointed out the Alivio does not have a clutch so if you are descending on rougher trails I personally would avoid being in the highest ( smallest cog) gear since this is when the chain will be most slack.

 

[Ian222]

Yes correct it has the chain guard on the chainring still intact. Kmc writing is in the outside so I think that’s the right way from research. Yeah I think maybe the bike is just not up to the rough stuff.

 

[Ian222]

Ok so chain guide has come but it won’t fit round the seat tube as it’s too small. Maybe it’s time to give up and admit it’s not for trails. It’s absolutely fine and no chain issues for getting out and going over semi rough stuff but it won’t handle anything more than that. Bit gutted really but it wasn’t bought for trails anyway it’s something I have tried and enjoy so a better spec’d bike is the way.

 

[Ian222]

This would work a treat if the bracket fitted around the tube

 

[Beekeeper]

I have the old Bosch small chainring and got terrible chain suck when I put a new chain on. Fortunately I flipped the chain ring over to the other side and problem was solved.

 

[RustyIron]

I use the term chain suck as it seems to be the wording used when trying to find a solution.

No, that's not how solving problems works. You can't just go making shit up.
You should take the bike to a shop, and they can diagnose if there is indeed a problem with the bike.

 

[RustyIron]

so after giving it to be checked out by a friend he can’t see anything wrong with it.

Get smarter friends.

 

[Ian222]

Ignored

 

[Mikerb]

This would work a treat if the bracket fitted around the tube View attachment 74486 View attachment 74487

2 things from your photo. The spec I read online said the correct chain was a shimano 9 speed whereas you have KMC chain fitted. KMC chains are non directional so that is not the problem but given the chain is not what the spec I read said it should be has it been changed...and if so, is it the correct KMC chain...ie 9 speed?
Secondly, the outer ring on the chain ring does the job of a chain guide and is in the way of fitting any other chainguard device, so even if the one you bought fitted the seat post it would do absolutely nothing. The curve on the bottom of the chain guide needs to emulate the radius of the chainring so you can see how much further towards the front of the bike and how much lower it would need to be, to achieve its function.
I know you said you are now after a better spec bike but to get the most out of the bike you have I would suggest you buy a new chain. That way you can get the recommended Shimano chain, ensure the chain is the correct length, and ensure the chain is undamaged. Other than that, as I said earlier, if you on a rough trail keep the chain in the middle of the cassette, not on the smallest cogs.

 

[Ian222]

Ok thanks man. According to the haibike site it stats that it is a kmc e9s chain. I can’t see how long it should be so hard to know that.

 

[Coolcmsc]

So… getting nearer to desperate moves (or paying a good lbs to tell you if it can be fixed).
Consequently, here are some things I’d do before abandoning riding the good stuff on this bike.
a) are you certain the chain is the correct length - reading through the thread again, a few things have been changed, including the chain itself.
b) if you can afford to buy another chain if the following goes wrong, what about shortening the chain by a few links, one link at a time, riding the rough stuff you’d like to ride between each removal? I guess you know you’ll need a quick link, a way of opening and closing that and a chain-breaker tool.
Thanks for hanging in here!

 

[kla456]

Yes I saw that video. My bike is only 6 months old, maybe 650 miles. Would I have worn the cassette that much?

My bike (also German) was bought last year during the period of Covid.
I had a similar chainring problem. I took the number stamped on the chainring and wrote to the part manufacturer. Turns out they don't make a chainring for SH12! I wrote to the bike seller and they wrote to the manufacturer. Bike manufacturer replied with an apology explaining about supply issues during the lockdown. They mailed me the correct part and paid for LBS to do the work.
I don't blame the bike manufacturer who had to keep working and they owned up when presented with firm evidence. No names, no pack drill.

 

[Ian222]

Ok so I have no idea how long the chain is meant to be. How would I find that out? Ring haibike I suppose? It’s not been changed that is the correct chain according to haibike and other sites. They did try to remove a link or 2 but apparently it put too much pressure on the derailleur.

 

[Ian222]

Emailed haibike to ask about length.
Personally I think that the ground I am going over is so rough it’s no wonder it’s coming off. As it’s coming off in the higher gears that’s when the chain is most slack. I will await the answer

 

[Jackware]

I doubt Haibike will reply with anything useful.

Simply search for how to get the chain length correct when fitting, all chain manufacturers will have the info on their websites and YouTube will have plenty of guides.

Don't waste your time looking for obscure faults and cures without checking the basics first.

 

[Ian222]

Ok will try that. Thanks