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BBS02 on a DiamondBack Overdrive

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    BBS02 on a DiamondBack Overdrive

    My work's office is moving about 1.5 miles further away (and 400 ft further up a hill) than where it is now. I commute on a Specialized road bike, but I know that I won't ride as much after the move given the extra time/effort that will be involved. So (goaded on by a couple of bike-centric coworkers) I decided it was time to try building an eBike. After doing a fair bit of research online, I settled on the mid drive BBS02, and I bought a new 29er (Diamondback Overdrive) for $400 from Nashbar as my mod platform. My intention is to use this primarily (exclusively?) as a road/commuter, so I looked for a frame with a hard tail and a fork that could be mostly locked out. I put some narrow (35mm) commuter tires on it and road it around a bit - seemed OK.

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    I got a BBS02 "kit" from Luna. I put "kit" in quotes because - frankly - it really wasn't (see below), but it was a good deal on the parts I did end up with.

    The conversion went fairly well other than few minor issues.

    Issue #1) My bottom bracket is 73mm but the BBS02 comes designed for a 68mm BB. That meant the locking ring (red arrow in the picture below fit, but the outer locking ring/cover (yellow arrow in the picture below) didn't. My work around for the black ring was to turn it around and screw it on backwards (as shown). The gray ring holds the BBS02 in place (and preloads it against the BB) and the black ring holds the gray ring in place by jamming into it. Without the black ring, the gray ring will work itself loose - so you need *something* there. (Or locktite on the gray ring).

    I can't get the tool on the spline to really crank it down tight, but I used some channel lock pliers to give it a bit of a turn. When I have time, I'll probably take the ring off, and machine off the lip enough it'll go on correctly. A second gray lock ring (part of the $6 "spare parts kit" at Luna) would probably work as a second lock/jam ring.

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    The other problem with the 73 mm BB is the gap between the mounting plate and the BBS02 of 5mm. In the picture above you can see the 5 washers at the blue arrow (1/4" washers, filed to flatten one side so they'd fit) I had to insert. I did this in two places. I also needed longer screws to reach across the gap. (I believe these were M6 screws). When I got to this point in the build I had to stop, and run to a hardware store to buy <$2 worth of washers and screws. This is one place where I say "this really isn't a 'kit' - or the necessary parts would be there..."

    Once I got my extra hardware, and I jerry rigged the black lock ring on, I had no more issues installing the main hardware...

    However, there were electrical issues:

    Issue #2) I bought a carbon shark battery as part of the "kit". When I went to connect it to the BBS02 I discovered I had bare wires and needed to buy some sort of connector to hook on the battery to the motor. Another interminable delay while I searched for a $1 plug. Ultimately I bought a 5 pack from LunaCycle for $5 even though I only needed one (pretty annoying, right?). I got them soldered up and finally the bike was running.

    Issue #3) I had bought a gear shift sensor, but the cable from it to the motor was too short (about 8" too short) - so I needed to buy an extension. Unfortunately, the extensions are only 1m long (~40 inches), so way more than I needed, but once i got it I just looped up the excess cable to try it out. At some point in the future, I'll probably cut and splice the line so the sensor has the "right length" cable on it, and I'll have a somewhat shorter extension left over (or two ends that are waiting for other purposes). Not a big deal, but be aware the gear sensor has a pretty short cable.

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    Issue #4) I would have bought the factory hydraulic brake levers with the eBrake cutoff capability, but they were out of stock when I ordered. I see today they aren't even listed any more. Instead I got the magnetic (hall effect) switches that come with a couple small but powerful magnets. The issue is I can't figure a good place to mount them on the brake levers that came on the bike - so I left them off. By and large this hasn't been a problem riding (since I'm commuting). Stopping pedaling causes the pedal-assist to cut out (with a bit of lag) - and it's not been a riding hazard for me so far. I may revisit this issue to see about some way to fashion a mount (maybe 3D print?) for the magnets. If you're riding off road (trail riding) I suspect that you're going to want to be sure these are installed.

    By and large that's it - I put it together and it rides great. Let me describe some options I took and what I think about them now:

    Since I am aiming to commute, I built the bike for speed (not power/torque for hill climbing), and I went with the largest chain ring (52T) I could. Even at that, I still mostly live in the smallest 4 or 5 cogs in the cassette. I'm glad I didn't go smaller than the 52T. The middle of the cassette lines up well with the chain ring (a bit hard to see here)

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    I have the c965 computer - doesn't seem to be an option at Luna any more, but I am happy with it. Might have opted for the full color display, but $45 seemed like too much of an upcharge.

    The crank arms that come with the BBS02 are 170mm. After riding a bit, it felt "small" to me, so I swapped back on the 175mm's that came on the stock bike. I had to unscrew the chain rings from the right side (still have the 4 arm spider) and this feels better. I couldn't find a right hand side 175mm arm with the square taper hole, so I either need to live with the spider, or perhaps machine/grind it off. Maybe you could just get another left arm - and then use two left pedals, presuming you don't want clipless or something else that's "oriented" R vs. L...

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    As noted in other posts/blogs, the BBS02 Pedal Assist takes a bit of getting used to, but it's not that bad. Think of it as "cruise control" - in PA-Level1 the bike wants to go ~15 mph - no matter how hard you pedal. If you're going less than 15 mph the motor kicks in to help. If you're going 15 mph or more, there no motor assist. PA-Level2 = 18 mph, PA-Level3 = 21 mph, etc. The exact speeds for each level do seem to be impacted by what you set as the top speed for the motor. As you increase the top end speed, the various levels seem to spread out (and increase) a bit.

    It also seems like if you exceed the "PA-Level" speed that the motor is working against you. In other posts I've seen people speculate that you're actually back driving the motor (or some portion of the gearing / clutch). That seems very likely to be the case based on how it feels to pedal.

    In the end this was a fun build and an even more fun ride. However the frustrations that came with Luna leaving out $3 of parts needed to actually be “a kit” (when I paid $1100 for the kit), were really unnecessary. If you’re buying your parts from Luna, you probably want to go get the aforementioned items (2 longer screws, washers, and some connector – I used XT-60), or you’ll be cursing them as well…

    Nice set-up!

    I think the main reason that Luna doesn't include a plug pre-soldered to the battery and/or motor is that there is such a wide variety of batteries used, so many people change them anyway.

    The longer bolts and spacers are pretty hard to have in the kit as every bike is going to be a little different. Unfortunately, in the bicycle world, VERY little is standardized, there are odd ball threaded fasteners (like BMX stems, kickstands, ) and differences between different shapes & sizes of frames that would make it impossible to have enough different bolts/spacers.

    I had to play with the wiring a bit before I realized I had more slack to get things together where I thought were too short (I had the display on backward at one point and lacked long enough wires till I put it on correctly, and voila! It all fit. I was originally going to put on a different pair of bars before I discovered that. : )


      One clarification - the washers I used for the spacers were 3/16" not 1/4"... still needed to file a bit off one side to get them to fit up against the motor.


        To reply to LI-ghtcycle, with regards to the connectors, I'd agree - if I were buying parts from different vendors. But I bought a motor and a battery/sled not only both from Luna, but in a package they called "A KIT". If you buy a kit don't you sort of expect every part you need is going to be in there?
        It isn't that hard for them to figure "hey, he's going to need this $1 part too - if he's going actually put this kit together..." and toss it in. It probably costs them 50 cents if they retail for a $1. Even if I threw it away, unused, a 50 cent piece added to a $1100 "kit" seems like good PR.

        Ditto the mounting hardware. Sure there are a few different types, but 73mm Bottom brackets are pretty common. At least have an option for "which BB spacer pack would you like for us to include?" and then toss in the 25 cents of hardware needed to actually complete the build. At the end of the day, their leaving out of $1-2 of (IMO, not unreasonably expected) parts, left a blotch on what would otherwise have been a glowing endorsement.


          I understand, however, unless you are using a nominal frame of a known bike, I would still say it is virtually impossible for any manufacturer to have even 1/2 of all the combinations of hardware required to fit so many different frames.

          Add to the fact that every person is going to need a little larger or smaller frame, prefer a different bicycle style (Fat Bike, Mt. Bike, Hybrid, Road Bike, Comfort Cruiser, etc. etc.) If I were for example to try do too much along those lines, it would honestly be fruitless IMHO, for the same reason that a "mobile bicycle repair" is a very difficult proposition for all but the most simple repairs, even trying to have enough of different sized tires is extremely difficult with out having the full inventory of a shop available.

          The only way I can see a "kit" working for a bike with no different hardware needed from an outside source is to have it designed for a specific frame, and in the end, that is where a complete "turn key" bike comes in.

          A DIY kit is never going to be able to fit all bicycles with out some outside support, but for what it's worth, in my limited experience (around 7 years making my own) building everything from hub motors to friction drives, I have not seen any kit or other system that fits such a wide variety of bicycles with minimal fuss.

          I think your input however will definitely be useful in improving an already good product. : )


            I'm not sure I'm following your point about "so many different frames". The two items I'm talking about are:

            1) spacers and screws to handle the bottom bracket width
            2) an electric plug connector (xt-60 or similar).

            In the case of the first item, there aren't "so many different frames" to deal with - none of the frame dimensions matter other than BB width, and for that, the number of expected sizes is limited. Most bikes in America are probably either 68mm or 73 mm (or fatty 120mm). The BBS02 comes set for 68mm, so all that's needed is one set of spacers and screws 5mm longer and you've probably doubled (or more) the people who can build the kit without scratching the heads and having to run to a hardware store to buy $1 of metal. Throw in a pile of 1mm washers (what I ended up using) and maybe two or three sets of screws of various lengths and you've got pretty much every BB size covered down to the 1mm increment for $2 of extra parts.

            In the case of the second item, there's *no* aspect of the frame that affects it! It's just another $1 part that makes the kit "ready to go" instead of needing to spend hours (days in my case) finding and ordering one small part to complete the build. If someone buys a motor *and* a battery in the same order, comp them an xt60 - how hard is that??

            Heck, I could be *charged* for this "washer and screw option" with the kit, and a single xt-60 - pass along the $1-$2 cost - I wouldn't mind. The annoyance of getting 95% of the way to "rideable" only to find that tiny parts weren't included was exceptionally frustrating, and to realize that I had to spend all of $2 to complete the build after paying well over $1000 for the "kit" added insult to injury.

            I was once told "a lot of money is a motivator, but a little money can be a demotivator" and I think that's true here. If I had to pay $5 extra for a "complete-your-build kit" package consisting of half a dozen spacer options (most of which I throw away unused) and an xt60, I wouldn't have batted an eye - I was already into this for $1100+. But making me waste a day to run around and try to figure some "washer solution" and realize that the purported "kit" wasn't complete - presumably because the vendor couldn't be bothered including $1-2 of parts really sticks in my mind (and my craw) and seems like bad marketing.

            All this said, I'm using the bike to commute to work and probably 15 people in my office have "test ridden" the bike (in the parking lot - including the hill to get up to our parking lot) and without exception everyone comes back from even a 2 minute spin around the lot with an enormous sh*t-eating grin saying "holy cow that's a blast!" It's a great setup, and so far I love the ride. I expect there will be at least a couple more who will build based on this. At least I'll have xt60's for them (had to buy 5 in a pack at LunaCycle) and some left over washers... ;-)
            Last edited by Solana Mark; 10-12-2016, 07:08 AM.


              I agree that a few more "bits and pieces" should be included in the "kits". In similar fashion, I purchased a Luna Eclipse chain ring (which is awesome) and a 5mm spacer. When I got the chain ring and bolts, the bolts that were included were sized for installing the chain ring without a 5mm spacer...So I had to go to my local hardware store and buy SS allen bolts that were 5mm longer than the ones I received... Seems obvious to me, that if a customer is buying a 5mm spacer with the chain ring...that the attachment bolts should be longer? IMO the supplied bolts a were just too short to provide full strength with spacer installed.
              All of that said, I am a big fan of Luna Cycle, but we need to give honest and constructive feedback to help them get better. Not doing so is not doing them any favors.

              Finally, If you have not already done so, you should research BBSXX re-programming methods and options. I have completely changed the response profile of my HD with programming and it improved my riding experience immensely. I no longer have "cruise control". FYI...You will void your warranty when you re-program.


                For kits not to come with the proper battery connector? Sure maybe the first couple of kits made by Luna---after selling hundred or thousands of kits?? If they have ever done an install themselves then they know what the kit needs...


                  Thanks for info, im going to do this to my Diamondback bike. What is your top speed. Im considering a 42 tooth or 48 since I have hills in my area


                  • 73Eldo
                    73Eldo commented
                    Editing a comment
                    This thread is from 2016 and it looks like the people in it have not been on the site since 2018 at the latest so you probably won't be getting a reply from them. For speed you want bigger (46+) in the front and smaller in the back (11). For hills and you should define hills and perhaps your weight you want smaller (-42) in the front and bigger in the back (36+). You should also define what you hope to get for speed. If you hope to cruise in the mid teens just slightly above non athlete bike speed no problem. If you want to cruise over 20 mph and you weigh over say 200 that takes a little thought. If you want to maintain 30 mph then that is a whole different set of considerations.