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BBSHD on a GT Zaskar Comp 29er. Plus my recommendations of what works and doesn't.

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    BBSHD on a GT Zaskar Comp 29er. Plus my recommendations of what works and doesn't.

    This write-up is not so much about the bike or my build but about the things that worked and things that should probably be avoided. I have over 750 mi on my ebike and I've learned a few things not to do so I thought I'd share. A few things about me: I'm a big guy about 220 lbs, with a motor, battery and a backpack I think I'm putting 260+ lbs on this bike. My commute is 34 mi round trip. I love it.

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    GT Zaskar Comp 29er
    68-73mm (Standard) BBSHD
    52v Pansonic 11.5ah Dolphin
    Luna Full Color Display DPC-14
    Stock thumb throttle
    Hydraulic Disc Brake Sensors
    Gearsensor for Bafang Mid Drives
    Seat Post Mount Bag with tools and parts

    Installing the BBSHD in this bike was easy. There are no issues with the bottom bracket or battery mount location. My build took somewhere between 4-8 hours. I was riding the bike within 4 hours but I took more time afterward to add the extra components like the gearsensor and brake sensors. The one thing I was not able to do on this bike was use the Luna Mighty-Mini 30 tooth chain ring because the chain line was too extreme.

    I didn't exactly choose this bike, I already had it. I've been a hardtailer all my life and I thought it was time for a full suspension bike for my trail riding so I converted my GT Zaskar. I've been riding this bike through medium all-mountain trails. I really put it through it's paces and learned it's limits. If you happen to own a Zaskar the first thing I would do is buy a new front tire. They really want to keep the weight down on this bike but if you plan on riding anything steep, slippery, or sandy you will greatly increase your safety and stability with new front rubber. My choice was a Maxis High Roller II 29x2.30. Once I had it my speeds increased and I out-rode the rest of the bike. What about the rear tire? I didn't feel it was necessary because all the control comes from the front. When I converted this bike to commuting I kept the aggressive front tread because my commute takes me through some dirt and I wanted to continue trail riding. Trail riding an ebike is a whole other story!

    There are a few other things about the bike that need to be addressed.
    1) 160mm disc brakes are insufficient. Some bike manufacturers include larger rotors on L/XL frames. I wish GT would adopt that policy. 180mm should be considered minimum size for safety reasons. At my size I'm going to 200mm.
    2) The wheels should probably be upgraded. I've broken one spoke already. Now I carry spares. Also, the hub bearings are open to the elements. This is something that I wish I knew to avoid. Get sealed bearings so you don't have to worry about them. Upgrading wheels is probably in my future.
    3) Suspension in the rear or on the seat post would be nice for comfort. Each day is 2 hrs in the saddle for me so I need that.

    I read someone else's post that they only build on downhill bikes. I thought that sounded like overkill, but it would solve all of the things I've mentioned. My opinion is based on being a heavy rider that clocks a lot of miles with some pretty steep hills. This bike should work fine for someone who is lighter and has an easy flat commute.

    So what does work about this bike? Well, how about everything else. All the other components are just fine and the frame seems solid. I think some would say that I am overtaxing the frame but so far I'd say it passes. I've ridden chunky rock trails with my motor blazing and it kept on going. I think frame choice is the least concerning issue to be honest.

    Now about the BBSHD and Luna hardware. I think I chose the right setup for me. The motor gets me up everything. It's fast. In California we are limited to 28 mph. This is surprisingly fast enough for me. If you've ridden down a hill at 35 or 40 mph and felt good about it let me know! I think I need something motorcycle sized to feel comfortable above 35 mph. But there are situations where it is good to have the thumb throttle and be able to open up every last watt you got. I usually ride in PAS level 1. But if I need to get around a car or put myself into a safer location I have all the juice under my thumb. It also helps keep drivers from getting annoyed at me when there are no bike lanes. I can quickly get up to their speed and out of their way. The brake sensors are nice to have to get me stopped and to meet legal requirements. The gearsensor is very convenient for smooth shifting. I recommend it for anyone who thinks they might want one. The Luna color display is very nice. I am hoping that they release a new one in the future that is capable of USB 2.0. I have accessories that need 2 amps of USB power.

    The battery I chose was the 52v Pansonic 11.5ah Dolphin. I routinely get over 34 miles on a charge on a 11.5ah battery! But I am riding for exercise. I know not everyone rides that way. I have a shower at the office and I am definitely sweating when I get to work. I have attached a few pics of my battery charge and mileage with a chart of a typical commute. This should give some people an idea of what it is like with "athletic peddling". Like I said, I am usually in PAS level 1 and it just flattens out the hills for me. I average between 20 mph uphill and 30 mph flat. Stoplights are what keeps my average down at 19 mph. If I don't peddle I'm guessing my range would be about 25-30 miles.

    One last note about chains if you are also on a 10 speed cassette. I had some initial problems with my chain but for my second chain I bought a KMC X10-93 10 Speed Chain and I always carry extra MissingLinks. I kept breaking MissingLinks until I discovered a few things:

    1) The product says "KMC Missing Link 10R (reusable)". Hogwash. Do not reuse these links. I would open and close the connector to take my chain off but each time you do this you risk damaging the razor thin locking mechanism. It's really not worth the risk. Also, check the manual. "Caution: Always use a new MissingLink when fitting a new chain. Failure to shorten the chain properly or to lock it exactly into place may cause damage to the chain and eventually total chain failure, material damage or the rider to fall o his bicycle resulting in injury." It also states "Always check Missing Link. Suggest to replace a new Missing Link when it is worn or after locking and unlocking 3 times." That doesn't really sound reusable to me. So just don't risk it.

    2) It isn't in the manual but ALWAYS lubricate both pins when assembling a MissingLink. I was still breaking brand new links until I discovered this. Factory new chains come with very good wax lubricant on the chain. MissingLinks do not. They come unlubricated. So if you assemble your chain and then do what we all do, spin the chain around and squirt lube all over it, there's a good chance you missed a the link and you will quickly wear out those razor thin locking tabs. Once they widen out you are bound to pop one open.

    Now that I have this all figured out I have been on the same chain and link for months and I have no issues.

    Good luck everyone and have fun out there!
    Attached Files

    I realize this post if a year and a half old, but I wanted to acknowledge that it was a big help and one of many that I reviewed before spec’ing out my commuter bike. This commute is very similar to mine in distance, elevation changes, and riding style. I get similar battery performance although I spec’d a larger capacity battery since I wanted to charge only to 80-90%. Yes, the photo was intentional. Thank you for documenting your build and the insights. I've been riding for almost a year now and really enjoy my commute.
    Attached Files


    • mrmatt
      mrmatt commented
      Editing a comment
      Ha, great photo choice! Thanks for the shout out. FYI, I have 2200 miles on this bike now and I'm on to bike build #2.

    Nice. I have about 1200 miles so far. Besides fenders, I don't know of anything else that will make this a better commuting machine for me. What improvements are you planning for bike 2.0?