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BBSHD - 2006 Trek 7.2 FX Donor Bike Build

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    BBSHD - 2006 Trek 7.2 FX Donor Bike Build

    This was my first e-Bike build and ride and wow, it’s so fun. I started this build to make an old bike I had useful again and it’s just so much fun I’m not sure I can go back to my road bike. Details below as well as a few lessons learned at the end. Quick summary, pretty easy build, kit fits like a glove on my donor bike, had one or two snags but nothing major.

    Donor Bike: 2006 Trek 7.2 FX –Hybrid style bike

    E-Bike Kit:
    Luna Cycle BBSHD mid drive kit
    Upgraded to Full Color Display
    48v Shark Pack 13.5 ah
    Stock Chain Ring (Gave me a pretty good chainline)
    Thumb Throttle

    Upgrades to existing donor bike:
    Schwalbe Marathon GT Tour 700x38c Tires
    I wasn’t sure how large of tires would fit, after ordering the 38’s and installing, I probably could have gone larger, but these feel pretty good on the bike.
    I kept the existing direct pull brakes and added Kool Stop Pads, stopping power seems fine even though they aren’t discs.
    I plan on adding a rear rack, panniers, front light and fenders eventually.
    New bike chain, I ruined the old one taking it off with a crappy chain tool, and it was pretty old and needed replaced anyway.

    Tools I had to buy:
    Bottom Bracket Removal Tool
    Crank Puller (this thing is so satisfying to use it’s worth the cost just to use once)

    Other stuff you might need that I already had:
    A large pipe wrench for bottom bracket removal
    Chain tool
    Lots of wrenches, pliers, allen wrenches, basic bike tools for tire replacement, possibly new bike tubes, zip ties, probably something else I’m forgetting, but that’s about it.

    This build went very smoothly, as mentioned above, everything fit like a glove including the shark pack and the motor. The shark pack is a tight fit, but it fits without issue. I purchased the optional accessory kit for the motor fit that comes with washers and things, but didn’t end up needing any of them. I only had one real issue which was getting the drive side bottom bracket off. It was seized up pretty tight, so I soaked it for a few days in WD-40, then got a big pipe wrench and it came right off (see photo of wrench, once I borrowed that from a friend, it came off nice and easy).

    A few things I was worried about so far have turned out to be no big deal. I was worried my brakes wouldn’t be strong enough, everyone recommends discs. I’m sure disc brakes would be much better, but my direct pulls with upgraded brake pads seem to be good enough, I don’t feel unsafe. Secondly I was worried about not having a front shock, but the wider tires and running them at a relatively low pressure seem to work out fine for the road riding I do. I’ve been comfortable and the bike feels steady.

    The chainline with the stock chain ring is pretty darn good. In gear 8 (hardest gear) I get some skipping, but I think if I remove a link it will fix that. Otherwise it works great.

    I still need to fix the cable routing, I ran out of black zip ties so I used some red ones temporarily, once I get new black ones I’ll come back through and clean it all up. I’m going to add a rear rack, panniers, fenders, and a front light and then I’m good to go I think.

    I have one technical issue that I’m hoping will go away. My battery only seems to be charging to around 80% (according to the display on the bike). I’m still in the break in period so I’m hoping this will fix itself and if it doesn’t, it appears there are a few things I can try to get it to 100%.

    As far as performance goes, holy $*^* this is fun! Way better than I was expecting. I’m a roadie in pretty good shape and just did this for fun, but man it is so much fun I don’t know if I can go back to my regular bike. I live in a hilly, rural area and this is so much fun on those roads. Plenty of power for climbing large hills and it just never seems to stop. I keep it at assistance level 2 mostly, and I’m usually going about 20-25 MPH, all the time, it’s awesome!

    Wife want one now, so I think that’ll be my next build, then maybe a mountain/enduro bike build. I still can’t believe how easy and fun this thing is!
    Last edited by jimz; 06-26-2019, 07:38 AM.

    Look great - thanks much for the build write-up and pics!
    2nd build, 2018 Crust Scapegoat, BBS02 or BBSHD, Rohloff IGH
    3rd build, 2018 Crust Evasion step-thru, BBS02, Nexus INTER-3 IGH
    4th build, 2016 Salsa Marrakesh flatbar frameset, BBSHD, Alfine 8 IGH
    5th build, 2019 Crust Evasion, BBS02 or BBSHD, Alfine 8 IGH
    Other, Electronic throttle lock


      Trek Hybrids, and Comfort bike make great conversions. I would go bigger on the tires since that's your suspension. PB Blaster is better than WD40 for removing corroded parts.
      Those OEM chainrings are famous for dropping chains over bumps. An old front derailer can work as a chainguide if needed. I see you have a 2 leg kickstand. I use those too. The rim brakes will probably be OK. I just run discs because standing water, and rain is a fact of life around here.