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Surly Ogre 29er BBSHD build

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    Surly Ogre 29er BBSHD build

    Hey internet, I just completed something new and cool and I thought I'd share.


    Surly Ogre 29er size medium
    BBSHD 68-73mm
    46T chainring
    860c display
    Universal Thumb Throttle
    gear sensor
    Direwolf 52v battery

    Most everything went very smoothly. A couple of hiccups:

    existing stock chain was too short for the 46t chainring. Had to order this on Amazon which came same day:

    My limited engineering skills could not get the hydraulic brake cutoff sensor to work on the existing Tektro brake levers. So I am riding without the sensor, which is not noticeable to me. I don't find them necessary (yet). Interested to hear if anyone has comments on this.

    I have always thought that would be a good bike to convert. Seems like a rugged do all but hardcore offroad bike. Good to know its not a big deal to do. Did you need any spacers? How much clearance do you have on the chainring?

    I like having both the gear and brake sensors. There are times when you biff a gear change and need to kill it or where that after run could get you in trouble. I could see if you are more of a mellow commuter or throttle only maybe it won't be that big of a deal.

    For the getting the hydraulic brake sensors to work you just have to experiment. Some kind of spring clamps or even just tape can help you hold things in place for testing. I have been very happy with hot glue to keep things in place once I figure out where I want stuff. Hot glue is nice because its easy to remove if needed.

    If the brake levers are the same top and bottom its easier to experiment on the top then move to the bottom once you figure out the layout. No one seem to note it but the orientation of the magnet makes a difference so put some sort of mark on so you can keep track of how you have it oriented so you can easily find the sweet spot again. I'm not taking about just horizontal or vertical, rotating it on top of that also makes a difference. There are orientations where its really mushy and takes a ton of movement to trigger and another where its very sharp and just a mm of movement will trigger it.
    If the 860 is like the 850 it seems to take a long time to actually display the ! sign so maybe if you got a stand tape the throttle on to get a quicker indicator that its working?


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      You are correct, it is plenty rugged enough for what I wanted it for: commuting on roads and bike paths. And the 29 inch wheels means it has plenty of ground clearance under the motor. I have no plans to take it off-road.

      It required zero spacers. It fit almost perfectly. I've attached a couple pictures for viewing pleasure.

      You can see the motor body does sit snug against the chainstay there but doesn't seem to affect anything. Should I be concerned about that?


      • 73Eldo
        73Eldo commented
        Editing a comment
        I would like to be able to slide a sheet of paper between the gear case and frame just so I knew it wasn't going to stress anything.

        The Lekkie 42 would for sure work since its only like 1mm in from where that stock one is. My eyeball thinks the Eclipse may work too which is 6mm further in than what you have but being a little smaller gets you into that curve. I think I would order some chain ring spacers just in case you needed to loose a mm or 2 but that would really tuck that think in for an even better chain line than you have now. Too bad their blue isn't quite like that one.

      Also, It does have a gear sensor which I appreciate. And thanks for tips on brake sensor!


        While I like the brake sensors they are fussy at best on hydraulic brakes.. Even once mounted as the brake pads wear mine would lose adjustment so I'd redo them and then later when putting on new pads they'd need to be remounted again. And even with VIRB tape they'd still get knocked off every now and then and they really are a pain to mount and adjust.

        I also didn't like having them on both front and rear since there are times when I would need to go at very slow speeds when not on the seat and not pedaling (parking the bike in cramped spots, especially if up a slight incline) and wanted to drag a brake while throttling a tiny bit so I ended up removing the front brake sensor - my front brake is powerful enough to slow the bike even if power is applied, I have the throttle on the same side as the front brake so unlikely to use both and I never keep pedaling when I panic stop anyway so not really a "safety issue"...

        After so many times fussing with them I gave up. I'd rather have the front one and no rear one but they're just too much of a pain for me for now... maybe one day I'll get around to replacing just the front...


          Interesting. I didn't know there were any issues with mounting the brake sensors. Since they are not coming with my build from cycle monkey, I'll have to add them myself. What is the exact issue with mounting the brake sensors? These will be on magura hydraulic disc brakes and a Jones H bar.


            For me there are two very different issues

            The magnet and sensor have to be at just the right distance from each other and there is very little tolerance to the gap. The only place to put them is close to the pivot so the amount things mover there is very small and the placement to ensure that it will sense when you pull the brake and not either sense brake pull all the time or never is a non-trivial effort by trial and error. I also found that when I replaced the pads it would no longer sense so it all had to be redone.

            The other is that the surfaces aren't typically flat - more complex compound curves so getting the sensor and magnet to adhere well is a challenge with double sided tape. I used VHB tape which is considered permanent but I still managed to knock a sensor off. People have used epoxy but dang, if for some reason you need to readjust or a sensor gets damaged you're sort of stuffed. Hot glue isn't any stronger than regular double-sided foam in my exprerience.

            In the end I just don't think the bring much to the party in the first place. I've been running without them for quite a while now, thousands of miles and don't miss them a bit. I frankly don't really see much point in them at all. The *only* value I found is when slowing down they'd interrupt the PAS power from pedaling to downshift but that's just not a big enough deal to mess with them. If the brakes came with them already installed so two issues I mentioned were entirely non-issues I'm still not sure I'd bother hooking them up. I come from a moto background and when I gave it some thought - I sure as heck wouldn't want my throttle cut and clutch pulled every time I used the brakes - it really isn't different when you think about it...

            Gear sensor is another animal entirely and the once or twice it got gummed up and quit sensing *really* missed it and spent the five minutes to clean it out


              AZ, on the brake sensor(s), I had an interesting thing happen last week that appears to have changed my mind on a brake sensor. Riding my BBSHD MTB recently with my normal Bafang rear-brake-sensor-only on the left handlebar side ala dirt motor setup, I fell on a technical rock feature on our local trail. Lots of pointy rock, but I lucked out and only got a tiny scrape above my knee/shin guards. No real damage to the bike either, but I quickly noticed my brake sensor magnet had been completely knocked off. Well heck...I like the rear brake to have a kill function in certain scenarios, but I knew I could just unplug the sensor and continue to ride.

              Hmmm, as the ride continued I found I kind of liked just using both brakes without concern of the motor being interrupted. I was doing this before by just using the front brake in corners and such while still pedaling and laying off the rear brake. Kind of like still being on the gas a little as you ride the brakes and slip the clutch on a dirt motor in corners or obstacles.
              One thing different with my bike is that I have 4-piston brakes now...started on the original single piston brakes I had on there for years. I believe these 4-piston brakes provide enough power that even while riding in a decent power level, I can overcome cornering or approach speed with ease and not be as concerned about the rapid motor cutoff provided by the brake sensor. I'm a little surprised that the lack of the brake sensor hasn't been the issue I thought it might least with these brakes.

              One thing I'm missing at the moment is the ability to pull in the rear brake lever a little to insure that the motor is dead when yanking the bike out of a hole, brush, or just get back on the trail after an overshoot. Wresting the bike around or pushing over an obstacle when the pedals and throttle can still get bumped makes the brake sensor useful for that. I haven't given it much thought, but there may be a creative way to have a brake sensor engage when desired that doesn't involve the brake system. I'll look into that.

              Just did another ride this AM, and I think the jury is in. I can do without the brake sensor(s). My learning curve is getting shorter in how the PAS operates and my gear selection with PAS...PAS the way I have it currently programmed. I'm still sold on the shift sensor. When I get an Oh-XXXX moment in a technical spot, downshifting is definitely smoother with the millisecond motor shutoff. AZ, on the potential for dirt and such in the shift sensor, I noticed a few of those complaints and mounted it on the backside of the downtube in as protected a place as possible. Still, over time dust and debris can make their way in. Like your area, my riding terrain is almost always dry...and when it's not, I don't ride. As I've gotten older I hate riding in wet terrain, and I hate what it does to the equipment.


              • AZguy
                AZguy commented
                Editing a comment
                That's where I pretty much ended up!