Adding a Torque sensor

[RogerA]

Hi. I'm new to this forum, but was hoping for some advice on adding a kit to an existing bike.

I'm interested in a torque sensor kit and was intending to buy one of the Woosh rear hub TS kits, but they are out of stock and not expecting to get them back in again.

I've found a few sites where I can buy a bottom bracket torque sensor (eg. https://ebikes.ca/shop/electric-bicycle-parts/torque-sensors/erider68-4b.html), but was after advice on whether it would be possible to buy a cadence sensor rear hub kit and then add this torque sensor to it in place of the cadence sensor.

 

[vfr400]

Torque sensors give very little advantage if any. In fact some would argue that overall they have disadvantages.

Cadence sensors got bad rep from the early days when there were big delays in the power kicking in and long run-ons after stopping pedalling. Decent modern controllers don't do that. When choosing a kit with a cadence sensor, the response time is an important characteristic. Make sure you choose one with a quick response. Once started with such a system, I'd be surprised if you felt the need to change it.

 

[Bikes4two]

HI @RogerA - I'm new to ebiking too - thank goodness for the informed like @vfr400 - I found this article HERE a useful discussion about torque vs cadence sensors. What I was/am unclear about is the controller side of things, as in are the different sensor signals (ie cadence or torque) the same and can you therefore use the same input point on the controller, or do you have to do something different?

 

[RogerA]

Thanks for the replies so far. My wife has a bike with cadence sensor (Roodog Chic), and I've tried it, but don't like the way the power is delivered, and would prefer something that worked more the way I understand a torque sensor does with it multiplying your own effort.

If I could buy a cadence sensor kit, but then add a torque sensor, I would always have the option to revert to cadence sensor if I wanted, but as @Bikes4two asked, I'm unclear if/how this can be done.

I assume the Woosh controller can have a torque sensor as they used to offer one, but is it a simple plug and play, or is some programming required, and is that possible without specialist hardware/software?

 

[wheeliepete]

You need a dedicated torque sensor controller, but there is not a lot of choice. This one will work with the e-rider BB, but at 12A is a little low powered. I would go for a 48v system to improve this. Your wife's bike may have speed control which gives full power to a given speed in each level and is fitted to alot of oem bikes. A system with current control is a much better choice and feels totally different to ride.

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[vfr400]

Thanks for the replies so far. My wife has a bike with cadence sensor (Roodog Chic), and I've tried it, but don't like the way the power is delivered, and would prefer something that worked more the way I understand a torque sensor does with it multiplying your own effort.

If I could buy a cadence sensor kit, but then add a torque sensor, I would always have the option to revert to cadence sensor if I wanted, but as @Bikes4two asked, I'm unclear if/how this can be done.

I assume the Woosh controller can have a torque sensor as they used to offer one, but is it a simple plug and play, or is some programming required, and is that possible without specialist hardware/software?

You can't change from one to the other without changing the controller.

I'm not sure what control system the Roodog uses now, but I know that they used to be rudimentary speed control systems. You also have to differentiate between controllers that use speed control and current control for the pedal assistance. I would say that it's almost certain that the Roodog still uses speed control if you didn't like it. Speed control gives a high initial current when you pedal. Current control is a lot better. For kits, a KT controller is the only one that definitely gives current control, though there are some kits that use Bafang and LiShui controllers that probably do.

It's not as simple as what type of sensor you use. You can get controllers with torque sensors that have terrible power algorithms, controllers with cadence sensors that are really nice, and every other combination and place in the spectrum. The Bosch and Shimano control systems use inputs from the torque sensor, crank speed sensor and bike speed sensor in combination to get their power characteristics. A single torque sensor will never be as good.

 

[Nealh]

The Roodog as vfr has said will probably use a basic cheap speed sensor (these use a 3sp control ) one can't compare it against other cadence sensing kits like the excellent KT's or even the Lishui's with current control and 5 PAS current delivery levels.

 

[RogerA]

Thanks for the responses. It sounds as if I need to ask some questions about the controller before ordering a kit.

If I go for a cadence sensor kit with current control, do you suggest I install brake sensors? I've been told they're not required with cadence sensors.

 

[Nealh]

Thanks for the responses. It sounds as if I need to ask some questions about the controller before ordering a kit.

If I go for a cadence sensor kit with current control, do you suggest I install brake sensors? I've been told they're not required with cadence sensors.

Only needed if a throttle is used, the good current controllers have very little run on.

 

[vfr400]

Thanks for the responses. It sounds as if I need to ask some questions about the controller before ordering a kit.

If I go for a cadence sensor kit with current control, do you suggest I install brake sensors? I've been told they're not required with cadence sensors.

I've never had brake sensors on my bike, which has a throttle and KT controller. The only time I miss them is when turning very tight corners because the motor kicks in too soon. I could add a push-button cut-off switch instead, but it's not worth the effort considering the small inconvenience.

If you drop your bike and break the throttle, you get half throttle until you switch off the control panel or battery. Again, it's not a big deal, but people that don't know better try to stop the motor with the brake, which blows the controller.

 

[mechaniker]

just my 2cent.
A pedelec with torquesensor is way better and natural as a pedelec with speedlimit or current limit or a mix of cadence and current.
Don´t get me wrong every system has some advantage but as long i´m not disabled or lazy to give some own effort Into cycling I prefer Torquesensor controlled pedelec because it give´s a more natural way of bike-riding feeling. If you give more own effort when pedaling you get more support back.
Problem is that on the market are only torque sensing BB with square tapered BB axle, this is so old fashioned I couldn´t get over it on my private bike, I simply don´t want it......
So I inveted on my own a torquesensor for shimano-Hollowtech-II BB which I´m riding on our LISHUI-Controller show-bike for testing purposes and it does a very good job so far. It has a perfect chainline and good response from the sensor and even if something goes brocken, in compare to all the other BB´s on the market, it could be repaired for just a few euro;-) The Sensor is already intl.-patented and if no setback occur my boss will launch it this year

Another advantage is if you have a good working torquesensor-system you don´t need 5-step anymore, 2 step´s are enough one for normal days and one for a lazy day or in the mountains.

 

[Woosh]

torque sensors have two disadvantages: prone to malfunctioning and high replacement cost.
cadence sensors are generally very robust.

 

[mechaniker]

@Woosh you are absolut correct.
With my Shimano Hollowtech-II Sensor invention this problem will have an end, even a amateur with too left hand could repair the important part of my sensor without special tools for less than 10euro As a mechanic I come from the repairside of things and I focus automaticly not only on the installation side but on the repair side as well

 

[StuartsProjects]

So I inveted on my own a torquesensor for shimano-Hollowtech-II BB which I´m riding on our LISHUI-Controller show-bike for testing purposes and it does a very good job so far

Sounds interesting, are you able to say in general how it works ?

Does it replace a 'standard' PAS sensor directly, or does it need specific firmware in the controller for it to operate ?

 

[vidtek]

Since getting on my bike again now back in the UK I have tried both front hub and rear hub cadence bikes. The rear hub was more natural, although both bikes felt more like a powered small motorbike than a bicycle.
Whoosh supplied a torque-sensor Tongsheng Mid-drive TSDZ2 kit that I fitted to a Specialized Crossroads frame and it is by far the best cycling experience I have had on an e-bike. It just feels so natural but requires effort to climb hills just as a bike with no assist. I find the assist up the hills is just right, not too much but just enough to stop me from breaking a sweat. Of course with the throttle I need not pedal at all up most hills. Being a naturally lazy sod I need the exercise that this bike provides, not sure I would do the same with a cadence sensor kit.

 

[vfr400]

The main disadvantage with torque sensors is simply that you have less choice about how hard you pedal. With a decent controller and cadence sensor you can pedal as hard or not hard as you want in nearly all circumstances. It's not about being lazy.

I can see some advantage for torque multiplication systems when doing tricky manoevring, like off-road riding , but for normal cycling, like touring, commuting, shopping and other utility use, it makes absolutely no sense to me, even if it does feel more natural.

Ultimately, you want an electric bike to make your cycling easier. How you get that is up to you different people get it through different solutions. When I read discussions about it, I'm surprised at how so many people pass judgement based on misinformation. Typically, they try a cheap Chinese bike with the crappiest control system, then condemn all hub-motors and cadence systems.

 

[vidtek]

The main disadvantage with torque sensors is simply that you have less choice about how hard you pedal. With a decent controller and cadence sensor you can pedal as hard or not hard as you want in nearly all circumstances. It's not about being lazy.

I can see some advantage for torque multiplication systems when doing tricky manoevring, like off-road riding , but for normal cycling, like touring, commuting, shopping and other utility use, it makes absolutely no sense to me, even if it does feel more natural.

Ultimately, you want an electric bike to make your cycling easier. How you get that is up to you different people get it through different solutions. When I read discussions about it, I'm surprised at how so many people pass judgement based on misinformation. Typically, they try a cheap Chinese bike with the crappiest control system, then condemn all hub-motors and cadence systems.

The bikes I tried were all UK made and supplied. A Sunbear step-through and a
Freego Eagle, not cheap Chinese imports. I still much prefer the torque sensor ride, it is far more natural. Maybe it doesn't suit everyone, that's ok we are all different.

 

[mechaniker]

are you able to say in general how it works ?

I could tell but since I´m just the employee who designed and invented the sensor...... the legal part belongs not to me so I better keep my mouth shut for now, sorry.
I´ve setup my torque-sensor so that it need a PAS as well for safty reason but I could setup without PAS. The controller need´s a specific software and input terminal that can interpret the different signals. Since I work for LISHUI-Controller I´m able to setup the Lishui-software in any way I want and what I can´t do my colleagues at headquarter can do.

For me it was just a fun project and I only wanted to proof wrong all the manufacturer´s who told me for years "uhhh....arrgg... Hollowtech-II, to stiff, we tried but failed, to difficult, impossible, blabla...."
Last thing to do is now a lot of testriding, the first one thousand kilometer works perfect so far ;-)

I extra developed a Ebike test-bench which even could drive the bike on it´s own with automatic mode. It is possible to adjust any resistant from 50watt to 800watt to the bike in drive mode but a friend said "run real test on the road...only this give real feedback"
****, I hate to agree and he further said since my weight is way to much it will be a real challenge for the rider, the bike and the sensor as well

@vfr400
like I said everyone is different. My retired neighbour and my wife like speed-limit, my daugther like cadence with current limit and my friend like a combination of of both. Everyone has his own reason why he like a specific setup
I drove now ebike for nearly twenty years with countless testridings of hundred´s of differnet models for bike-manufacturer from asia and europe due to my job. Sometimes I wonder about the strange setups on some bikes but it is not my job to critisize them as long their customer is happy and he can sell the bike then our sales is happy too;-)
But to me personaly and for now torquesensor-system is the bike of my choise, I´m forced to pedal with own effort like a normal bike to get support and If I want more support I need to push the pedal harder to get my reward, I like it because it feels natural.
EU is working on law´s to get the PAS-System cancelt but I think restriction is never a good choise let the people decide what they want, but the speed limit is one of the rare point that make sense to me to keep a pedelec simple as a bicycle for everyone from 10-90> years of age

 

[vfr400]

The bikes I tried were all UK made and supplied. A Sunbear step-through and a
Freego Eagle, not cheap Chinese imports. I still much prefer the torque sensor ride, it is far more natural. Maybe it doesn't suit everyone, that's ok we are all different.

They are indeed both cheap Chinese imports. Neither of those were made in UK. Freego always had speed control controllers - some of them very rudimentary indeed. Freego were always relatively cheap Chinese bikes with higher than average UK prices because you were paying ffor their good support network rather than the bike itself. The Sunbear would be even worse because it has a high torque motor, which is very bad under speed control.

I'm not surprised that you preferred a torque sensor system to those two. Neither represents the epitome of control systems, though I'm sure that they'd be adequate for some people.

 

[vidtek]

They are indeed both cheap Chinese imports. Neither of those were made in UK. Freego always had speed control controllers - some of them very rudimentary indeed. Freego were always relatively cheap Chinese bikes with higher than average UK prices because you were paying ffor their good support network rather than the bike itself. The Sunbear would be even worse because it has a high torque motor, which is very bad under speed control.

I'm not surprised that you preferred a torque sensor system to those two. Neither represents the epitome of control systems, though I'm sure that they'd be adequate for some people.

You have your opinion, it doesn't tally with my experience.