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Trek Shift2 Comfort Hybird Conversion with BBS02 Mid drive

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    Trek Shift2 Comfort Hybird Conversion with BBS02 Mid drive

    OK, here is as promised, a Noob to E-bikes doing a conversion build to my bride's Trek Shift2.

    She swapped from a Giant 3sp Cruiser a couple of years ago, to get more/better gearing and a lighter frame ride. Lately she has been having foot problems (stress fracture) which have limited riding. We tried some E-bikes in Portland a couple of months ago and she was sold. She likes to ride improved trails with a 15pound pup in the front basket, the foot is/was really limiting her riding.

    Did a fair amount of research looking at different frames and power trains to work up on, considering her ride is pretty new and she has really missed her old Giant cruiser style (not the weight or gearing), we initially looked at building up on an Electra Cruiser or other "cruiser" style frame. After a lot of research (which is VERY IMPORTANT), we (she) decided to stick with her existing ride, a 21 speed hybrid frame, add cruiser bars and go with the BBS02 mid drive. This is not a performance ride, it is a comfort/recreational/commuter ride. The Trek Shift2 has a 7x3drive train, grip twist shifters, front fork and seat post shocks, so not gonna be shredding single track, but this should be a nice ride she can take out on a Sunday ride on the improved trails on Indian Bend Wash in Scottsdale, or even out to the flat improved desert trails around town if she gets ambitious. Or she can ride along with me on my road rides and bury me with her e-power.

    My background...totally new to e-bikes. Have wrenched a fair amount on my rides over the years, even built up a resto classic Motobecane way back in college, my daily ride until "liberated" from my back porch just before a final exam. Have been riding since, but more semi-seriously recently since the knees are wearing out and to support my eating addiction. Have a decent road (Trek 5200) and trail (Breezer Repack Pro) rides and have been riding off and on 20+ years. Anyway, have OK, but not super knowledge on bike wrenching. is the "before" pic:

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    Last edited by thedadude; 07-03-2017, 08:54 AM.

    Now the fun begins....

    Ordered the following from LUNA:
    BBS02 mid-drive motor,
    750C Display,
    52V 13ah "Botttle Battery" with frame mount bracket,
    Gear Shift Sensor,
    3 level 52v charger,
    Left Side Twist grip throttle,
    Luna wrench,
    Went with the "standard" replacement brake levers with electronic cutoff.

    Package was received after about a week, but short the wrench unfortunately with a note saying "would be shipped separately". Figured that would not be a big deal and follow along in a couple of days, so started the tear down.

    Also ordered a spare set of cables (brake and shift) from AMZN, along with some shrink tube and wire wrap for cleaning up the cable harness.

    Also, ordered from AMZN a set of Sunlight 28" wide x 4" rise x 8" setback cruiser style bars. Since the bride rides with a front basket mounted on the bars and frequently has a 15# pup in said basket, the cruiser style bars made a lot of sense. Should be able to lower the adjustable stem, moving the bars further out front and lowering the basket, giving her improved ride stability with the wider spread on the bars. This will be important since she will have another 20-30# of motor hardware and battery, along with the pup to manage while riding. The wider cruiser style will also better accommodate the hardware store mounted on the bars (left to right: grip twist throttle, rear brake lever, PAS button pad, bell, 750C Display, basket, beverage holder, headlight, right brake lever, gear twist shift with shift sensor mounted at head of shifter).

    Once I got the hardware, I started laying out the parts and pieces, the first challenges became apparent.
    1. The wire harness did not appear to accommodate the additional Gear Shift Sensor purchased.
    2. The wire leads from the brake levers are not gonna long enough to reach the main wire harness on the wider spread of the cruiser style bars, especially with the 750C display is centered. The PAS button pad would also be far from the grips.

    A trouble ticket e-mail note to LUNA helped resolve some of these matters.
    1. Apparently the manufacturer has redesigned the wiring off the motor and does not provide a separate "lead" for a gear sensor from the motor. LUNA said they will ship a "Y" connector, which can be mounted to one of the brake leads and allow the Gear sensor to actuate/cutoff to provide smoother shifts.
    2. The wire harness is designed to minimize the excess cable and designed around standard 24" bars. The wider bars can be partially accommodated by "shifting" the display location to the left side. This gets the display panel close enough to the left bar end to locate the PAS buttons near the shifter/brakes. It also allows the left brake lever lead to reach the wire harness.

    So, I had to order 1 additional brake sensor line extender (8"), and Luna is suppose to be sending the "Y" splitter (which should have been shipped with the Shift Sensor). Been a week or so, still waiting for the parts but received notice the sensor extension purchased Tuesday shipped today (Friday). Still waiting for shipping notice that the wrench and "Y" splitter are on the way...
    Last edited by thedadude; 07-01-2017, 09:48 AM.


    • Rider
      Rider commented
      Editing a comment
      What a lot of people do that don't have the third shut-off wire coming out of the motor (and headlight wire) like the latest version of the BBS##, is hook the front brake cutoff to the gear senor and the just use the rear brake cutoff. You always hit the rear brakes first and use it with the front too. But the "Y" cable is an even better solution.

    So...started...with replacing the bars and control wiring...
    Here is a pic of the original handlebar setup, it was already crowded before adding all the e-stuff
    NOTE: beverage(phone) cup holder already removed and basket already off but the basket bracket is still on:
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    Also the light bracket only is on the right side, no light.
    Last edited by thedadude; 07-01-2017, 09:50 AM.


      I was looking forward to seeing your build since reading an earlier post about the project. Looks like a fun build. Sorry to hear you've run into a few snags. At least it's mostly a parts issue and not a more serious fitment issue, right? Doesn't make it any less frustrating though.

      I've just tackled my first two BBSxx mid drives and I got lucky-no trouble! I also did not spring for the gear sensor. Quickly tapping the ebrake lever without even engaging the brake itself does the same thing as the gear sensor. It allows just enough time to shift and pedal it over to the next gear before the motor kicks back on. It's fun for me - feels like quick shifting a mini motorcycle. I could see some other people finding it quite aggravating though.


      • thedadude
        thedadude commented
        Editing a comment
        Mostly parts...yea, so far been a pretty clean build...but still some issues, more to come as I document below.
        Just need to be open minded and work with what ya got. I am being super careful on this first time build as it is new to me, and I don't want to thrash a $400 + motor or battery by being dumb.
        As for the shift sensor, wanted to be sure this ride is user friendly for the bride, so seemed like a good idea to avoid motor load on shifts and keep it simple by adding the shift sensor, I probably could do without it, but then I use to drive an old VW bug with no clutch for months, all I needed to do was be sure to park it facing downhill, but that is me.
        Last edited by thedadude; 07-01-2017, 05:50 AM.

      Now the fun REALLY begins...tear down!
      Started last Thursday to tear down the original bars and front drive train.

      Pulled the hardware off the old bars, then repositioned the bar stem. The Shift2 comes with a nice adjustable bar stem, so was able to rotate it down and effectively lower and shift the bars forward. This was really nice when going from a slightly setback hybrid bar to a full sweep cruiser style, it should help with control and lowered the center of gravity on the basket.
      Then threw on the new bars and started adding the e-controls. This took a while and several fit/adjustments test configurations to get a setup that would work. The wider spread on the new bars stretch beyond the length the wire harness is designed for, so If using cruiser style bars one must add at least 1 if not more wire extensions to get all the parts to fit and work. Also had to "offset" the display, so the PAS control pad was close enough to the left side grip to use the control without taking hand off.
      Here is a pic of the new bar set, with some of the new hardware set on:
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      Last edited by thedadude; 06-30-2017, 06:05 PM.


        Next...the drivetrain.....
        Started by yanking the front derailleur, the twist grip, and pulling the chain. Ran the chain thru the degreaser and ultrasonic jewlery cleaner (does a great job, don't tell the bride).
        The pedals were easy, just remember they are opposite threaded on one side. Then crank arms, with the right tool (which I had but forgot I did), were easy after trying for an hour with the WRONG tool. The Park Tools crankarm puller is the only way to go:
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        Once the crankarms were off, pulled the chainring cluster and removed the bottom bracket retaining collar, no sweat, but once again, had the right tool for the job (remembered I had one this time. Also, there was a plastic cable guide located on the underside of the BB shell, which guided the front DE cable around the bottom of the BB. This was held on by a phillips screw. Pulled that off, and that completed the front drive teardown.
        Last edited by thedadude; 07-01-2017, 09:55 AM.


          So, now I am ready to test fit the motor, and here, it begins to get a bit challenging. The Shift2 has a 73mm bottom bracket. Since the BBS02 standard body is designed for 68-73 I figure I am fine. Pulled the bottom bracket cleanly, pulled the shifter cableguide off the bottom of the BB shell, and set the motor into the bottom bracket. All looked good, until I started to stack on the retaining yoke, collar nut and jam nut. The motor came with hex head bolts for the 68 mm shell, these were too short. See pic:
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          After some fumbling and a note to Luna Tech support , I found a box with some longer unused bolts and washers in the bottom of the shipping box, I thought...PERFECT! they thought of everything! Tried them out on the motor. There are two threaded mounting holes on the motor frame that bolt the yoke to the motor. One hole on the motor frame is threaded thru, the other hole bottoms into the motor housing. Unfortunately the longer bolts were too long and would bottom out if fully threaded onto the 73mm shell. The 6 washers would work OK as spacers to fill the space between the frame and the yoke when tightened, but one of the bolts was too long, 2 bolts were too short....felt like Little Red Riding Hood.

          So, went out into the junk parts box, found an old bar stem with the same thread and a bolt length RIGHT in between the 2 sizes provided, got lucky and it did the job!
          The problem now is...I still do not have the promised "Luna Wrench" which I now need to tighten the compression nut onto the bottom bracket, BEFORE tightening the yoke mount bolts and re-assembling the chain side crank arm, so I am now stuck waiting for a tool.

          One other note: After review of other threads and before final assembly of the chainring, I pulled the motor and removed the final drive gear cover (7 phillips screws and it pops right off). As noted in other threads, the final drive gearing is shipped pretty "dry" from China and gear failure seems to be a common issue on the Bafaang motors (I may be a NOOB, but want to avoid foreseeable problems). There was some, but not much, grease inside the gear cover/housing. So, I supplemented that by adding some Park "Polylube" in the void space between the housing and gears. Here is a pic after pulling the cover, I've started to add grease in this pic:
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          This is not a Luna issue as they sell what they get from the manufacturer. Hopefully this will extend the life of the gearing, allow the motor to run a bit quieter and should help the drive train run better, only time will tell.

          Once I had lubed the drive gear, threw the cover back on, reset the motor into the bottom bracket, added the yoke and lock nut (hand tight), installed the chain ring & re-installed the chain. Then threw on the left crankarm but can't throw on the right side arm on until I get the lock ring and yoke tightened down, but motor install is now 95% complete.
          Attached Files
          Last edited by thedadude; 07-01-2017, 10:21 AM.


            So, I moved on to the battery install, I also checked with the Luna guys, they said the wrenches were still out of stock but expected this week and they will ship ASAP. Really good communication with/from them, they have been very helpful in resolving what are really very minor issues. Just anxious to get to the finish line now the end is in sight!

            Since I was stuck on the motor build, I went on to installing the battery....the next challenge. The Shift2 has bottle cage lugs mounted on the top "downtube" which would make a perfect mount for the bottle battery...except, they are mounted relatively high on the top down tube and unfortunately the countersunk holes on the battery mount bracket are located relatively low on the mount. As a result, the top of the mount would hit the stem head tube.

            See Pic below, as you can see, the top of the bracket would conflict with the head tube:
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            My first solution seemed elegantly simple. The mounting holes are offset toward the bottom of the connecting bar. I thought, "just flip it" and it will be perfect! I pulled the top and bottom ends off the bracket, only to discover that one end (the bottom) has a chamfer routed out of the bottom of the connector bar. As a result, it cannot be "flipped" ;-( .

            So, went on to Plan B. Since the slotted holes for installation are countersunk you just can't simply "drill it out" to add a hole. Fortunately I had a flat bottom bit that matched width of the larger diameter countersink and I was able to borrow a tabletop drill press to get the countersink depth right to add a 3rd hole/slot to the connector bar. I kinda goobered it up, but was able to get a countersunk slot, very sloppy, but somewhat similar to the OEM holes. In the end, it worked very well, and the crummy machine work is out of sight thank goodness under the battery. Here is a Pic of the bracket as installed:

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              Now I am getting REALLY REALLY CLOSE...I am waiting on parts/tools at this point. I have the motor "soft mounted" (can't lock it down without the wrench), most of the wiring is installed, but I'm stuck waiting on the shift sensor "Y" and a brake sensor extension as the right brake sensor wire will not reach the main harness. I am also still a bit confused on the Gear Shift Sensor install. So, what can I do now? Decided to work on cleaning up what wiring I can. Since the wiring was a bit messy, I had decided to get some spiral wire sheath (3/8") for the bar wiring. I ordered it off AMZN along with some shrink tube to close-in/waterproof the wire plug-in connectors. The only one I am really concerned with is the main connector to the motor as it locates below the downtube, right behind the front wheel so it will catch any water thrown by the front tire. Once this stuff had arrived, started on the wire cleanup...

              Shift Sensor: In discussions with Luna Tech support they say Bafaang used to provide a dedicated wire for a shift sensor straight to the motor but Bafaang did not provided this on the last shipment (only 3 "wires "come off the motor; controller, battery, and speed sensor). The new solution is to just connect the sensor with a splitter "Y" to a brake sensor wire. That is great, except the gear sensors I have seen in my research are mounted on the chain stay, nowhere near the brake sensor cables. So do I need to run a wire all the way back there? Nope, you can put it anywhere on the shift cable. Once again, Luna Tech have been very helpful resolving dumb questions from a Noob.

              So, next question, where to stuff this block of a sensor? Good news is it can go anywhere on the shift cable line, bad news is, as noted earlier, this bar set is already full of hardware. As noted previously, and the wider bars were already stretching the limits of the runs. I had ordered spare cables "just in case", and now it looked like they might come in handy. As it was, the shifter cable was a bit tight, but functional. Since the shifter cable was already tight, adding the length of the shift sensor could help that situation, but would require a longer cable. So, I pull the old cable out of the sheath, re-threaded and installed a new, longer cable, with the sensor mounted right onto the end by the twist shift. This solution made for a nice clean run. The sensor looks to be a part of the shifter and is discretely buried in the hardware behind the brake lever. Also, adding the length of the shift sensor also helped lengthen the tight shift cable run as a result of the new wider bars. This was a win/win essentially eliminating any tightness as the shift sensor was almost the same length as the additional bar width and it discretely located on the bars near and behind the brake lever wire and cable. This should clean up nicely once I get the "Y" from Luna to connect the right brake lever and shift sensor to the main harness lead.

              Here is a pic of the cable thread layout. Note: Added a cable sheath ferrule between the shifter and the sensor to mate the shifter and sensor components:

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              And here is a pic of the final sensor install, the right brake sensor wire and shift sensor wire are just hanging there now, waiting for the "Y" connector to mate with the main harness:

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              Unfortunately, I cannot complete the bar wiring until I get the "Y" and extender....Soooo close! The good news is by connecting the "Y" to the right lever, I might not even need the wire extender...can't wait to get these last few items! Soooooo close!

              On to the speed sensor. This was an easy install, the sensor provided is quite nice with an adjusting slot to get the wheel offset length right. ran it down the left chainstay (opposite the shift/chain side), and added a couple of zip ties, then threw on the magnet once I had it close. Now ready and just need to fire up the motor to check that sensors are working, but don't want to start the motor until it is locked down (wrench?) onto the bottom bracket.
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              Last edited by thedadude; 07-01-2017, 10:33 AM.


                Nonsense! Put some large zip ties around the motor and the downtube in a cross pattern and blip the throttle once or twice in a low gear.

                ...or don't listen to bad advice from someone who gets excited at the prospect of building e-bikes. I usually bench test my motor before mounting it. I get all the excitement without taking any risks that way.


                  The wrench pretty much sucks. Order the socket instead.


                  • Rider
                    Rider commented
                    Editing a comment
                    Yeah, the California ebike socket is nice. If they have that in stock, maybe they can rush that out to you and just cancel the out-of-stock wrench. Just a though. It does cost more...

                  OK, back to the last few parts and pieces in this past week, while I was out of town. The "Y" splitter for adding the shift sensor, a brake sensor/speedo cable extender (which it turns out now I do not need, as the splitter alone is long enough to do the job), and the elusive LUNA wrench. Now I can tighten down the motor, finish the cabling and should be done. Thanks for the suggestion about the socket, but this is a "one-off" build and hard to justify a $50 single use tool...(though I always like to write off a new tool to a job, that one is hard to justify).

                  Thanks also to Luna for getting me the last parts and pieces...though they should include that "Y" with the shift sensor standard as a "kit". It should be a clean build with the sensor by the lever though! Thanks for the suggestion, I had only seen them mounted on the chain stay in other threads. Putting it by the lever should be a more protected location too, thanks for the feedback.

                  I am also cleaning up the wiring and adding some "bling". Went ahead and bought some shrink tube and plan to seal the wire socket connectors with it, they look good and tight but can't hurt (can it?). The only one I am truly concerned about is the main harness extension, it runs under the down tube and will catch any garbage, sand, mud, water the front wheel throws up. Also got some spiral wire sheath to clean up the wiring on the bar set.

                  One other minor complaint/issue to note. The battery case as shipped, appeared to have been victimized by a box cutter. There are a couple of sharp scratches in it that look like they may have come from cutting open a shipping box. Not a material/functional issue, so bot a set of the "Sharkskin" battery decals that color coordinate with the ride and plan to cover the scratches with bling. They are not made for the bottle style battery, but should look ok with a bit of trimming.

                  Time to go to work pics to follow.


                  • Rider
                    Rider commented
                    Editing a comment
                    I bought my Cali-ebike Socket after I did my build, because I struggled with a hook end "C" wrench to install mine. Kind of roughed up the notches hitting the "C" wrench with a hammer. They must have gone up in price. I thought it was $30-35 when I bought mine. Still haven't even used it or the programming cable I purchased, but it's in my tool box when I need it in the future. New cruiser build will be getting a BBS02B soon and a friend is building a Salsa Touring BBS02B bike, so both will come in handy at some point. Glad you got it done with what you had or eventually received. Bike looks great!

                  Well...been a it done! Since my last post, was able to add the shift sensor at the twist lever (you can see it in the 1st pic), and adding the "Y" splitter left enough wire on the harness so that I did not need to add another extension for the right brake sensor too. Then took some pics of the final harness before and after adding spiral cable wrap to clean up the wire harness. The wrap works really well, was able to peel off individual wires as needed.

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                  Attached Files


                    Then took shrink wrap and covered all exposed connectors, that was about it for wiring. The LUNA wrench did the job tightening the final drive onto the bottom bracket, and at that point it was just clean up and add some bling. Had ordered some of the "Luna Shark" decals for the battery. That "bottle" style battery is fairly huge. So threw those on to give it some sizzle and try to make it less the look of a small bomb sitting on the bike downtube. Also installed the speed sensor, and after some finagling, got it set to a good location....

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                    then for some final bling, laced up the wheels with some LED's and DONE!!!! Click image for larger version  Name:	20170710_135722.jpg Views:	1 Size:	240.7 KB ID:	41004
                    Last edited by thedadude; 07-28-2017, 02:04 PM.


                    • Rider
                      Rider commented
                      Editing a comment
                      You're all set for Burning Man! Lol... Lucky gal.
                      Last edited by Rider; 07-29-2017, 02:44 PM.

                    Test rides and minor tweaks since finishing the build but mostly just fun rides have kept us from posting for the last week or two...
                    Have had a couple of minor issues...nothing serious, though I do have some questions regarding the controller and setup which I will post in that forum.

                    She has been TOTALLY impressed with the power, speed, quietness and function of this machine. Typically never uses more than PAS level 1. On a flat out run it'll do 25mph+ easy and more on a full charge and with the DE in high gear. Keeping the 7sp rear DE gives her a lot of choice for power vs speed, and this 750W motor with a 52v battery system has MORE than enough power for any situation. In hindsight could have probably gotten by with a 48v or smaller, but love it and the mid setup for the gearing. A great ride!!!!

                    For a final test, we went out to San Diego/Mission Bay last weekend. Me on my 27.5" full suspension MTB, the bride riding her new E-Bike hybrid conversion. We took a ride up over Mount Soledad into La Jolla...she slayed me going up the hills. Shoulda run my Garmin to track the ride, but with some serious 5-10% slopes and steeper she had more than enough power to climb. Just a little twist on the throttle a few times but typically she kept it in PAS level 1 and blew me off riding up the hill...easily doubled my power and gave her enough to take on rides she would have never considered before.

                    This was a great build, she now has a ride that she can take literally anywhere and blow me away at will!