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Crank and thumb accelerator slipps

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    Crank and thumb accelerator slipps

    My BBSHD kit was installed Feb 2 2018, 4 months ago. It first noticed the accelerator and then the crank started to "grind" as well when I needed to ride the bike. When I was ride, it feels like I'm jumping/missing a gear. Then I it got worse and I had to walk the bike home, up the mountain, which I wanted in the first place. i looked the picture of the clutch part to buy it, but the tech said the clutch is shot if the crank is bad BUT the accelerator is normal. Mine is NOT normal. I thought it was the clutch but now i don't know. Any thoughts?

    Hi -

    If you use the accelerator (throttle), not the pedals and you 1.) hear a grinding noise and 2.) the chain doesn't move / roll normally, the plastic gear within the BBSHD motor might have failed. Otherwise, if the chain is moving / rolling normally, I would then suspect an issue in / with the rear hub. Both of these scenarios presume the motor makes at least some quiet, whirring noise.

    If I remember correctly, the bike can be difficult at best to pedal (or roll backwards) if the plastic gear fails.

    What brand / model bike do you have?
    BBSHD/BBS02B builds: IGH 1 2 3 4 5 Derailleur 1


      Yeah a few may I ask about your mechanical ability and if you have access to bike tools
      I want to know where to launch from
      Last edited by Robert Larrison; 06-21-2018, 11:28 AM.


        I just noticed Michael's other post:

        I have a problem with my motor. I bought my kit this Feb 2018, order #46308.
        I can’t us the bike at all because the motor slips or hit a gear that can’t go while trying to ride my new bike. As it is now, it is useless. It doesn’t matter if I’m pushing down at the crank or even if I use the thumb accelerator. It grinds badly, slipping or cranking. As I’m trying to ride up the hill, I have to stop and have to push the bike up to get home. I think also the same fault that often makes the chain to jump of the front crank. Either way, both are a problem and I can’t use my bike.
        Is it under warranty? I sure hope so.
        What should I do???
        Michael Dondelinger
        Based on this other post, Michael may have several issues with his bike's setup (as HIGHVOLTAGE pointed out) - chainline misalignment among things ("As I’m trying to ride up the hill, I have to stop and have to push the bike up to get home" presumably in a low, high chain angle gear).

        As Robert asked, how's your mechanical skills? A few pictures of the bike might help, especially one showing the chain line.
        Last edited by ncmired; 06-21-2018, 12:19 PM.
        BBSHD/BBS02B builds: IGH 1 2 3 4 5 Derailleur 1


          Sorta sounds like the chain might be skating


            Just a little follow up on chain line misalignment, which is not an uncommon issue particularly with BBSHD builds because of how much further out from the bike frame the chain ring often ends up.

            Here's our dilemma - on the BBSHD, the (single) chain ring is too far out, forcing the chain to kink or bend severely when using the largest rear cog:
            Click image for larger version  Name:	crosschain.jpg Views:	1 Size:	10.0 KB ID:	67557

            The view from the rear:
            Click image for larger version  Name:	Chainline6.jpg Views:	1 Size:	33.5 KB ID:	67558

            Bending or kinking the chain to this extreme leads to problems, such as the chain skipping or skating (riding or slipping around the outside of the rear cog gear teeth, as opposed to engaging them). Luna's proprietary two piece Eclipse chain ring reduces this misalignment the most (of all of the off the shelf possibilities).

            Chain line misalignment is just one of the possibilities - other issues may be a worn out (stretched) chain, stiff / corroded chain links, bent cog teeth, bent / misaligned derailleur - among things.
            Last edited by ncmired; 06-22-2018, 12:06 PM.
            BBSHD/BBS02B builds: IGH 1 2 3 4 5 Derailleur 1


              You know, I think you all might be right about the chainline. I bought both, the new motor kit and bike from the shop and it’s a Specialized brand bike, but I think the components are just crappy and I didn’t know that. So, I’m looking for better parts, maybe Deore parts with mid level stuff. I’m not a mechanic, but I have the right tools and I have the ability to fix them. I need more learning to know all about components.
              Also, I also think I have too gears in the cassette, which I bought, with 9 gears. With the single Crank from Luna (can I add another front ring?) and with 9 gears I think is should be down to a 6 speed cassette.
              What to you think? I’m already to replace the new derailer. The question is, which brand /model of the derailer and which cassette. I guess I’ll also need to replace the old thumb shifter for 6 speeds at the handlebar.


                Unfortunately, if your bike has a chain line configuration issue, new / more expensive parts won't fix it - well, maybe other than the Eclipse chain ring.

                I would nix the idea of going back to the now very old six-speed pre-indexing specification. In a pinch, you could adjust the rear derailleur to simply not allow access to the biggest, max chain deflection gears, presuming you can get up the hills where you live using one of the mid gears.

                I would also nix the idea of grafting a second chain ring to the BBSHD, as that would likely just compound a chain line issue.

                ... again, the above presumes the chain line is the issue. Can you post a picture similar to the blue framed bicycle picture I posted? Does the bike pedal / accelerator power ok in the higher gears?

                P.S. Kailua-Kona huh. Upwind or downwind of the volcano(s)? I'm sure someone on this forum would be happy to give you a free on-site diagnostic opinion on the bike's issues, providing you pay for the airline ticket ;-) just kidding!
                Last edited by ncmired; 06-22-2018, 12:56 PM.
                BBSHD/BBS02B builds: IGH 1 2 3 4 5 Derailleur 1


                  Dondelinger check the forum for IGH internal gear hub its what's best for the chain line issues that the bb's create
                  definitely get one with disc brake

                  additionally check the posts about riding in hilly areas basically ditch that manhole cover bafang sent and get a mighti mini or a small lekkie bling ring

                  im doing delivery in San Francisco on a very heavy cycle truck before that ipedicabed in Waikiki until Fasi ended it


                    Really? Are you saying I'm screwed? Even with the crappy components I already have? Not changing from 9 down to 6 speeds? A completely different bike? I bought the wrong bike?
                    For sure, I can't ride my bike up the mountain. I need the largest gear to get me home.
                    Damn, this is upsetting.
                    Attached Files


                      Sorry about the picture of my TV remote. I was testing for a pic to see if I could send something to the forum. I never sent a pic to the world before.
                      Attached Files
                      Last edited by dondelinger; 06-22-2018, 03:04 PM.


                        Your not screwed get a smaller front ring and that helps a lot
                        I just installed the igh I've been using the derrailler till then and riding lots of hard miles

                        I don't know what bike frame you have but disc brakes are a great choice for a electric bike for 2 reasons first of you can go a lot faster secondly go down those hills that you now can zip up

                        I was using a bakfiets with just a drum rear and a caliper front break going down step hills I was using one foot as a brake


                          Looking at your pictures you do have the common chain line issue
                          As you see your mid to high gear is no problem if you use a smaller front gear it will be easier

                          I noticed no disc brake mounts this will solve the problem I put one on that tank and it worked perfectly

                          If your broke put that bafang front gear ring on a stick and sell it to a tourist as a leiomano


                            OK, I'll take it a look at the eclipse ring. I can't imagine what is any differentce but you probably know. You say the ring makes the alignment better?


                              Originally posted by dondelinger View Post
                              Really? Are you saying I'm screwed?
                              Hey - no, you're not screwed, by any means! It's just that the kind of parts / updates you were thinking of wouldn't have fixed this issue - and most likely it is fixable / can be made to work much better.

                              The pictures you provided tell most of the story. We need to know a little more about the motor install. You wrote in your first post, "My BBSHD kit was installed Feb 2 2018, 4 months ago" - by whom, a bike shop?

                              We could really use one more picture when you get a moment. Here's an edited view of one of your pictures - note the yellow arrow areas:
                              Click image for larger version  Name:	image_13045.jpg Views:	1 Size:	46.9 KB ID:	67601

                              What we need to know is if there is a silver spacer between the motor big gear housing and the bike frame "bottom bracket" and if the motor big gear housing is up against the horizontal or "chain" tube. We also need to know how close the standard Bafang chain ring you have is coming to the same chain tube. If you flip the bike upside down and take a picture of the bottom of the motor you can answer what we need to know in one picture. What we're trying to determine is that the motor is tucked as close to the bike frame as it can go, which affects the chain line, and if you have clearance for the best chain line issue chain ring available, the 42 tooth Luna Eclipse (which would also lower the bike's gearing a little from the stock 46 tooth chain ring you have now).

                              Fitting the Bafang BBSHD correctly or "best" can take a little fiddling. If the eclipse chain ring will fit that would be great, but we have to check that there's room first. The rear freewheel gearing could also possibly be improved for your hills, but let's not go there yet.
                              Last edited by ncmired; 06-22-2018, 05:15 PM.
                              BBSHD/BBS02B builds: IGH 1 2 3 4 5 Derailleur 1