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Motobecane Lurch Fat Bike + BBSHD

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    Motobecane Lurch Fat Bike + BBSHD

    Here are the specifics on my BBSHD + Motobecane Lurch Fat Bike Build. I hope these details help someone thinking about building a bike.





    I selected the Lurch because the price, color and size were all what I needed. Plus, I love the lines on it! My research indicated it would work well with a BBSHD 120mm size too. In retrospect, my wife would have preferred a bike with a Bluto front fork.

    My wife and I wanted a way to get deeper into the woods in search of funghi. Also, we live at the top of a large hill -- which kills the fun biking back from a trip to town.

    Last year I built two mountain bikes with 1500 watt rear wheel motors from Ebay. I added some heavy lithium batteries from China. They worked OK at first, but, they are really heavy and not well balanced. They don’t handle our Western Colorado “hills” very well.

    When I heard about the new BBSHD motor, I decided to build two new bikes… fat bikes that would take us up trails and into town efficiently. After building our mid-drive fat bikes, I don’t even want to look at those two rear-wheel drive bikes.

    This first bike for my wife, a size 14 Black Motobecane 2016 Lurch X9 from BikesDirect.com . http://goo.gl/0sq6mV It came in a box that was totally beat up, but, the bike was pristine on the inside! After put together it weighed about 35 lbs.



    We purchased all of the electric bike components from Luna and chose the Bafang BBSHD 120mm version. It was definitely the right size. Thanks to https://goo.gl/03KCZu and https://goo.gl/20lOIz for the guidance on that… We also ordered the extra spacer kit.

    I didn’t have much experience with bikes and had to invest in some tools. I trolled forums and blogs, watched youtube videos and constantly referenced Zinn’s Art of Mountain Bike Maintenance. I will stick some of those links below.

    Bottom Bracket Removal. It was hard to get the crank out of the bottom bracket! It required some swearing, grunting and a rubber mallet. I had to give it 110% to get it loosened. I needed a large and strong allen wrench, first, to get one of the cranks off. Then, a bottom bracket wrench to loosen the bottom bracket... and then a crank extractor tool thingie to remove the other crank. nearly took it to a bike shop to get the bottom bracket taken apart. https://goo.gl/q5PpTd has a good tutorial.

    Installation of the Mid-Drive - It slid right in! I had to add lots of spacers on either side (definitely order an extra spacer kit for this build) I used all of them, half on the left side and half on the right. I put red Loctite in between all the spacers and blue “Loctite on all threads before tightening down. I also put a ball of Loctite Repair Putty where the motor touched the downtube (thanks Alan https://goo.gl/vhVMrY )

    Note: I didn’t have a Bafang wrench, so I used a rag and a big wrench to tighten down the Bafang bottom bracket. I got a proper Bafang fitting tool later from Luna and was able to tighten it down even more, which pleased me. I Recommend you get one of these tools for your build.

    I screwed on the Luna 42T Chain Ring instead of the Bafang 46T that was included. It works great, and gives enough torque to charge up the steepest climbs and enough teeth to go pretty fast on the flats.

    The chain-line is this build’s weak link, but it works. First gear has a pretty rough angle, and I typically don’t use it. Initially this required two fixes:
    #1) The chain that came with the bike was too short, it wouldn’t even shift into the first 2 or 3 gears. I needed a longer chain. So I bought a 10 speed KMC chain (I think that came with 116 links and I removed 4 of them to get the right size.) You will definitely need a chain tool to remove the links. Also a Parks Tool Master Link Plier is really pretty handy for taking chains on and off a bike. I was glad I had one of those!

    #2) Once my chain was long enough, it liked to jump off the tracks on first gear… So, I added a N-Gear Jump Stop Chain Guide/Watcher 29mm - I installed this and it was too short to actually do its job, arrgh. I ran up to Walmart and purchased a little metal extender doohickey. (it was stocked with door hinges -- “2” zinc plated mending plates” and cost $1.) After installing that, it looked janky, but seems to work pretty well.



    After that I did a lot of the standard stuff:
    • Changed over to the Bafang Brakes
    • Added the speedometer
    • Added the gear sensor (I recommend you buy one of these)
    • Added the throttle and on-off switch and computer.
    • Hooked up all the cables and zip-tied them down
    The next problem is that the shark-pack battery didn’t fit. The interior of the frame on the size 1 bike was too small to line up the water bottle holes with the battery holes. But, I could just barely wedge the battery into the frame and then used three good velcro tie-downs to hold it into place. It actually seems to work pretty well!



    At this point, it was ready to take for a ride. I gotta say, this BBSHD mid-drive thing is a hell of a lot better than those wheel-drive systems. The weight, while heavy, is nicely balanced and I don’t notice while riding it. It has tremendous torque, is quiet, and doesn’t get too hot. I can easily go on a 20 mile round trip with my battery. I typically use Pedal Assist mode because I like the ride.
    Attached Files
    Last edited by Blizzard; 08-11-2016, 05:35 PM. Reason: fix photos

    #2
    Next, some accessories: Also, I had to learn how to adjust brakes. I think the brakes that came on the Motobecane were pretty good. They get good reviews online. I spent several hours adjusting and re-adjusting the disc brakes so they would work well… there are some good youtube videos on that. A T25 Torx wrench made this a lot easier.
    Finally, one more thing really had to be done… the cabling, especially between the battery and the motor. It was excessively long, and, it used Anderson Power Pole connectors. I hated the way it sparked every time I connected it. So...I bought a five pack of male and female XT90-S anti-spark Connector Plugs. I watched videos on how to solder and bought a cheap soldering iron. I bought some marine-grade adhesive lined heat shrink tubing. I practiced with a few to make sure I knew how, then, I cut my motor and battery wires down to the perfect size and re-soldered the new connectors and carefully sealed them with the heat shrink tubing to make waterproof. That really cleaned up the bottom of the bike and made it look a lot better.



    While I was at it, I also made a 4 foot “extension” cable that would allow me to carry a spare battery in a backpack and connect it. Just in case.
    Random Tips:
    • Rubbing alcohol makes it easy to get the grips on and off of the handlebars.
    • Buy zip ties in larger quantities. You will go though a lot of them making adjustments and improvements. Put some in your bike bag for emergency repairs.
    • Religiously wear pants leg protectors. The chain ring is exposed and grabs your pant legs, and then you break a chain, and have to walk home.
    • Get a nice allen wrench set... you will use them all the time.
    • Get a bike stand, they are pretty handy! I got a RAD Cycle PRoducrts Pro https://goo.gl/uxPHrJ - it works, but I always feel it is going to break under the weight. I wish I had gotten a better one.
    • Get a bike toolkit. Some specialty tools I needed were a Chain removal tool, bottom bracket wrench and crank remover. I got the Spin Doctor Essential Bicycle Tool Kit and it seems good. https://goo.gl/6zWeU5
    • Be ready for things to go wrong if you haven’t done this before. I left out the wrong size chain I installed at first (9 speeds don’t work well on 10 speeds!), the broken derailleur cable, the frayed cable ends, the skinned knuckles, the upside down handlebars, etc.
    • Thank god for Amazon Prime.
    Parts List - Stuff I needed
    • Bafang 120mm BBHSD $669
    • Luna Full color Display $45
    • Gear Sensor for Derailers $45
    • 52V Panasonic Shark Pack 13.5ah $476
    • 300W Luna Battery Charger $89
    • Luna 42T Chain Ring Adaptor $40
    • Spacer Kit for BBSHD bottom Bracket $10
    • Luna BBSHD Wrench $19 http://goo.gl/aTWyrG
    • N-Gear Jump Stop Chain Guide/Watcher $10 https://goo.gl/ff2GKT
    • KMC x10.93 10 speed 1176 Links Chain $24 https://goo.gl/pqtU6C
    • Parks Tool MLP Chain Plier $14 https://goo.gl/k24fHs
    Other Stuff I used
    • Red Loctite Threadlocker
    • Blue Loctite Threadlocker
    • Loctite Repair Putty
    • Velcro Tie Downs
    • Zip Ties
    • Zinn’s Art of Mountain Bike Maintenance
    • T25 Torx wrench
    • XT90-S anti-spark Connector Plugs (Male and Female) https://goo.gl/O11FyX
    • Soldering Iron and Solder
    Marine Grade Electrical Adhesive Lined Heat Shrink Tubing https://goo.gl/OJWegs
    Attached Files
    Last edited by Blizzard; 08-01-2016, 09:00 PM.

    Comment


      #3
      anyone have a tip on why the inline photos show up as [ATTACH=CONFIG]n13246[/ATTACH] instead of actual photos?

      Comment


        #4
        I posted this topic awhile ago as i was having similar issue.

        http://electricbike.com/forum/forum/...loading-photos

        Comment


        • Blizzard
          Blizzard commented
          Editing a comment
          Thx Rodney64

        #5
        Mr. Nosey here. What did you use red on? I can't imagine where I'd want to use heat to undo my work? I mean that not as a criticism, rather to learn.

        Comment


        • Blizzard
          Blizzard commented
          Editing a comment
          feel free to be critical, you probably know more than me! I added it in-between each spacer/washer and the bottom bracket itself too where it touches the spacers. I wanted to reduce the chance of any slippage there since so many washers were stacked together... and, I didn't have the proper bottom-bracket tightening wrench that fit the Bafang . I used the blue loctite anywhere that had a thread/screw in the bottom bracket area. Oh, I also used the red in my janky n-gear stop extender to try to make it more secure

        • Louis
          Louis commented
          Editing a comment
          Gotcha! I just worried a bit. I had a couple of cals where the builder used red on the M6 bolts and as you know red takes a torch and lots of heat to release.

        #6
        Could you have wedged in a 100mm BBSHD to avoid the bad chain line?

        Comment


          #7
          Hey Blizzard, just wanted to thank you again for your great build thread. I just completed my own Lurch BBSHD with the great info you provided in here! Was curious about your chain size and it skipping/hopping. I put the same chain on you bought, without removing any links and after my first 20 minute ride can't believe how smoothly it shifts and haven't had any skipping/hopping. My bike is a 2017 which has different wheels and the SRAM GX drivetrain, so perhaps it's totally different, but after adjusting it goes into all 10 gears and seems to have a pretty straight chainline.

          How's your chain/drivetrain holding up with fewer links? I'm also curious to know if you have a close up of how you mounted the motor, especially the drive side spacers? Not sure I did mine the right way. Here's a link to my thread with pics of how I did it. http://electricbike.com/forum/forum/...ilds-an-e-bike
          Last edited by 1badfattie; 09-17-2016, 11:45 PM.

          Comment

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