PAS not torque sensing, will I be disappointed?

[Farther]

Planning on building a bike with a BBS02 with no throttle. I only want assisted power while peddling and not an electric motorcycle. In my research today I learned that the system will not be torque sensing and now I'm wondering if this is what I want to do.

I want the motor to apply more power when needed depending on conditions faced. Of course I will shift gears as needed, but I want a system that offers a natural feel, like a real bike, only with a boost.

The stock bikes I have ridden have behaved exactly like I want. They have been built on the Shimano Steps, or Bosh system, but prices are high and when the battery needs replacement you almost need a loan to afford the high cost!

Is there a way to build what I want, or do I have to buy a stock bike to get it?

 

[JRA]

Check out the TSDZ2 kit. Same amount of power as the BBS 02 but torque sensing PAS. Several threads online about them.

 

[Dewey]

Also check out Grin Tech’s bottom bracket torque PAS sensors for hub motors, you’ll need to drill a hole in your bottom bracket shell for one wire.

I ride a BBS01 with no throttle and the motor has an operating power band it likes to be in so you’ll feel it accelerating until it reaches its preferred cadence and you’ll have to shift up to keep up unless you’re climbing a hill

 

[Farther]

Also check out Grin Tech’s bottom bracket torque PAS sensors for hub motors, you’ll need to drill a hole in your bottom bracket shell for one wire.

I ride a BBS01 with no throttle and the motor has an operating power band it likes to be in so you’ll feel it accelerating until it reaches its preferred cadence and you’ll have to shift up to keep up unless you’re climbing a hill

Do you have the torque sensor?

 

[Dewey]

Do you have the torque sensor?

No but I recall from reading on Grin Tech’s website the German Thun sensor reads the left pedal only, the Taiwanese TDCM reads both and has a higher PAS pole count plus it’s cheaper, unsure about the Chinese Sempu sensors. There is more info on the Endless Sphere ebike forum.

 

[harryS]

If you set the BBS02 to 9 level pedal assist, you should find a speed and pedal feel that feels close to bike like pedaling. Where it feels too assisted is when you ride in a speed below the power band of an assist level. Really finicky users will buy the programming cable and tune those power bands even further. Not me.

Also no reason to be a purist and spurn the throttle. Install it and just don't use it.

 

[Farther]

If you set the BBS02 to 9 level pedal assist, you should find a speed and pedal feel that feels close to bike like pedaling. Where it feels too assisted is when you ride in a speed below the power band of an assist level. Really finicky users will buy the programming cable and tune those power bands even further. Not me.

Also no reason to be a purist and spurn the throttle. Install it and just don't use it.

Great info. Can't ride on bike trails with a throttle installed.

 

[tompat]

I learned that the system will not be torque sensing and now I'm wondering if this is what I want to do.

Find a bike dealer that sells cheap chinese e-bikes. You'll certainly find a bike there that has no torque sensor. Take it for a spin. I've done it and I find them horrible. Not only did the bike have a 1 second delay before the assist kicks in but it also had the same delay when letting go of the pedals. It just kept on assisting for a second or two. Very scary feeling.

 

[tomjasz]

These days there are PAS sensors that are better developed and when coupled with device like a Cycle Analyst, CA3, have a very good feel.
Here's one of the best discussions... http://www.ebikes.ca/learn/pedal-assist.html

Which is Better?
This is one of those questions with an "it depends" kind of answer. Many people will assume that a torque sensor is ideal and represents the gold standard for PAS control, and that the basic PAS sensors represent a poor but inexpensive alternative. We don't think it's that simple, as people who prefer to regulate motor power independently from their pedal effort will be better served with a basic PAS setup.
A torque based control directly couples the motor power to the rider's power output. That means that going uphill you need to pedal hard to get sufficient power to climb, while on the flats or downhill’s if you pedal hard you will end up getting motor power when you don't actually need or want it. The overall experience is similar to riding a non electric bike, where your riding efforts vary significantly with the terrain; sweat going up, take it easy going down. If that is the behavior that you want then it works extremely well.
On the other hand, one of the benefits of an ebike is that you can use the motor to decouple the terrain from how hard you need to pedal. The motor can make up the difference between what your legs are putting out and what is required for the given hill and headwind. If you want to be able to ride comfortably with a given effort that doesn't change much whether going up or down, then you'll need the motor to put out lots of power when climbing, and then minimal to no power on the downhills, even while leg power remains the same. A basic PAS sensor with an easily handlebar adjustment for the PAS power level allows you to achieve this behavior quite nicely. It provides independent control of motor power and your pedal effort like a throttle, but without needing to constantly hold a throttle position.

 

[Johnny]

I disagree that "cadence only vs additional torque sensor" is a matter of preference.

Since bike feel depends very much on the force you apply to the pedals , a sensor measuring this force improves the feel of the bike significiantly. The amount of exercise you want can be very nicely tuned with a torque sensor since at each pedal stroke you know how much power is coming from you so it actually adds to the functionality of the bike.

In short I believe more sensors is simply much better in this case.

I think it is time for all of the kit manufacturers to switch to torque sensor from cadence only.

 

[AdamC]

I'm kinda leaning towards the combination of pas sensor and throttle. run the pas like a cruise control and throttle good for the hills and quick starts.....but right now only have a throttle, likely to add PAS in the near future

 

[harryS]

AdamC, did you have a brushed motor controller that supports pedal assist?

Some guys have made DIY minicontrollers with the Arduino that can deliver a DC voltage for a throttle from the signals off a cadence sensor. Probably good for a month of tinkering, if you're into Arduinos.

 

[AdamC]

I don't do electronics!!!! which is hilarious since I do ebikes....... but there is a guy on endless sphere who sells a voltage pas kit for brushed motors...

 

[harryS]

That's great!

 

[Rooster]

Do you have the torque sensor?

You can't run a bottom bracket torque sensor with a mid drive but IMHO all the torque sensor crap is a bunch of hype. Get the bbs02 and enjoy. And by the way, I have a bike with a torque sensor and I'm not impressed.

 

[tompat]

And by the way, I have a bike with a torque sensor and I'm not impressed.

What bike with a torque sensor do you have?
I have a Bosch Performance-powered bike and the assistance kicks in instantaneously and gives the feeling that your legs are 3x stronger.
The non-torque sensored bikes I've tried have all had a delay when the assist needs to kick in and out. It's like there is an army of underground elves in your bottom bracket that needs to be woke up and told to get cranking. It just feels very unsofisticated.

 

[Rooster]

What bike with a torque sensor do you have?
I have a Bosch Performance-powered bike and the assistance kicks in instantaneously and gives the feeling that your legs are 3x stronger.
The non-torque sensored bikes I've tried have all had a delay when the assist needs to kick in and out. It's like there is an army of underground elves in your bottom bracket that needs to be woke up and told to get cranking. It just feels very unsofisticated.

Yeah, there's a little more than torque sensing going on in your $$$ German made motor. I agree, Bosch is badass but noisy and expensive. I have a juiced bikes ocean current that everyone knows I'm not happy with but we don't even want to go there. Juiced Bikes torque sensing has a delay as well like a bunch of little elves LOL that's a good one.