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BBSxx Documentation Master Repository

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    BBSxx Documentation Master Repository

    This document is broken down by topic with each topic having its own post in this thread.
    Click the link to be taken directly to that topic or scroll down to see all topics.


    Picking out partsActual installation

    We recommend you to start with a bench test first, just connect the bare minimum (throttle, display, motor and battery). Just power the display, use the throttle to see if the motor runs fine (you will get error 21h and the motor will shut down eventually but that is normal.)Videos

    How to size your chain once installation is finished

    How to space out a chainring with too much offset
    Last edited by Sebz; 03-17-2022, 05:12 PM.


      Troubleshooting How to bypass display on BBSHD and BBS02 to determine if display is faulty

      An intermittent problem which occurs at all speed/power levels could be a loose connection or short in throttle, brake cables, gearsensor cable or connectors between controller>motor. A problem that only happens at high load is more likely to be something getting hot. Which could be a high resistance connection or short in the power wiring, or an overheating controller, an overheating battery, or a battery that is showing voltage sag beyond Low Voltage Cutoff, or shutting down from pulling a higher discharge rate than the built-in battery management system is built for.



        Replacing a BBSHD clutch ········································· Fixing play in a BBSHD axle

        Controller replacement ·············································· Repacking a sealed bearing with grease, like the sealed bearings in BBSxx


        Replacing BBS02 Controller ········································BBS02 fix for motor shaft noise


          Upgrades and Mods

          Fully greasing a BBSHD (overview video) ~~~~~~~~~~~~~~~~~~~~ How to grease only the secondary gear

          Reworking a cassette for improved chainline


            Frequently asked questions

            Installation related

            How difficult is a mid drive install?
            Not necessarily hard. The hardest part of the install is removing the parts that will be replaced by the motor. Fortunately this part of the job can be done easily and cheaply by any bike shop. Having the shop do this portion of the job is recommended. They do not need to be e-bike mechanics or even an ebike-friendly shop. All they need to know is that you want everything removed from your bottom bracket shell. This is what it should look like.
            Click image for larger version  Name:	CIYpbfm - Imgur.jpg Views:	1 Size:	260.9 KB ID:	77054
            The crank arms and bottom bracket have been removed so there is just an empty hole all the way through, that's what the BBSxx fits into. There is a guide on how to do this in the install section above. After everything is removed from the bottom bracket the install is straightforward. Step one is to measure your bottom bracket width, as seen here. Order your kit to fit this width. Slide the motor into the bottom bracket. You may need to twist it to get it inside if it is a tight fit. Now put the metal plate on, with the teeth facing inward towards the BB so it grips it when tightened. This plate will be fastened to the motor with two bolts, make sure that it is flush with the bolt holes. If not use washers so it is, then bolt it loosely on. Twist the motor into a position so it will be as far away from the ground as possible without touching the downtube. Now tighten those bolts. Then use the lockring tool to put the lockrings on. Now it is time to put the crank arms on, taking care to put the correct arm on each side (they are labelled R and L on the back and correspond to the sides you see when sitting on the bike looking down). Once they are bolted on really tightly just put the pedals on keeping in mind that the left pedal threads are reversed, clockwise unscrews and counterclockwise screws it in. All that is left is minor stuff: where you will put wiring, setting up the various controls, plugging things in etc.

            Tools to complete the job?
            The most important is the lockring tool, because if you do not have the lockring very tight the motor will twist in the BB shell.
            • OPTION 1, wrench type lockring tools. This one works for both inner and outer lockring... Adjustable lockring spanners like this one may also be utilized. There are also tools built for small bike lockrings that should fit this better than the average lockring tool, for example this one, this one or this one. Other lockring tools can work too, for example the Park Tool HCW-5, which seems to work better for removing the old lockring from the BB, but the HCW-5 tends to be too large and slips. There is a wrench that fits the outer lockring as well., another link here (the outer lockring is not as important to get very tight)
            • OPTION 2, special sockets made for the task. These would go into a socket wrench or ideally a torque wrench. They are expensive but if you are having problems tightening and want to stop having to mess with it then it may be worth it. M33 inner lockring socket, and the outer lockring socket, Toolset for both inner and outer
            • OPTION 3, Put the gray inner lockring on finger tight, then put a flat blade screwdriver on one of the notches and just tap it with a hammer in such a way that it tightens it up. You might need to tap for a while and it isn't the most elegant solution but it will work. For the black outer lockring use channel locks covered with a rag to prevent the ring from getting scratched up. Not ideal but it can work in a pinch.
              Other tools:
            • A standard torque wrench with a set of allen head sockets that can be used with torque wrenches (not really necessary, just make sure stuff is well tightened and maybe add some blue loctite to threads)
            • Adjustable wrench, spanners, allen wrenches. Ideally also some blue loctite for the lockring threads.
            • Many chains need a chain tool to open up the chain in order to shorten it and do maintenance. If yours has a "masterlink" then you will need masterlink pliers instead. Since mid drives increase your odds of snapping the chain you should bring a pair of missing links which can easily repair the chain while out on a ride.
            • Tools for matching connectors between battery and motor (check beforehand to see if your supplier will deliver matching connectors). For solderless connecting, this may include butt splices, step-down butt splices, solder sleeves, some heatshrink tubing, and a crimping tool or pliers. See this video to learn how to crimp wires, much easier than soldering.
            • For soldering you need a soldering gun, solder, and heat shrink tubing. If you are installing from the BBSHD to a Luna softpack battery or Wolf these have XT90-S connector so you can use this connector to make everything plug and play. If installing from BBSHD to a hardcase pack it will likely be plug and play as well but using Anderson instead of XT90.
            Good frames to use?
            Any hardtail MTB is usually the standard. Preferably one with a large triangle for mounting a battery inside.
            Got the kit, what is the first step?
            Bench test it! This involves powering up the unit BEFORE you install it on the bike. In this way you can verify it powers on and is operational, and if you run into any further issues once installed you know that has to do with how you installed it rather than anything wrong with the kit itself. You only need a few things connected to bench test the kit: battery power, main wiring harness, speedo sensor, display and throttle. Likely you will see speed sensor error which will immediately go away if you wave the included magnet in front of the sensor. The display will be operational and you will be able to hit the throttle, making the motor spin, with no error (after waving the magnet in front of sensor) For more info on bench testing see this link

            How do I wire up the motor to the battery?
            How to use a BBSHD with a longer axle than intended for my bike?
            Best practices for spacing out a BBSHD

            The manual says specific 35-40 Nm of tightening force for the lockrings (M33), do I need a torque wrench?
            You do not need to, as long as you can get the lockring very tight. You probably will need a good lockring tool though so you can have a good grip on the lockring, otherwise it will slip and you may not be able to tighten it enough.

            There is a gap between my motor and black metal triangle mounting bracket, what do?
            This is what a typical gap may look like.
            Click image for larger version  Name:	Lm56hWd - Imgur.jpg Views:	1 Size:	42.0 KB ID:	77057
            In this picture the black triangle mounting bracket is NOT flush with the motor, there is a 1mm gap. You should add washers until there is no gap. If you do not do this you will have problems keeping the motor in place. The black triangle mounting bracket MUST be flush with the motor. If you buy from Luna we include some spacers you can use. If not or they are not the right width then you should use washers. There should absolutely not be a gap here, if you tighten it without making it flush the bracket will not bind properly with the bottom bracket shell and the motor will move around when under load.

            How to use BBS02 on 73mm BB?
            (This does not apply to BBSHD, which is long enough for 73mm with standard version)
            On a 73mm BB you may not fit the outer lockring on when using a bbs02 or bbs01. You also need to space out the Bafang Unit and the left side mount the extra 5mm using washers, and use longer M6 x 20mm bolts See this picture for a detailed description.
            Use Loctite on the threads of the shaft instead of using the second lockring (which really just acts as a jam nut)
            My BBS appears stuck during install and did not slide all the way through the bottom bracket shell, help?
            It can be a tight fit. Ensure you did not leave any obstructions in the way, then get it the rest of the way in by twisting the motor back and forth while shoving it in. It might take another person to hold the frame while doing this. In the event there are obstructions in there, you would want to file it down then clean the bb well to remove any loose shavings.
            Can you replace the bbs01 controller with a bbs02?
            Yes as long as you reduce max amps to 18A. To do this you need to buy the programming cable. Reprogramming is easier with this custom written Bafang Configuration Software
            Recumbent trikes?
            "I have multiple recumbents. I have a BBS02 on a recumbent tandem trike. I have also tried it on a long wheelbase recumbent, Rans Stratus. There are 2 or 3 things to keep in mind. A mid drive works great on a recumbent but make sure you have room at the bottom bracket for the install. A few have too much frame thickness around the bottom bracket (google the BikeE CT and you'll see what I'm talking about). My Rans is a lightweight long aluminum frame. It was a little too flexy with the BBS02. When you hit the throttle, you could feel the frame flex sideways. A heavier built frame like the steel version would have been fine. Most recumbents would work fine. Sun Seeker is a lower end brand that have several good possible bikes or trikes. A good source of info on electric assist recumbents is the power assist sub forum on"
            Configuring controller PAS with a 5 setting display?
            If you wish to fine tune the 9 PAS levels in the controller for usage with a display that only does 5 levels (ex: DPC 10) adjust levels 1-3-5-7-9. These will apply to 5 level displays.


            What bikes may have chainline issues?
            • Fatbikes with wide chainstays:
            Click image for larger version  Name:	b7fO26C - Imgur.jpg Views:	1 Size:	38.6 KB ID:	77070
            On fatbikes some chainrings that try to move the sprocket further toward the frame (Eclipse) may need spacers to clear chainstay. In the above example the Eclipse might need a chainring spacer to clear it, but this would be preferable as due to how the chainstay pushes the motor out this will have chainline problems and needs a ring that gets it close as possible inbound.
            • Fatbikes that do not have wide chainstays. The wider the bottom bracket (and therefore the BBSHD itself) the more offset the chainline may be.
            • Regular bikes where user accidentally bought a fatbike kit (needs spacers to fit in BB)
            • Small framed bikes, those with small wheels, folding bikes. All have shorter chainstays, meaning the angle from cassette to chainring is more extreme.
            What does one gain with a smaller sprocket?
            With a smaller sprocket you get more torque, but you lose some top speed. The high quality expensive aftermarket 42t chainrings like lekkie and eclipse (not the luna 42t aluminum) also have more offset than stock, which gives you a better chainline so it is less likely to derail.
            How to use on hills?
            Downshift on hills as you would a normal bicycle (or a car with manual transmission). This greatly increase the torque and is one of the key advantages of a mid drive compared to hubmotors. Efficiency stays optimal and stress on the components is minimal. Note: Do not ride this in the wrong gear uphill. High gears are meant for high speeds, low gears are meant for low speeds and high torque. Going uphill in the wrong gear is known as lugging the motor and can damage it. This is as stressful on your drive system as it would be on your body if you were pedaling in the wrong gear.
            Shifting: what is the best way to do it?
            Don't shift under power. Tap the ebrake to cutoff power or let off the throttle for shifting. Some suggest you can backpedal to cut power, then shift. Latest versions also come with a gear sensor plug that can be used with the optional gearsensor, which automatically cuts power when shifting. Using a gearsensor is highly recommended as it is not only easier on the drivetrain, it makes the bike more enjoyable to ride. Also, a quality derailer/shifter that is properly adjusted is much less likely to have shifting problems, and this is where you should start if having shifting problems on the rear.
            How to walk it up a flight of stairs?
            Hold the down arrow on the control pad for display. This will make motor accelerate at walking speeds to easily get you upstairs.
            36v on BBSHD?
            Not possible. Lowest LVC programmable for BBSHD is 38.5 so a 36v nominal pack which gets to around 42v at 100% will still have around 70% charge when LVC cuts out.
            Best practices for commercial use?
            While no sellers warranty for the high rigors of use by pedicabs, rental companies and delivery companies, many companies do use BBSHD in particular for this purpose. The happiest ones take some precautions especially if using all day every day, including regular scheduled maintenance/inspection of the internals taking time to use fresh mobil28 grease if needed, keeping derailer adjusted, keeping chain lubed, adding additional waterproofing around the gaskets on the motor, using dielectric grease on all electrical connections, keeping battery from getting rained on and using additional impact protection in where it is to be placed, and using the program cable to configure the system to operate at a lower amperage and/or other technical optimization such as aftermarket chainrings to balance the output more towards torque rather than top speed.

            And ideally having spare parts for the controller, display, and clutch since waiting for a shipment to get some small part for something critical to running the company can cost money especially if it happens to be out of stock. If using on a rental, users should be instructed not to lug the motor in the wrong gear as this is very hard on the drivetrain. The main practices we would recommend are also described in more detail on this document.
            Typical range?
            Let's say we are looking at a BBSHD mid-drive kit with hot rod settings. That is going to use about 30wh/mi, on average if you are hammering it full throttle the whole way. Now let's say you have a 52v 13.5AH GA shark pack. This is the de facto standard battery pack for most builds. It has about 700 WH. So that's going to do about 23.3 miles at full throttle, throttle only no pedal assist. With a medium level of pedal assist and a bit slower speed, you might have double that range. If you dial down the current limit in the configuration you can also highly increase this setting. If you use BBS02 that's more like 26wh/mi since is has a bit less max current so you can adjust the calculations accordingly.

            If you are asking about Luna prebuilt BBSHD bikes they have an optional 750 W street legal programming setting, with that same shark pack you would be getting 30 miles at full throttle only, again doubling that if you are using a reasonable amount of pedal assist. All BBSHD and BBS02 motors are fully programmable for any level output you want if you wish to further increase your range.

            If you are using a 12ah Wolf that would be about 10% reduction of that base range stat, and if you are using ludicrous controller that would be a significant drop in reduction as it is much higher power level and the more power you use the faster it will run out.
            Last edited by paxtana; 03-02-2021, 02:51 AM.


              MaintenanceGenerally speaking, BBSxx motors themselves do not need much maintenance and most maintenance is external from the motor, for example chain, sprockets, derailer and so on. There are exceptions, for example if you are running it 24/7 or you notice a lot of noise, or have submerged the motor to the extent that the grease may have gotten water in it. This last point is more relevant to BBS02/01 rather than BBSHD, as BBSHD has a sealed secondary reduction gear whereas the earlier models simply have a plastic cover on it.

              In any case, you may want to consider opening it up and greasing the internals after the first year or two depending on usage. After this point, and taking into account using a high quality grease like Mobil28, you should be fine for a long time, though you could do another rebuild/repack later on if you so choose or if the internals are sounding a little louder than usual.