Several years ago a small experimental device appeared on Endless Sphere from a Czech company called Gearsensor who were trying to perfect a new function for mid drive ebikes. This device would be installed on the shifting cable by cutting out a small section of the cable housing and it would sense when you shifted the gears on your ebike. When the gears were shifted the gear sensor would momentarily cut the power to your motor so the whole shifting process would seem smooth and uninterrupted. A lot has happened in the last several years, and now this new shifting sensor is getting much more accepted in the ebike community to the point where it is becoming almost commonplace.
There are so many opinions out there about this Gear Sensor. Is it a must have? Will it integrate seamlessly with my BBSHD\BBS02? Where should I buy it? I’ll attempt to answer most of these questions in this article.
My first exposure to the Gear Sensor was while testing the E-Rad branded BBS02 drive system last year in this article. My feelings about the gear sensor have not really changed from that article, I still think that it should be bundled with the BBS02 from the get-go. There is a lot of reasons this hasn’t happened, but those are kind of boring are outside the scope of this article. What has happened is that Bafang has finally woken up and smelled the coffee and is not including a dedicated gear sensor plug on the BBSHD controllers when drive units are ordered with that plug installed. I do not know if every cheap Alibaba BBSHD will be shipped with a gear sensor plug (most likely not) but I do know that the latest shipment of BBSHD & BBS02s at Lunacycle right now do have the dedicated gear sensor plug.
The gear sensor on an E-Rad with a cable that is just a little too short for its own good
Do I need a gear sensor at all?
When it comes to shifting under load and understanding the problems it creates with the drive system you have to think about where all the tension is on your drive system. Almost all the tension is on the top of the chain. This is why when you have a front derailleur and you shift under load on the front ring that is when the links in the chain will generally break apart. With a rear derailleur, you can shift under load and it doesn’t make much difference since the bottom chain line is not under tension. Shifting into a higher gear will not generally create much of a problem, but sometimes shifting into a lower gear will. The gear sensor senses when you are shifting and what direction you are shifting in and it cuts the power for an appropriate period of time for the shift to complete.
Almost all shifting problems I’ve ever had with the BBSxx have come from bent derailleur hangers or misaligned derailleurs. In my experience, a properly tuned and straight derailleur should not break chains even when shifting under load. Many people who use the BBSxx just tap their ebrakes when shifting under PAS which essentially does the exact same thing as the gearsensor.
What about with my fancy expensive IGH?
For an IGH it’s a totally different story. Many 3 speed IGHs like the Nexus 3 and the Sturmey Archer 3 speed hub seem to not complain too much when shifted under load. I have beaten the crap out of my 3 speed IGH’s and shifted them constantly under load without any issues. Other IGH like many more delicate 7 or 8 speed IGHs will absolutely self-destruct if they are shifted under the full 1500W load of a BBSHD, so a gear sensor would be absolutely mandatory in that instance.
If you’re having chain problems … I feel bad for you son, I got 99 problems, but …
Must I have the dedicated Higo controller plug to use a gear sensor?
This is one area where people seem to get really confused. You can hook up a gear sensor to either ebrake cable hookup on the BBS02 or BBSHD and it will work just fine. The delay is a little longer, but most people will probably not even really notice the difference. Any gear sensor bought with a Higo style plug will work with ANY BBS02 or BBSHD on the market.
Are there different gear sensors for IGH and Derailers?
Yes, figure out what setup you’re using and get the right gear sensor for your setup. If you are using a CVT like a Nuvinci N330, N360, N380 or N171 or if you are using a Roloff IGH then you will want the gear sensor for standard derailleurs (not the IGH gear sensor). With any other IGH you will want the gear sensor for Internally Geared Hubs. I know, it’s really confusing, blame someone else, I just work here.
Where do I buy a gear sensor?
Until very recently the only place stateside you could buy a gear sensor stateside was from Lectric Cycles for $75 + $15 shipping here. Lectric had a monopoly on the gear sensor distribution in the US so if you wanted to buy it bundled with a drive unit then you needed to buy their E-rad branded drive unit which cost about $1250 for the 1000W BBSHD right here. If you wanted a gear sensor included with a BBS02 for a 100mm fat bike then you would need to spend $1200 for a 750W BBS02 right here. Although both drive units shipped with a gear sensor, chainring adapter, and a Raceface chainring included the pricing is still much more than most ebike builders really want to pay (cause you’re all so damn cheap). As of about a month ago you could order a gear sensor from Paul at em3ev in China as a $50 add-on to a BBSHD, but I can’t find a listing for the individual gear sensor anywhere on his website.
Gear Sensor. Meh. I was pretty excited when I first tried it, but I just never use it anymore. Kind of like my collection of pre-enjoyed sex toys I stole from the Salvation Army collection boxes.
As of right now Luna Cycles has gear sensors in stock which they are selling here for $50 +$5 for shipping. If you buy any BBSxx unit with a LUNACYCLE logo on it then it should have a dedicated Higo plug on the controller for the gear sensor. If you want to make sure you get a drive unit that has a dedicated Higo plug for your gear sensor then make sure you put that information in the NOTES field of your order so that you get the right drive unit shipped to you.
Are all gear sensors the same?
This gear sensor you buy from Lunacycles, Lectric and Paul are all exactly the same product. There are no differences between them. While there are differences between the IGH and the derailleur versions of gear sensor, between different vendors they are exactly the same product. For info on gear sensor dealers in your country, click here.
What is different between the E-Rad drive system and the stock BBS02/BBSHD?
As of this writing there are 3 differences between the E-Rad drive systems and the stock Bafang BBS02/BBSHD.
- The logo on the side of the drive unit says E-Rad and not Bafang or something else (If you order a thousand of them they’ll print whatever you want on the side, I’m ordering ones that say “FUCK YOU BIKE THIEF” on them as soon as I raise $500,000 on Kickstarter to place an order with Bafang.)
- As of about a month ago, all BBSxx drive units produced by Bafang are going to ship with the extra gear sensor Higo plug exactly identical to what Lectric is selling. Many of the drives that are currently for sale on Alibaba or ebay will not have it. When it doubt ask your vendor before you buy. If they don’t know what you’re talking about then just buy from someone else who knows what the hell they are selling.
- The programming on the E-rad is slightly different from the stock Bafang programming. I would not say the programming is that much better, just different. Instructions on programming your BBSxx unit as well as Lectric’s firmware settings click here. For programming that doesn’t suck just use ‘Karl’s Special Sauce’. It will void your warranty, but it’s well worth it.
Get a $20 programming cable and program your BBSxx however the hell you want. The stock Bafang programming is totally unusable.
That’s really it, there are no other differences between the E-rad drive system and any other BBSxx drive unit you buy anywhere else. That means you can get a BBSHD from Lunacycles for $699 here and add a gear sensor for $49 and a Luna Eclipse 42T chainring for $99 and you’re still $400 ahead of the E-rad one and the only difference is the controller programming and the logo. Take that $400 you save and buy a 52v shark pack for $435 here and you’re ready to roll. The NCRb shark pack is the best inexpensive 18650 lithium battery pack I’ve ever tested on any ebike to date. If you’re using a BBS02 then get the NCRb cells and if you’re kicking it with the BBSHD then I strongly suggest the PF cells. 52v batteries are the only way to fly on the BBSxx units, and Lectric will not warranty any of their drive units that are used with a 52v battery. Luckily, Lunacycle will.
In the end, the choice is yours of whether to go with the gear sensor. In all honestly, I could take it or leave it, $55 buys a lot of drugs beans and rice. My two E-Rad branded BBS02 drive units are my least used ebikes in my garage, and I seem to get by just fine without a gear sensor on my other 10 ebikes. If you’re an ebike fanatic and you don’t mind springing for the extra $50 it might be worthwhile for you. I’ve just gotten in the habit of not pedaling for two seconds when I want to shift, then shifting and then starting to pedal again. As the power slowly ramps back up your shift will be silky smooth and chain-crunching free.
It’s not that hard to do. You’ll be $55 richer for it, but hey it’s only money right?
Ride on.
ElectricBike-Blog.com 
Hello sir.
Nice article as always. Just one note, Czechoslovakia split like 25 years ago.
Anyway, I am working on a Power monitor for bafangs. Hw is almost done as proto, now need to code iPhone app. Can send you some pictures, if you interested.
DaDo from Slovakia 😉
>
LikeLike
Yup my bad. Typical American attitude with my head in the ground.
I don’t own an iphone, but sure send me pictures. Thanks for reading.
Karl
LikeLike
Great article as always, Karl. This is much needed info to clear up a lot of common questions. The BBS02 went through a lot of upgrades to fix various issues, and in its current form I still recommend it as the best 1000W mid drive. For more power, you can either run the BBS02 hot, or upgrade to the BBSHD @ a cool-running 1500W. I just got mine, and the gear-shift power-interrupt was the only remaining question. I am certain it accesses the E-brake power cutoff circuit, but I’ll have to dig into that (someday soon) to be sure.
LikeLike
Karl, can you let us know how to tell the two different types of gear sensor apart? Is there a p/n or visual indication if I have an IGH or deraileur version? I asked Gearsensor themselves directly, but got no response.
LikeLike
ooops, I posted my question before checking my mail. Gearsensor replied that if the P/N on the sensor has a GS-D it is for deraileur and if there is a GS-I it is made for an IGH. Now I need to go and check mine!
LikeLiked by 1 person
The most recent crop of ‘affordable’ production bikes are mid-drives around $2k. They are not putting shift sensors on these, at least the Shimano STEPS, and the Currie. I think it hurts the ebike shops because the hard shifts are not a selling point on a test ride.
It’s curious that for 50 bucks you can get a shift sensor on a DIY bike. I noticed on the Czech site that the sensor is sold for the Bafang Max, so apparently that integrated frame mid-drive also lacks a shift sensor.
If you look at the grand sweep of history (I can be really pretentious) mid-drive was supposed to be what a low power ebike needed, to climb hills. But high power DIY e bikes with mid-drives are the standard in the US. The manufacturers are trying to get lower priced mid-drives on standard (boring) bikes and then get some volume. Accell is pushing this, and they pushed the wattage limits and wattage labels in California.
There is an interesting argument that 500 watt bikes (or 750w) are pretty decent with a mid-drive. Not for sand and snow, but for commuting or exercise or simple joy. The BBS02 sort of distorted everything. Suddenly there were high power mid-drives, really only legal in the US. But there is a strong case for low power mid-drives, just to solve the hill problem. I think they will include shift sensors, for marketing. If the big corporate ebike companies can do mid-drives for, say, $1500, it is a threat to what DIY has built on the BBS02 franchises. Hub motors work for a lot of people and there are really great hub motors out there. But DIY in the US seemed to become a huge force in the US on the strength of the BBS02.
Branding the BBS02 shows how dominant it became in a couple of years. That can’t last.
LikeLike
I don’t need a shift sensor. I just plan ahead and shift into the gear I need to be in before I need it. More wiring dangling off the frame is ugly and just collects mud. Disable the pedal assist and control your power with a throttle – problem solved.
I find the weak point on the BBS02 system is the chain and cluster. They start to wear and skip after only about 600 km. Pedalling up steep hills with the motor maxed out stretches the chain, which then ruins the cluster. I’m switching from a 9 speed to a 7 speed cluster with a beefier chain. Hopefully that will last a bit longer than 2 weeks.
LikeLike
I think that’s more a comment on weakness in your bike or your maintenance, not any weakness in the BBS02, that cogs and chains wear out. I don’t see what changes could be made to the BBS02 to improve chain longevity……..
LikeLike
Perfection be achieved without gear shift sensor. Back pedal a fraction pre-shift cuts power.
Works on BBS02, works on Bosch Performance Line, works on BBSHD.
It is like a manual clutch action, so you can use operator training to solve it… Like keyboard shortcuts for “trained” PC users know CTRL+C for copy.
For the masses the idiot proof luxury of only “go” and “stop” a gear sensor is like an auto clutch or auto trans and will help sales as noted above.
I was given the tip of backpedal on E.S. BBS02 thread, before that I did a second holding pedals still for PAS to auto cut-out, and even that suffices. Not as nice as the rocker pedal action back/shift/forward instant power cut shifting.
Not everyone is born with mechanical sympathy OCD but we can infect the others 😉
LikeLike
I have noticed that the motor immediately cuts out if you backpedal a slight amount. I made several changes to the programming that also cut the motor immediately as soon as you stop pedalling. Check out Karl’s special sauce on the programming page.
LikeLike
Sensor killer?
LikeLike
i want to get in on some of that branding stuff and call my drives the luna cycle drives…the same damn thing but 100 dollars cheaper than the bafangs from china….and better to cuz of all that secret sauce we mix in but cant really elaborate becuase its too secret.
LikeLiked by 1 person
I simply give a slight pull on the brake like I was using a clutch. I don’t have to stop pedaling at all and it shifts smoothly.
LikeLike
All the above comments about workarounds for the Gearsensor are correct, but when training a novice ebiker it is nice to have one less thing to worry about. Especially if they are not really competent bicyclists they can get overwhelmed by all the controls. Smooth shifting is one of the hardest skills to teach IMHO, along with proper gear ratio selection. Adding a motor does not help one bit either…….
LikeLike
Coincidentally just installed gearsensors on both of my BBSHD bikes yesterday. What a difference, works nearly seamlessly. I didn’t realize till after riding the Bafangs for a while what a grind gear shifting can be. Pulling brake levers, or stopping pedaling just to shift is slow and inconvenient.
Gearsensors should really be mandatory to get the full enjoyment and performance out of a mid-drive. My bikes shift much faster and smoother under power now. Don’t have to lay off the throttle, or stop pedaling at all. Just goes.
LikeLike
Fully agree the experience of a gear shifter is awesome well worth the money in my opinion. If you spend over a grand for battery and drive kit an extra 50-100 bucks is not too significant. I also feel much better lending my bike to my girlfriend or friends knowing that they probably won’t explode drivetrain things.
LikeLike
I own one, haven’t gotten around to installing it yet. I was getting buyers remorse until I read your comments. Thanks for commenting!
LikeLike
I installed a gearsensor on my BBSHD and BBS02 and it makes a world of difference. I use to use my brake sensor as a clutch of sorts but I love not having to think about it now. So much better. Get one!!!!!!!!
LikeLike
So I’m wondering. Does it matter which direction you mount it?
Karl, you said up top:
“The gear sensor senses when you are shifting and what direction you are shifting in and it cuts the power for an appropriate period of time for the shift to complete.”
That would mean the direction the cable inside the sensor is moving would affect the pause duration of the motor. i.e. the direction the Gearsensor is mounted will affect its performance.
The eRad installation video agrees with you.
The manufacturer–not so much.
installation manual says:
“Start pushing the inner cable into the plastic housing from any of gearsensor sides to fit cable direction to the controller input.” (????)
And their website shows a bike with it “backwards”.
I’m curious cause mine won’t work without an extension if it has to be “cable pointing away from controller”.
LikeLike
It should work either way. I think. Send an email to gearsensor.com and let me know what the answer is. Pretty please.
LikeLike
That’s a great (obvious?) idea. Why didn’t I think of that?
They said:
Dear Phil,
you can choose the direction, both are possible.
Best regards / S pozdravem
Radim Mráz
gearsensor.com / Head of Sales, Co-owner
LikeLike
That’s why I get the big bucks
LikeLike
Warning — Potentially stupid newbee question…
My BBS02 has a gear sensor cable coming out of it. What do you do with the cable if you don’t want to run a gear sensor? Cut it off? Zip tie it to a tube and forget about it?
LikeLike
You can do either one just make sure that there’s no power when you cut the cable off. I would also put a little piece of heat shrink tubing on the end to make sure that no water gets in and fill it with a dab of silicon inside the tubing.
LikeLike
I have shift sensors on both my BBSHD and my wifes BBS02 and while I don’t actually use my shift sensor much since I prefer to use my brake sensor in the same way you would use a clutch on a motorcycle but it’s nice having it there. As for my wife or anyone taking my e-bike for a test ride it’s a very nice feature to have and worth every cent of $50.
LikeLike
Great article, Thank you for confirming what I thought about the “custom” printed cases.
LikeLike
Karl, which gear sensor for a Strumey-Archer 3spd IGH 8-9spd Cassette unit; the CS-RK3? The reason I ask is that this particular 3spd IGH uses a standard front derailleur 3spd control. It will not work with a Strumey-Archer 3spd IGH control. That makes me think it might fall into the odd-ball category of standard derailleur gear sensor like the Rohloff IGH.
Your thoughts and experience are greatly appreciated!
LikeLike
I don’t know. Send an email directly to info@gearsensor.com and post the answer back here so we all know the right answer.
LikeLike
Thanks for the direct contact. Gear Sensor got right back to me:
“For this application we do recommend to use GS-D model (for derailleur).”
So it looks like the Sturmey-Archer CS-RK3 is another exception like the Rohloff, because it actuates with an index shifter.
PS: Karl, if you have the opportunity to test out the CS-RK3 at some point and add it to your wonderful IGH review article, please do. It’s not clear to me if the internals are the same as the other SA 3spd IGH’s that don’t have a cassette. Keep up the good work!
LikeLike
Dear All,
I see that you have discussed here usage of GS-D and GS-I models for different shifting systems.
In the last months we have worked very hard to prepare a new model for BBS motors that will be universal for all kind of shifting systems. This we have done by changing the parameters in the gearsensor in order to optimize the feeling from gearsensor function in combination with different shifting systems.
Soon, new model called GS will enter the market. This new model is universal, for all kind of shifting systems. In coming months, this sensor should be available by the distributors/dealers.
Radim, gearsensor.com
LikeLike
Hey Karl,
I have about 1000mi on my BBSHD, I decided against the gear sensor on my build, but now I am revisiting the idea, here’s why…(would be interested in any feedback from folks here)
I am using the Tektro e-brakes sold by Matt at Empowered Cycles. Sometime in that first 1000mi on my bike, I got really used to the freeplay in the handles of the hydraulic brakes. I could easily use them like a clutch, there was enough freeplay that I could pull the handle without any braking actually occurring, but it would cut out the motor so I could shift. Basically I end up just tapping and holding the ebrake pretty much at the same time as shifting, then letting off the ebrake just barely after — I found I could shift very quickly this way even when on a hill. This was my first ebike, so I didn’t start riding it like this initially — when I finally figured out how to ride it like this, I guess I had already worn the brakes down quite a bit.
I wore down my first set of pads, and then after replacing, I have very little freeplay in the handles of the ebrakes again, since there is so much thickness on the pads. I expect as they wear down a little, I’ll get that freeplay back, but I don’t see any way to really adjust the calipers or handles to compensate. Essentially, if I try to do what I used to be able to do, in order to cut the motor out I have to squeeze hard enough that I am applying significant braking (which is not what I want of course) — presumably because the built-in ebrake sensors need more distance apart before they switch. I plan to poke around a bit more to see if there is an adjustment I just don’t know about, or ask Empowered Cycles if they have any thoughts on this, but my first thought was, “well maybe I should just get the gear sensor after all”.
I think the only other real motivation for going with a gear sensor (assuming they actually work well) would be easily shifting with one hand. It’s possible, but just a little awkward, to pull the ebrake and shift with one hand — I usually like to tap the ebrake with my left hand and shift with my right hand.
-Chris
LikeLike
Hmm, Seems like I pretty complicated system. I’ve used ebrakes to cut the power to shift and it works well. You can loosen the cable a bit if the pads are new and there is no play. Honestly, most of the time if I want to shift I just stop pedaling for a second till the motor cuts out then shift and start pedaling again. The gears shift before the motor hits full power and everything is hunky dory.
LikeLike
I added ebrake reed switches/magnets and the shifter sensor both to my ebike.
My intention was to let ebike virgins ride my bike. I need it to be amateur proof as much as possible. Dozens of people have ridden my bike and a few went on to buy/build an ebike. More bikes on the road here is a good thing.
Also, it has been nice to push the thumb throttle about 50% and just click through the gears without drama as I build speed on a straight bit of asphalt.
LikeLike