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    Gear shift sensor... Needed?

    I'm planning a build and wondering about the gear change sensor. Some say that it's not needed as long as you're mindful of not shifting when the chain is loaded. As a long time bike rider, I'm mindful of that and figure I don't need the added complication. In the other hand I figure it helps the drivetrain longevity to have the insurance. I'm a long time manual car driver and have removed devices from cars that were meant to "help" be use a clutch right, but which actually made it harder on me and the clutch.

    After shift sensors strongly recommended it just protection against thoughtless riding and shifting?

    #2
    In my opinion... there is(or SHOULD be) automatic gear shift sensor already installed. It's called your brain. I have no gear shift sensors, Ebrakes, PAS, Torque sensor,or displays on any of my bikes. I use my brain. It (usually) dosn't break down.

    Comment


      #3
      I like the shift sensor. Without it I have to pedal backward ten degrees to cut off the motor shift then pedal again. It brakes my rhythm. I have a dropped handle bar road bike and clip in. I want as natural a bicycle feel as I can get putting out 1500 watts of power with 200 watt legs.

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        #4
        I find it very useful and it's not complicated at all - it really couldn't be simpler.... I see zero downside...

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          #5
          i had both types. there was more of a delay in the cut off than i was expecting so of the two options i would go without.

          Comment


          • joebreeze
            joebreeze commented
            Editing a comment
            Well said !. The delay is too long . Not everyone wants to 'hotrod' and void the warranty by altering the programming.
            Also $50 for a little plastic wheel with an on/off switch is daylight robbery . Also for $50 i'd expect it to be waterproof and rain/dirt biking ready.
            Mine came with so much silicone inside the shell , I couldn't get my cable through and I had to disassemble it ?! , and pull out all the silicone , which is not what consumers should have to do.
            Last edited by joebreeze; 06-30-2019, 07:54 PM.

          #6
          Assembled my BBSHD on a KHS 1000 Fat Bike and it worked great but I had to be VERY patient shifting due to the overrun of the motor. The overrun was really quite distracting from an otherwise great build. Installed the Gear Shift Senor and now shifting is VERY natural feeling without any undue stress on the drivetrain.

          Have no need for the brake cutoff but the Gear Shifter Senor is a very good option in my opinion.

          Comment


            #7
            I believe you can dial the over run out. I use the gear sensor on all the bikes. I don’t have a brake sensor on all the bikes because it was a real pain trying to install on the brake levers.

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              #8
              I have stock programming on a BBSHD. Full suspension Cannondale, SRAM x5.

              No gear sensor - I don't think it's needed. In PAS 1 or 2, I shift under power all the time. Works fine.

              I have a good chainline, I think that makes a big difference. A little mechanical sympathy helps too.

              All that said, if I was building up a new bike and doing the gear sensor was easy and inexpensive, I'd think I would do it.

              Comment


              • jimz
                jimz commented
                Editing a comment
                I agree with SRG, level 1 or 2 assist, my Trek 7.2 fx with a BBSHD shifts just fine. In higher levels, just pause pedaling and shift normally. I haven't tried a gear sensor to see how it would improve things, but everything works pretty darn well without it so I don't plan on adding it.

              • AZguy
                AZguy commented
                Editing a comment
                As mentioned, I can't think of any reason not to put them in and will continue to do so. They are inexpensive, reliable (5000mi no maintenance or issues) and keep shifting "bicycle-like" - i.e. no pausing pedaling (or reverse), touching brake lever, or whatever to interrupt motor power during the shift. While it may be debatable that there's a significant benefit at low powers to interrupting the motor. it can't possibly be worse than not limiting it and I don't think it's debatable there's a benefit at higher powers.

                Bottom line - zero downside so why not?

              #9
              Being a lifelong cyclist my thinking was right along the lines of marcva . One less thing to break down if I leave it off, and I know how to shift mindfully, thank you very much. For a 1500w BBSHD, regardless of chainline, you had better not shift under PAS or throttle power. That stress adds up and will eventually end badly. and that means a chain on the ground, maybe some broken cog teeth (or split cogs) and you walking unless you have a chainbreaker and spare links at the very least.

              So I adjusted my BBSHD programming so the motor cuts off as soon as I cut throttle or PAS power. I develop a technique of pedal. Stop. click-shift. pedal. Works fine.

              For my second BBSHD build, I had this left over gear sensor and I figured what the hell lets put it on during the build and see if I like it. So I did. And I do. It cuts motor power back just enough to keep me happy about drivetrain wear, but not so much I feel like I am losing rhythm.

              I wrapped it in self-sealing silicone tape, by the way, to keep grit out of it over the long term. All it is inside is a little wheel turning via friction from the cable. Sensor senses any turning and shuts the motor off for a moment.

              Its a tool in your arsenal. take advantage of it. You don't have to use it all the time, either. If you don't like technology what are you doing with a motor in the first place? :-D

              Comment


                #10
                To address the point about "one less thing to break"... if they fail it's usually just the wheel inside not turning so they nearly always fail-safe such that they simply stop gear sensing but don't interfere outside of that. In the [unheard of?] case where it somehow was stuck always in cutout then just unplug it, it's just like a brake sensor. BTW - When it fails due to the wheel not turning it is an incredibly easy "failure" to address, just pull the two screws closing the housing, clean the wheel and cable, maybe rough the cable at the wheel with emery cloth and a tiny drop of lube on the wheel pivot. Mine stopped sensing early in its life and with these newer cables that are super slick the roughing it up is all it likely needed and cleaning and very lightly lubing the bearing didn't hurt... Regardless, thousands of miles with no trouble from the sensor since that initial issue...

                Comment


                • MoneyPit
                  MoneyPit commented
                  Editing a comment
                  Interesting. I didn't bother greasing my shifter cable as it was already so smooth to the touch I figured lube might attract more crud than it works around. Thx for sharing I'll keep this in mind down the road.

                • AZguy
                  AZguy commented
                  Editing a comment
                  Yeah - the newer ones are coated with some hard teflon-slick treatment so you definitely don't need lube!

                #11
                Been reading this thread with interest. On my commute I ride over a section of corrigations. The fine vibrations cut the motor out on my BBSHD equiped bikes, I’d been putting it down to poor battery connections, then when I squared that away, some internal connection in the BBSHD. They’re made in China and didn’t cost a great deal so suck it up fella. I couldn’t figure out how others rode BBSHDs on rough single tracks without issues though. Then a mate pointed out that it’s the gear sensor and it all seems obvious now. I was thinking of simply disconnecting it but other than a mild irritation during the corrigation section, they’re really no issue.
                So after all that I was considering if a simple in line on/ off switch could assist. My default setting will be to simply leave it on though.

                Comment


                • MoneyPit
                  MoneyPit commented
                  Editing a comment
                  Yeah if the cable is moving that should mean your derailleur is shifting. Maybe you are at the end of travel and you allowed your cable to slacken? That slack is the problem? BTW Wuxing sells a HBIGO-plugged green horn button that works perfectly as a manual power cutoff. I use that on my first BBSHD - the one with no gear sensor - when I want to shift clear across the cluster or some similar extended shifting behavior. A cheap and easy crutch.

                • Hard Tail
                  Hard Tail commented
                  Editing a comment
                  Just when I thought I had it sorted...thanks AZ and $pit. OK. The cable adjustment must be reasonable because the gear shift is functioning well. I will try simply disconnecting the sensor on Thursday’s commute and see how it’s goes. My other reservation is the quality of my sensor but it looks just the same as the Luna product . Should have my answer

                • MoneyPit
                  MoneyPit commented
                  Editing a comment
                  I haven't broken a chain yet but I have heard enough stories like the above to know what I need to do. In my case, I have a spare x9e chain and a pair of spare master links... and a little set of master link pliers I got off of EBay. When I have some time, I need to check my chain size and resize this spare chain. Right now I have a small chainbreaker - broken down into pieces so it fits in my tool kit - and I'd have to resize on the side of the road, or use low gears home. Makes more sense to pre-size methinks. Just need to get off my ass and do it before I need to do it roadside.

                #12
                As I said above, PAS 1 or 2, shifting under power works fine for me - for the last 1700 miles. No broken chain, still running the same one I started with.

                Comment


                  #13
                  Originally posted by LordBinks View Post
                  i had both types. there was more of a delay in the cut off than i was expecting so of the two options i would go without.
                  This is just what I found with a gear sensor on a BBS02B, too much delay after the shift and late cutoff during the shift too at times. I now use the quick backpedal, shift and go method. It works great for the wide gear spaced IGH hubs on both of my rides; one has a 33% gear gapped 3-speed and the other a 25% gear gapped 5-speed.
                  MOVING BACK TO PEDAL...
                  2020 Banshee Paradox V3 1x11 (pedal)
                  2018 Soma Wolverine 3spd IGH Belt Drive (pedal)

                  Comment


                    #14
                    I've been riding my BBS02B bike over 4,000 miles now, mostly commuting, with no gear sensor. What I do is just tug the left brake handle slightly when shifting. It has become perfectly natural now, just muscle memory, so much so that I sometimes do it on my non-assisted bikes. It almost feels like using a motorcycle clutch, even though you normally only use that when starting out from a stop. But I just ride along, tug left brake slightly while shifting with right hand. The motor cuts instantly when the brake handle is moved just a small amount (before brake pads actually touch), and shifting can be done with minimal issues.

                    But still my bike tends to eat through 8 speed chains. In 4,000 miles I've already stretched out 2 chains. I need to buy another one this week, actually.

                    Comment


                      #15
                      2000 miles for a chain on a mid drive is not bad. If you haven't tried one already, consider a more sturdy chain. KMC makes mid drive chains. Their 'e' line.

                      Comment


                      • joebreeze
                        joebreeze commented
                        Editing a comment
                        I can do without the costly sensor which on my FS MTB used to cut the motor on bumps.
                        I was already to take the sensor off and sell it back to someone , when that day a Husky chewed through the cable on my parked bike.
                        Last edited by joebreeze; 06-17-2019, 07:30 PM.

                      • AZguy
                        AZguy commented
                        Editing a comment
                        I'd suggest if it's cutting out on bumps, it wasn't installed properly - the cable shouldn't move just because of rough stuff. I spend plenty of time on super rough stuff. In 5000mi the only problem I had with the gear sensor is that not long after install it stopped working which was very noticeable and undesirable with nasty noises coming from shifts unless I interrupted power by activating a brake sensor or interrupting pedaling... and that was solved quickly by just roughing up the cable where it contacts the sensor wheel in the unit - a <5min job.... no issues whatsoever in the 5000mi since...

                        Costly? Mine was $40... cheap if you ask me...

                        YMMV

                      • joebreeze
                        joebreeze commented
                        Editing a comment
                        It was installed correctly . Also the last thing I need is the motor cutting on steep rocky inclines when shifting down

                        EMYC
                        Last edited by joebreeze; 06-30-2019, 08:18 PM.
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