Torque sensor vs Cadence...

EasyRiderDude

New Member
I have just begun the daunting task of researching the different brands, models & technical features available on eBikes. (No small task, lol) My aim is to buy a bike (maybe two,) that has the features, performance, comfort, reliability & customer support that meets my needs. EBR YouTube videos are very helpful.

One aspect I do not see addressed much is torque sensor verses cadence (how hard you are pedaling.) Many of the mid range bikes have only the cadence type sensing which from my understanding, only senses that you are pedaling but not how hard. (So the motor applies the full PAS power whenever you pedal? ...Like a on/off switch?)

On the other hand I understand that bikes fitted with a strain gauge type torque sensor, senses how hard you are actually pedaling & responds with a proportional amount of electrical assist.

I have a friend who owns several eBikes & he says it's all about torque sensing & that a cadence type system is vastly inferior to the torque sensor. Is there actually a big difference in the way the two systems work & more so, is there really a big difference in the way each bike performs?

Anyone with experience riding both types of sensing?... do you feel that one system works better than the other and if so why? Can you explain any advantages or disadvantages to either?

Oh... and for the record, I anticipate doing mostly street riding, paved & gravel roads, along with some lite trail excursions.

Happy riding to All & thanks for your input!

Ride On... :cool:
ERD
 
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Lightning P38

Active Member
I have just begun the daunting task of researching the different brands, models & technical features available on eBikes. (No small task, lol) My aim is to buy a bike (maybe two,) that has the features, performance, comfort, reliability & customer support that meets my needs. Your YouTube videos are very helpful.

One aspect I do not see addressed much is torque sensor verses cadence (how hard you are peddling.) Many of the mid range bikes have only the cadence type sensing which from my understanding, only senses that you are peddling but not how hard. (So the motor applies full power whenever you peddle?)

On the other hand I understand that bikes fitted with a strain gauge type torque sensor, senses how hard you are actually peddling & responds with a proportional amount of electrical assist.

I have a friend who owns several eBikes & he says it's all about torque sensing & that a cadence type system is vastly inferior to the torque sensor. Is there actually a big difference in the way the two systems work & more so, is there really a big difference in the way each bike performs?

From your vast experience riding both types of sensing, do you feel that one system works better than the other and if so why? Can you explain any advantages or disadvantages to either?

Thanks in advance and keep going with the Great work on EBR!

ERD

My 500 watt motor uses a cadence sensor. It has five pedal assist levels. And you can change the pas level on the fly.
The speed for each pas is:
1 = 5 mph
2 = 10mph
3 = 15 mph
4 = 20 mph
5 = 28 mph.

The motor gently applies power while you pedal to bring your speed up to that level. If you are going up hill, the speed Will be reduced due to the bigger load on the motor.

I usually ride in 3 pas. If I want to go slightly slower, I coast. If I want to go faster I select pas 4. I have a 9 speed cassette, so I just shift up based on what PAS level I have selected.

I can start out in any pas setting, depending on what top speed I desire.

I don’t know if torque sensors allow you to select a power setting.
 

Sierratim

Well-Known Member
My current ebike, a Specialized Vado 5, has torque sensing. It applies power as soon as it senses pedal pressure. There's no delay waiting for a wheel revolution, or partial revolution, so starting on an uphill is pretty easy. The amount of power depends on the assist level you've selected and the settings you've specified in the Mission Control app. The default settings work for many riders but there are several,posts that discuss alternative settings.

My wife and find this to provide a bike that responds smoothly to changes in pedalling effort and, as I mentioned, makes starting on a hill easier than a mech bike. Select any assist level and apply pressure, off you go!
 

AHicks

Well-Known Member
Not all cadence sensor software is created equally, so there can be quite a difference from a practical stand point from one bike to the next. This is one of the reasons you'll hear that riding a bike before buying it is a good plan.

My 500 watt motor uses a cadence sensor. It has five pedal assist levels. And you can change the pas level on the fly.
The speed for each pas is:
1 = 5 mph
2 = 10mph
3 = 15 mph
4 = 20 mph
5 = 28 mph.

The motor gently applies power while you pedal to bring your speed up to that level. If you are going up hill, the speed Will be reduced due to the bigger load on the motor.

I usually ride in 3 pas. If I want to go slightly slower, I coast. If I want to go faster I select pas 4. I have a 9 speed cassette, so I just shift up based on what PAS level I have selected.

I can start out in any pas setting, depending on what top speed I desire.

I don’t know if torque sensors allow you to select a power setting.

P-38 has done a nice job describing "speed" based cadence software. You can see that the different PAS (pedal assist) levels must be changed to change your speed.

The "other" major type of cadence sensed PAS is WAY different, and offers a much more normal experience to my way of thinking. It does this by allowing a certain amount of power to the motor, depending on PAS level chosen. This amount of power doesn't change at ANY speed. If you want more "assist" you dial up the PAS level and it supplies more power to make it easier to pedal. You want to "ghost" pedal with no effort? Set the PAS as required.

For instance - in PAS 1 my bike will have less than 100 watts available for the motor to assist you. It actually varies if you look at the watt meter, bouncing around from about 65 watts up to 100 (keep in mind the controller uses about 50 watts for internal housekeeping), but you feel none of this. It's super smooth, with no jerky on/off as your speeds change. Lets say you make a corner, and the wind direction changes to something hitting you in the face, making it more difficult to pedal. Bumping up to PAS 2 doubles the available power (to 180-200 watts or so), cutting the effort to maintain the SAME speed you were going by 1/2. Hills the same way, or maybe the pavement turned to grass. Set the PAS level for the effort you want to put into pedaling - up to level 5, and it just adds the power you want - no more - and speed has nothing to do with it. Going faster takes more effort, so you dial up the PAS level to reduce the effort to what you are looking for.
 

EasyRiderDude

New Member
Thanks for your feedback. That's an interesting control philosophy AHicks. What make & model bike is that?
I totally agree that a test drive is pretty important but living in a smaller city in Northern Ontario there may not be to much in the way of test drive opportunities. There is a shop or 2 in town however that I have yet to check out.
 

AHicks

Well-Known Member
Unfortunately, the only production bike I KNOW OF that uses this system for sure is sold by Bolton, at Boltonbikes.com. They are a smaller operation for sure.

The electronics (controller and display) are by KT (Kunteng) which is generally only available on the aftermarket. The ones I know of anyway. What I am not sure of is whether KT is the only ones using this type of cadence software. With the science evolving as quickly as it is, if this is the case, I can't see it staying that way for long. Maybe others can chime in on this....

What I find striking, is that the torque sensing systems, the ones I'm familiar with anyway, work so similarly - by changing the amount of power available to the motor with varying amounts of power established by each PAS level (higher PAS level = more power).

My bike is a very modified RAD City, with one of the modifications being an aftermarket KT systems controller and display. -Al
 

PDoz

Well-Known Member
With the science evolving as quickly as it is, if this is the case, I can't see it staying that way for long. Maybe others can chime in on this....

What I find striking, is that the torque sensing systems, the ones I'm familiar with anyway, work so similarly - by changing the amount of power available to the motor with varying amounts of power established by each PAS level (higher PAS level = more power).

You're right about the tech developing quickly , although at the higher end of the market the delivery is even more sophisticated / complicated / subtle than you describe.

We're now riding bikes that combine multiple sensors - torque, cadence, speed, acceleration and incline. I think lean as well. The rider has the ability to dial in varying assistance levels and enjoy a natural feeling cycling experience that modifies ALL that data in different ways to provide a different feeling in each setting. Plus play with our phones and change those settings. What could possibly go wrong?

I've had the luxury of riding my giant with a 2018 and 2020 yamaha pwx motor and the technology leap between the 2 has been impressive -but in real terms probably only a subtle improvement in an already exceptional ride.

I have 6 modes at the bar switch, 6 sensors, and I think 6 different options on how much assistance each mode is set at via the app : 666....wouldn't a throttle be safer?

eco - I can use my phone to program that at anywhere from 50 to 125 % nominal "assistance", but regardless of what level chosen I get an instant but gentle response to torque , variable depending on how much torque applied but also varied across the cadence range . The assistance gently tapers off around 70-90 cadence depending on the torque AND speed I'm riding. It's like riding with a tail wind but VERY much like riding a normal bike, biased towards efficiency rather than speed.

power is the other extreme - 360% of assistance, all the way out to about 120 cadence, instant and aggressive - especially if you punch the cranks at low cadence AND low bike speed in a low gear! Yet somehow this hyperactive race horse listens to the victim on it's back and does exactly what is asked - so long as you either ask gently or have the skill to cope with the consequences. Pure fun, but exhausting. Like being 16 again but also down hill with the wind blowing a gale . Amazing for tackling technical steep climbs - instant , aggressive, but controllable - it shouldn't be possible to have all 3.

Oh...and then there is auto for 2020 - technology takes over. Some boffin in computer land has decided that on that incline, at that speed, with that level of pedal assistance and cadence you probably want somewhere between 50 and 250% of torque amplification.....and somehow it's seamless. Disturbingly so.....until the boffins have a bad day at giant hq , stuff up the latest software, and we the consumer wish we just had a throttle.
 

zzRider

Active Member
Thanks for your feedback. That's an interesting control philosophy AHicks. What make & model bike is that?
I totally agree that a test drive is pretty important but living in a smaller city in Northern Ontario there may not be to much in the way of test drive opportunities. There is a shop or 2 in town however that I have yet to check out.
You didn't mention what type of riding you are doing (i.e., what terrain). That could help determine if you really need torque sensing or not. There was a good video posted recently here on torque vs cadence sensing and pros/cons of each. If you are hard mountain riding and standing on your pedals a lot, torque may be better.

Here's the thread with the videos:
 
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GenXrider

Active Member
I have a friend who owns several eBikes & he says it's all about torque sensing & that a cadence type system is vastly inferior to the torque sensor. Is there actually a big difference in the way the two systems work & more so, is there really a big difference in the way each bike performs?

No, I wouldn't say inferior. There's been some negative feedback about some torque based sensor systems. For mountain biking, I would prefer torque sensor based PAS in general, but I'm actually looking to get a cadence sensor based PAS for biking on rural roads for exercise when I maintain a continuous cadence.

the cadence type sensing which from my understanding, only senses that you are peddling but not how hard. (So the motor applies full power whenever you peddle?)

No, cadence PAS doesn't necessarily automatically apply full power. Every bike that I'm aware of, even some cheap Walmart ones, have as assist level setting. On some bikes, such as the Ride1UP 500, you can even program the power of each assist level, to control the watts delivered in any particular assist level. When configured for 9 assist levels, it defaults to 25% on PAS 1.

ride1up500power.jpg


Note, it's "pedal", not "peddle". Different meanings.
 
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teskow

Member
I have a 2018 Juiced RC that has both cadence and torque sensing. At first I switched back an foreth to determine which I liked better. I never use the cadence anymore.
As someone said, cadence isn't equal on all bikes and I have only ridden the one I have.
 

ruffruff

Well-Known Member
I have one of each. Both mid drives.
1. Yamaha PW-se with torque sensing.
2, Bafang 750 with cadence sensing.

I greatly prefer the torque sensing. It feels more natural and there is a ramp up of power.
The cadence sensor is like a switch. When you start pedaling it throws the switch and you get full power up to the PAS level you have set. On my bike it's an all or nothing thing.

When I ride the cadence sensor bike with my wife, I notice I pedal and either catch her really quick and stop pedaling or put a lot of distance on her and stop pedaling. Kind of like a spring going in and out all the time.

With the torque, I can set the level and gear and just spin the pedals along with her.
 

GenXrider

Active Member
It sounds like you have one of those bikes that gives too much assist. One thing I like about the Ride1UP is that the lowest assist level in 1/9 defaults to 25% max power as shown in the previous post (chart) of mine, and you can program it to a custom level, so it's not overwhelming power when you pedal.

I've seen various posts about very unnatural torque sensor based PAS and that some have returned bikes or canceled their orders after hearing of problems with the torque sensor based PAS. I think I would prefer torque sensor based PAS on a mountain bike for the trails but not for cruising along on rural roads.
 

AHicks

Well-Known Member
I think it would be a BIG help, or a valuable feature, to be able to program your PAS, whatever type (cadense or torque sensing), to your own tastes. Too much or too little anything could be adjusted out. But that's probably asking for too much from an OEM.
 

linklemming

Well-Known Member
It sounds like you have one of those bikes that gives too much assist. One thing I like about the Ride1UP is that the lowest assist level in 1/9 defaults to 25% max power as shown in the previous post (chart) of mine, and you can program it to a custom level, so it's not overwhelming power when you pedal.

I've seen various posts about very unnatural torque sensor based PAS and that some have returned bikes or canceled their orders after hearing of problems with the torque sensor based PAS. I think I would prefer torque sensor based PAS on a mountain bike for the trails but not for cruising along on rural roads.

Could you provide more info on what unnatural torque based systems your referring to?
 

linklemming

Well-Known Member

So all torque based systems are now potentially troublesome since the bafang M600 has crappy programming? FWIW, the bafang m600 isnt a mainstream system like brose/bosch/yamaha/shimano.

Many complain of bad programming for some cadence based PAS systems, so can I use your logic and conclude that all cadence based PAS systems are potentially troublesome?

https://www.google.com/search?q=jer...rome..69i57.4985j0j7&sourceid=chrome&ie=UTF-8

I think what is common here is that badly programmed and/or designed systems are just that...bad whether torque or cadence based.

Bafang seems to be known for sometimes having bad factory defaults
https://electricbike-blog.com/2015/06/26/a-hackers-guide-to-programming-the-bbs02/

Many others I can show as well

In addition to my 3 current ebikes (all torque sensor based), I have built a bike a using a TSDZ2 mid drive(torque sensor with opensource software) and just recently a cadence based bbs02 with different parameters as mentioned above. In the end, I just cant stand cadence based PAS. Im actually building a bike now with a grin mac motor and throttle only.

Why do you think cadence based PAS is better for rural roads? I ride rural roads everyday, what am I missing?
 
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AHicks

Well-Known Member
I would never argue why you should enjoy what I prefer, it's pretty obvious to most the reason they make both types is because they are both popular. Is one type "best" or better? Oh please....save it for the choir.

I do agree about the software. My hope is that as the e-bike industry matures, folks will get the benefit of some thought placed on that factor at the OEM level. It sure seems a scattered roll of the dice at this point. It's obviously possible to have very nicely done torque and cadence software, as the aftermarket vendors have proven already....
 

6zfshdb

Well-Known Member
I can't stress enough the importance of testing as many bikes as possible before buying. What others like, you may not. In testing a dozen or so bikes, here is my takeaway:

1 - The torque and cadence sensors operate differently on almost every bike. Not all apply full power in every PAS mode. Some sensors are programmable, many are not.

2 - Torque and cadence sensors sometimes have a lag before power kicks in. This varies from a half to two crank revolutions on the bikes I tested.

3 - This is further compounded by the fact that the amount of power applied by both sensors in all PAS modes varies as the battery voltage drops. Some higher end models have voltage regulation which prevents this but all the bikes I tested did not.

4 - I found the cadence sensors on a couple of bikes to be excellent. The amount of power applied was acceptable to me in each PAS and I didn't feel a torque sensor was necessary. This however was not the case on all the bikes I tried. I also found the converse to be true with the torque sensor on a couple of bikes.

5 - With experience, I realized that my comfort level with the cadence and torque sensor performance varied during a ride. What I liked at the start was quite different than at the end.

I realize none of this answers your question. The point I'm trying to make is this: You are the one who decides what works best. By all means, take the advice of others but TEST RIDE and make your own decision!

After bike shopping for 18 months, I wasn't able to find a bike that fit all my requirements which had acceptable torque & cadence sensors. I finally bought a class 2 bike with both torque and cadence sensors as well as a throttle. That way, I have the advantage of all three. When I can't find a comfortable performance level from the sensors, I set the throttle to the speed I want and apply whatever level of pedal assist I choose. In this case, the bike isn't assisting me, I'm assisting it.

Please keep in mind all this was almost 3 years ago. A lot has changed in the market since then and you'll never know what works best until you experience it for yourself !!
 

TMH

Well-Known Member
One thing to really think about with a cadence sensor bike is whether you will be riding with others. My wife has 3 e-bikes in general rotation, 2 with torque sensors (including one with a Bafang M600, which she absolutely loves) and one with a cadence sensor. She also loves her bike with the cadence sensor. But, since we always ride together, she finds the bike with the cadence sensor more difficult to maintain my speed, when she is following me as a wind break. Simple answer is that she just passes me, and takes her turn pulling at the front of our 'pack of 2'. Of course this is never an issue for her when riding one of her torque sensor bikes.

I also agree with what was said above - Many bikes can be programmed at their display for a total of 3, 5 or 9 levels of pedal assist. Many ask (I did at first) "why would I want to have to cycle through and choose from 9 different levels?" The answer to me: To have more discrete control of a hub motored bike with cadence sensor.