Announcement

Collapse
No announcement yet.

Chain coming off (for the millionth time probably)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Chain coming off (for the millionth time probably)

    Hello,

    New here but have been searching around for answers but not really finding anything so here goes.

    How often would you expect a chain to come off on a mid motor bike?

    My wife rides about 15-20miles every day on her ebike. Her first ebike was fine for about 8 months but after that we kept getting problems with chain slipping even after repacing chain, cassette and chainring as necessary. Eventually the motor failed after 15 months. This was replaced under warranty along with complete new drive train (chain, cassette, chainring, cable and derailluer) but the chain still came off on a regular basis. So that bike is up for sale :-(

    Two weeks ago we bought a brand new ebike for her with a Bosch 4th generation motor. The chain still comes off the front chainring every second or third day of use. Usually it is underload going up a hill but it does come off on the flat too. It comes off when gears are not being changed. It's 9 speed with a single chainring at the front. It's been back to the shop but they say nothing wrong with it and that chains can come off sometimes. I've even been told it must be her riding technique.

    Bikes are only used on the road - no off roading etc.

    So my questions are:

    How often would you expect a chain to come off on a £2.5k ebike?
    Is it worth getting and fitting a chain guide for the chainring? If so what would you recommend?

    Any help or advice appreciated.


    #2
    I've had bikes that had chains come off often - I've always been able to cure that and never have another chain drop after a fix

    First question - is the chain ring a narrow-wide (i.e. the teeth alternate between narrow and wide to match the chain)? That's solved the problem on more than one for me, the narrow only are much more prone to dropping chains

    I've also put guides and guards on other bikes that have cured it but most of the time just going narrow-wide has solved it for me

    Comment


    • huffnpuff
      huffnpuff
      Newbie
      huffnpuff commented
      Editing a comment
      The guy that converted my bike left the front derailleur on as a chain guide, works like a treat. Of course that wouldn't work on OP's bike, it never had one. These proprietary integrated BB bikes are new basically and have issues. I wouldn't want one myself after reading the reviews.
      huffnpuff
      Newbie
      Last edited by huffnpuff; 10-30-2021, 02:10 PM.

    #3
    OP, what's your chainline look like? Agree with AZ that narrow/wide front chainring is often a good fix, but it would be nice to know what your chainline looks like in all the rear cogs. I mountain bike in rough terrain with a narrow/wide front Luna Eclipse 42T chainring. I've run 9-speed 11-50 and 11-34 in the back, but the chain has still not come off the front chainring even running clutched and non-clutched rear derailleurs. With the Luna chainring my chain lies right, dead in line with the middle of the cassette, which is optimum. For you to have this much trouble riding on pavement, something is wrong for sure.

    Comment


      #4
      I use a roller at the top to keep the chain from lifting up out of engagement due to cross chaining. But I don't run a narrow/wide chain ring. I see it as either or. If the chain gets 1 tooth off in the narrow/wide it will jam up the roller guide due to sitting higher in the chain ring. I like the looks and wear of the Surly stainless steel rings, and run a flat ring on an adapter. The roller works for me.
      The other option would be a narrow/wide with the proper offset. In a pinch a front derailer can be used as a chain guide. No cable or shifter needed.

      You may consider making a narrower casette. Powerful mid drives usually don't need all the gears. This is another way to improve the chainline.
      Retrorockit
      Giga Member
      Last edited by Retrorockit; 09-06-2021, 10:56 AM.

      Comment


        #5
        That doesn't seem right for a store bought E bike, especially something with a Bosch drive. They don't just sell those to anyone and they don't just bolt onto any old bike.

        Have you had it happen to you when you ride her bike? I'm not sure what she could be doing but trying to eliminate as many variables as possible. Only reason I go there first is she had the same issue with another bike. Do you still have the old bike? What was it? Another Bosch?

        Comment


          #6
          Thanks for all the quick replies. Taking the points in order:

          Chainring is not narrow/wide - just a plain chainring. I'll have a look into it but since the bike is new and not cheap I would expect the manufacturer to fit such a thing. However, as we are on her second bike in 18 months I am looking for a fix even if it means modifying the bike.

          I will need to check the chainline in the morning and come back to you on that. I'm assuming as the bike is new it should be straight on the middle - it is a 9-36T 9 speed on the back with a 38T front chainring. There is no clutch on the derailluer.

          With regards fitting a narrower cassette I don't really want to modify the bike too much - it is brand new. I was thinking a chain guide is not anything drastic and shouldn't cause any warranty issues.

          The first bike was a Ridgback with a motor from a company called SportDrive. We bought a pair of ebikes at the same time - mine is a Cube with a Bosch motor. We both rode fairly reguarly for the first 6 months of ownership and never had any problems. Unfortunately a bad knee has forced me off mine since then but she got into using hers every day. After he chain came off the first few times I realised it was probably time for a new chain and this resolved things for a while. Then after about 12 months we had nothing but problems despite regularly replacing drive train components. Around this time the motor started making strange (and loud) noises and was replaced under warranty about 3 months ago. The bike shop assured me it was all fine and it was for another month or so and then dropping the chain became a problem again. For that month I put down all previous problems to the dodgy motor. I replaced the chain, (despite chain measuring tool telling me it was not necessary), rear cassette, chainring and derailluer but it still kept dropping chains on a regular basis despite everthing being constantly checked and cleaned. Eventually the chain came of, jammed up and spat her off the bike and she refused to use the bike any more. We still have the old bike - I've just replaced the wholle chainset again with the intention of selling it but I feel slightly guilty about that!

          That was 3 weeks ago and we bought a brand new Bergamont bike with a Bosch motor. My thinking was there had never been any problems with my bike with it's Bosch motor so we should stick to a bike with a Bosch motor. As I say the chain doesn't come off every day but it's often enough to be a pain. I have ridden it myself and the chain has not come off but my bad knee is stopping me put any real effort into it. My guess is she is riding faster and harder than she did at first with the other bike because we were new to ebikes when we bought them last year. Having said that we are in our 50's and I'm sure a £2,500 bike should cope without any issues.

          I'm becoming a bit disillusioned with the whole ebike thing but she enjoys her daily ride and just wishes she could get on with it without having to stop and put the chain back on. It is also at the back of her mind it may jam up again and spit her off again. We put the problems down to the Ridgeback having a make of motor we had never heard of (and it did fail) and so bought a new bike thinking everything would be rosy. The trouble with the chaining coming off only every second or third day of use means the bike shop taking it for a test ride never finds a problem.


          Comment


            #7
            When I was having problems with the chain coming off I'd carry a medium size binder clip clipped to a cable on the handlebars and use it to put the chain back on. I had a technique of clipping the binder over the chain and then bringing the chain back on quick an easy without dirtying up my fingers. Didn't even have to get off the bike. Not a long term fix but until you have your fix it makes it less a pain.

            I have no idea how easy it is to get different rings for the bosch but if a narrow-wide is an option I'd be all over that - they just plain work better and last a *lot* longer and like mentioned on more than one bike that used to drop chains every few days (I ride a lot so not all the time but enough to be more than annoying) but since going to narrow-wides never a drop since. I'd been using the narrow-only to figure out which size for one bike and they are a lot less expensive than the narrow-wides. Funny thing - I was just digging around in my parts for a ring with more teeth and I sure have a lot of rings.

            I have another "store-bought" bike that's a rear hub drive and it would drop them every ride... super pain in the arse and the chain would often get all caught up in the cadence sensor so even more a pain. I cobbled a guide and that worked pretty good at keeping the chain on - that bike even being a stock electric bike had a horrible chain line and that was a big factor. Ideally you want it a little towards the larger rear cogs, not necessarily in the middle but close enough is generally good enough. That guide was sort of kludged and didn't always do the job. I ended up putting chain ring guards on each side of the ring and never had it drop one again after that.

            So take heart, whether narrow-wide rings, guides, guards, rollers or a combination it can almost certainly be fixed so it *never* drops the chain. Don't let your wife blame it on technique, it's just that some bikes are prone to it and need a remedy...

            Comment


              #8
              Thanks again.

              I'll take heart from the fact that it can be fixed. I'll look into both the guides and the narrow-wide chainring.

              I'll start with the bike shop first and see what they can offer...............

              Comment


              • hoggdoc
                hoggdoc commented
                Editing a comment
                After reading through all your comments I think it's something your wife is doing. Possibly not using the gear probably causing high torque loads on the chain. Ask her specifically what she was doing each time the chain comes off, what gear, cruising or starting off, shifting gears etc. this will allow you to zero in on something that she might be doing.

                I know you just bought her a new bike, but maybe think about getting her a bike with a belt drive and internal gearing at the rear. I doubt no matter how whe rides it she won't be kicking the belt off. As a plus you will lose a bunch of maintenance on her bike.

              #9
              A quick look this morning and the chain line appears dead straight when in the middle gear so I guess that is OK.

              Now this could just be my imagination but when looking closely at the front chainring whilst cleaning the chain this morning I would say that it is slightly distorted - only by 1-2mm but maybe that is enough for causing problems. The bike has now covered 300 miles. I will contact the shop when it opens.............

              Comment


              #10
              This whole scenario sounds strange. The only time I've had front chainring drop in all the years I've been riding was on either a poorly set front derailleur...not a problem in OP's case...or on gnarly mountain biking, going downhill, in very rough terrain that was pounding the rear suspension and causing the chain to flail around. To remedy that I used MRP chainring guides and or homemade aluminum setups I built.

              Especially since the OP has found the chainline to be dead-on, I find it odd that riding on pavement on a rigid rear triangle would cause this many issues. A bent front chainring can cause this, but he's had this issue over more than one bike. Even my 2-chainring road bikes ridden on a rough gravel road didn't drop the chain if my derailleur was set properly. I wish we could see some pics of these bikes that have had such a recurring problem with chain drop. I'm not suggesting the OP isn't giving us all the info here, but this consistent front chainring drop across different bikes seems unusual...at least to me.

              Comment


              • hoggdoc
                hoggdoc commented
                Editing a comment
                The only common denominator is the rider, maybe be a tough thing to over come if their communication lines aren't good.

              #11
              Pictures of the Ridgeback. Newly fitted complete chainset ready for selling!

              Comment


                #12
                Now the brand new bike with 300 miles done. We've removed the plastic chainring cover to make it easier to lift the chain back on when it comes off. Now I think the front chainring might be slightly bent but I'm doing that by eye only and may be imagining things. If it is slightly bent I have no idea how - it doesn't look easy to bend. It's booked to go back to the shop next week for them to check it over. As I say it's a brand new shop bought bike and this is the reason I'm here - I wanted other opinions as to how often a chain could drop on average and it seems the answer is nearly never on a properly setup bike. Now I have to assume a bike shop sets it up correctly during a PDI and then it should just be ridden until time for a new chain etc. due to wear and tear.

                Comment


                  #13
                  The only time my bike has dropped the chain ( and it was fairly often at first) was when I would down shift a bunch of gears at once before coming to a stop. Coasting at speed in too low of a gear seems to make this happen. The motor would rev up with no drive tension on the chain and it would come off. I didn't go with the offset n/w rings because they were expensive and didn't come in the 50t size I needed. So it was a chain guide for me.
                  In the lowest, and highest gear with the rear wheel off the ground, turn the pedals and looking down at the top of the chain ring, watch to see if the tooth entering the narrow part of the chain is trying to lift it up.
                  If so , then a narrow/ wide will help. But the chain can't move side ways off of the chain ring unless it first lifts up at the top. That is how a rolller chain guide works.
                  In marginal situations like my known bad chainline w/o n/w frequent lubrication can be the difference between success and failure. I use Squirt which is a dry wax based lube I wipe the chain with a rag, and brush as much old lube off as I can. Then lube the chain. Every other ride works for me. I notice there is no chain guard on the bike. Perhaps that might help feed the chain back into position. I also notice there is no lube on the chain ring teeth.
                  One time the chain kept coming off at night, and I stopped at a convenience store and bought some Power Steering fluid and dumped it on the chain. It made a hell of a mess but it saved me a long walk home. A lesson learned.
                  Retrorockit
                  Giga Member
                  Last edited by Retrorockit; 09-07-2021, 08:44 AM.

                  Comment


                    #14
                    I had one bike that was a real pain dropping the chain on most rides once or even twice - factory bike with no driveline modifications and a rear hub drive so no excess loads... was areal nuisance for sure. The crank had a cadence sensor that pushed the arm on that side way out and the chain line was really bad with the ring lining up with the top gear and the drops would occur generally when shifting to the lowest gears (sometimes it'd come of when not shifting but mostly when shifting) and often enough the chain would get lodged between the cadence sensor pickup and the magnet disk - eventually it was likely going to mess that up and it was a pain to dislodge it.

                    It was really difficult to figure out a guide since the ring was so far from the seatpost in order to have room for the cadence sensor on the crank. I got a typical one and with some creative scrounging for hardware made the post supporting it silly long and that work pretty well... Far less frequently I still got some drops every now and then but the guide made it even more a pain to put the chain back on.

                    There was already and chain guard on the outer side of the ring so I went and got another guard, somewhat oversized and did some creative hardware and mounted it on the inside. At first in the lower gears the chain would crawl up on the guard sometimes and come down on the cadence sensor but eventually I got it all situated properly and never a drop since. It's very simple and clean and doesn't interfere with a thing.


                    The OP is saying he might have a bent in the ring and that alone would *easily* cause drops so I'd deal with that before anything else. If he can get a narrow-wide perfect time to do so... if nothing available in narrow-wide then at least get something that's good...

                    Comment


                      #15
                      Thanks everyone.

                      I'll experiment with looking at the chain on the chainring from the top in the morning. Mainly just to see if I can get any hints to give to the bike shop when it goes in next week.

                      Comment

                    Working...
                    X