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Giant Trance x2 2008 BBSHD build

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    Giant Trance x2 2008 BBSHD build

    I had been on the look out for a donor bike for several months. In the time it takes to research whether a second hand bike is suitable for conversion they get snatched up (generally within minutes of being posted). I wanted to avoid a press fit bracket due to the difficulties in getting adapters and tools, although this turned out to be unfounded. I finally managed to grab a second hand Giant Trance X2 2008 donor bike:

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    I knew this would be suitable thanks to this other post, albeit with some concerns about the battery fitting:

    I ordered the following from luna mate aus:
    - BBSHD 68-78 mm
    - luna wrench
    - 52v 14ah Samsung 35E AU
    - DPC-18
    - 42 tooth narrow wide chain ring
    - brake sensors

    As it turns out the kit comes with what looks like a press fit adapter. I wish they had made this clear on the web-site - it would have made things much easier.
    I also ordered a gear sensor from aliexpress as luna was out of stock.

    The bottom bracket came out trivially thanks to the hollowtech cranks - just needed to use the luna wrench and nothing more:

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    I replaced the tyres with some schwalbe super moto x 26"s. They are technically a touch bit too big but they fit ok and are much nicer to ride on the roads with. I then re-routed the rear derailleur cable to follow the same route as what the front derailleur did, to give me more room for other cabling and battery mounting.

    Next was the battery test fit. It was tight but the sizing up I had done with a cardboard template gave me confidence it would fit. Another tip for luna - make these templates available for download to print and test out. I had to work off the measurements to make my own. It was tough to determine if there would be room for both housing the battery and enough room to remove it from the bracket, but in the end it worked out ok (see final pic).

    I may need to add some more nutsert/rivnuts into the frame to hold the top of the bracket in place. Removing the battery can be quite difficult because the bracket lifts with the battery, giving less room for removal. I measured incorrectly initially and had to mess with filing and cutting the bracket - this turned out to be unnecessary, as you can see:

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    I also hacked together a solution to hold the top part of the mount to the frame without requiring a new nut rivet:

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    The motor went into the bracket fine, but it took me a while to notice it was rubbing on the rear swing arm. I now understand what was mentioned in that other post. You can see some of the motor being ground off in this photo:

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    I put a spacer on the chain ring side and there was enough clearance, but it presented a new problem. The top of the motor no longer pressed against the bottom of the BB - it hit the mounting point instead (i.e the red line hitting the green line in the photo below, ignore the inner tube rubber). I had to either;

    - Use a thinner spacer so it wouldn't move across further and not hit here anymore (I didn't have one)
    - Use no spacer and grind the chain ring mount so it would no longer rub
    - Grind the mount point down so it would no longer rub (seems like a bad idea)
    - Put some padding on top of the motor so it would hit that instead of the mount point

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    I ended up choosing to put a ~3mm washer on top of the motor with a single layer of inner tube. The BB now makes contact with this washer rather than the mount point. I may revisit this decision later. If anyone knows whether grinding the chain ring mount (where you can see it rubbing) is ok let me know. Or if there are thinner spacers than what are provided as stock. I used a zinc plated washer on top of the motor, but would like to replace it with stainless steel later.

    I have seen report after report about motors moving and not being held securely so I wanted to do something about it up front. The design of gripping the BB with some ridges seems dodgy, especially given the torque this thing puts out. Sure enough the motor slipped in place and caused all sorts of wear on the BB after just a couple days.

    I have seen the 'stabaliser bar' for full suspension bikes, but this seems a bit flawed given that it relies on securing to a rivet nut that are prone to working loose. So I haven't rushed out to buy that just yet (it's quite expensive). I noticed there was a little hole above the triangle on this frame and figured I could make use of this somehow:

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    My first attempt was to use some strapping combing with some inner tubing to try and secure the motor up. This didn't work too well and there was still a ton of movement. I got rid of the rubber except for a single layer plus the washer. I also added a few nuts and bolts to the strapping to try and tension it up after installation. There was still a bit of movement, but I torqued up the lock nut and this movement stopped, I then added another bolt and nut to the strapping to increase the tension, plus a washer for the bolts to press up against. Hopefully it's pretty fixed in place now:

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    Despite what it might look like in the photos, there is plenty of clearance for the swingarm.
    The fixing tape is galvanised steel - I'd really like to replace it with something rigid and stainless, but I suspect that will be very hard to work with. I think I'll just keep an eye on it and change it over when I start noticing any movement or rust.

    I then added the gear sensor. I wasn't sure if I needed one but after adding it and taking a test ride I'm glad I did. It feels like driving an automatic car.

    Final pic. Just need to install the brake sensors and try out a few different handlebar/stem/grip/seat options. I'd like it to be more of a 'cruiser' style. Basically a full suspension commuter type of bike with an emphasis on comfort. We'll see;

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    Last edited by aurover; 3 weeks ago.

    Nice build aurover! If you are looking for some handle bars that go with the long stem, this one worked well for me Hunter smooth move “comfort bars”. They are a worthwhile upgrade if you are looking for a more upright position. Here are the dimensions: 750mm wide, 75mm rise, 15 degree back sweep, 5 degree upsweep. Read this article - basically the Hunter Smooth Move Handlebars, with 15 degrees back sweep, will move the line between the center point of the two grips to just above the center of the steerer tube bolt which is as aggressive as you would want (i.e. quicker steering in technical single track). Cheers!


      Hi, can you tell me the stats on this build. I have just purchased a 2017 Giant Trance 2 that I will add electric too. What is the top speed and range on your set up? Do you see any issues with this electric kit.

      Your post is very helpful, thank you for the pictures and descriptions you provided.


        Top speed is probably around 60kph on the flat, though that is pushing it. It would be possible to get faster (or slower) with different gearing.
        However I speed limit it to about 35kph as that is plenty fast enough.

        Range is pretty good, more than I need. I would pick a smaller battery (and perhaps just a BBS02) if I were to build again. Possibly a cheaper third party battery, though it may not have the same quality.
        I haven't done a range test, but I think 40km would be quite possible. Of course this depends on hills, speed, PAS etc.

        The default programming for the motor is ok, but I think the 'crank trigger pulses' is set way too high and I changed it down to 5. I also reduced the start current.

        The chain line isn't great, but I may be able to fix this with derailleur adjustments. However I am tempted to reduce the cassette down to just 4 or so gears with spacers instead.

        The main issue with installation is the need to use a spacer which causes the motor to hit the frame on the mount point. I put a washer on top but this has fallen off - I am going to fabricate a piece of SS that locks into position instead. It is also very difficult to get it installed without movement - the 'stabliser bar' may help, and may also solve the issue with the mount point hitting the frame, but I'm reluctant to use it.


          aurover, Thank you . Why a BBSO2 verses the BBSHD? Also did you purchase Luna battery, and with what volt and ah?


            One last question Aurover, the size. You said you purchased the 68mm to 78mm, also you said issue with motor hits the frame and need spacer. If you did this again, would you purchase a 100mm Bafang BBSHD and use the spacers available. I am getting ready to purchase the kit, but leaning to buying a 100mm with a spacer, specifficallly this spacer.


              I would imagine a 2017 Giant Trance is going to be quite different to a 2008 Giant Trance X2. For one thing the newer model has a press fit BB. I'm sure there are many other differences.

              I think the BBSHD and large battery is overkill for my purposes. The size and weight draws undue attention given the questionable legality - which is frustrating when I intend to use it within the legal guidelines. I just need the extra wattage to get up hills comfortably, but still well within the speed limits. I'm also finding that I am pedalling more than I expected - but I will see if that continues when commuting everyday through summer.

              Regardless, the BBSHD would certainly be the right choice for any kind of offroading.

              I tried fabricating a washer to sit under the frame to avoid hitting the lug, but that just cause the motor to hang down lower. In the end I hit the lug with an angle grinder and shaved a few mm off it. I think it's much better than using a fat washer:

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              The 100mm sized motor has a longer shaft, but I'm not sure if it extends the distance between the chain ring and the lug. As you can see from the photo above, this is the main issue. I doubt you'd want to go bigger as you'd have chain line, symmetry and crank/pedal width issues.

              As it is I've re-ordered my cassette to only have 5 or so gears to improve the chain line. I've also decided to go to 32T as the max gear due to the larger sprocket being in the middle and the derailleur needing to clear it.
              Last edited by aurover; 5 days ago.


                Originally posted by Galanty View Post
                One last question Aurover, the size. You said you purchased the 68mm to 78mm, also you said issue with motor hits the frame and need spacer. If you did this again, would you purchase a 100mm Bafang BBSHD and use the spacers available. I am getting ready to purchase the kit, but leaning to buying a 100mm with a spacer, specifficallly this spacer.
                I used a 2017 Giant Stance, which is very simlar. My build was here:


                I think I used the 100mm one.