Differences between hub motor with Torque sensor vs mid drive motor

[fooferdoggie]

If you have an analog watch with a second hand, calculating your cadence is easy. Just count revolutions for 15 seconds and multiply by four. For me it is easiest while ridding to just double the number twice. So, if it is 15 revolutions in 15 seconds, you get 30, then 60. You have a cadence of 60. It is is 20, then you get 40, then your cadence is 80.

math is not fun while riding if it ever is. thats why they made bike computers.

 

[penserv]

Even presidents say math is hard....

 

[PedalUma]

There is also experience. You can develop a feel for these things over time like blind person who plays a violin or fretless bass. That experience is probably more important than the data sheet. I really like my 90nm bike with a 42 ring to an 11-47, nine speed cassette.

 

[fooferdoggie]

There is also experience. You can develop a feel for these things over time like blind person who plays a violin or fretless bass. That experience is probably more important than the data sheet. I really like my 90nm bike with a 42 ring to an 11-47, nine speed cassette.

yes but it takes practice so if you cant keep track of your cadence it would be nard to learn to keep it steady.

 

[Jeremy McCreary]

I use a $20 aftermarket cadence sensor from Amazon. (Not the kind used in cadence-sensing assist schemes.) It straps to one crank and reports crank RPMs via Bluetooth.

I use the RideWithGPS app on my phone to view the readings in real time. Cadence at a glance and still going strong a year later.

 

[PedalUma]

aftermarket cadence sensor

It is cool that it does not need an external pickup. It has an internal piece that flops with each revolution from up to down, measured against a timer chip, and Bluetooth. I tend to stay away from that sort of tech and prefer the 15 second method when getting the data. I understand that, that is the older non-digital way to take a pulse. Count the heart beats for 15 seconds, double and double again for the heart rate per minute. A prime athlete may have a resting rate of 10 for 15 seconds. Or, 40 for one minute. Remember when Nurses always had watches?

 

[Jeremy McCreary]

It is cool that it does not need an external pickup. It has an internal piece that flops with each revolution from up to down, measured against a timer chip, and Bluetooth. I tend to stay away from that sort of tech and prefer the 15 second method when getting the data. I understand that, that is the older non-digital way to take a pulse. Count the heart beats for 15 seconds, double and double again for the heart rate per minute. A prime athlete may have a resting rate of 10 for 15 seconds. Or, 40 for one minute. Remember when Nurses always had watches?

But it does use an external pickup. You can see it strapped to my left crank in the lower photo.

I learned to count pulse and respiratory rates in med school. Still prefer the sensor shown. Willing to glance down at my phone on the handlebars to make note of current cadence in real time. Otherwise, prefer to keep my eyes and brain engaged with riding.

 

[GizmoEV]

But it does use an external pickup.

Not according to the list of materials. An external pickup would be like what my old CatEye had where there was a reed switch triggered by a magnet. Two items needed for the trigger. This item has nothing except what you mount to the crank arm.

 

[Jeremy McCreary]

Not according to the list of materials. An external pickup would be like what my old CatEye had where there was a reed switch triggered by a magnet. Two items needed for the trigger. This item has nothing except what you mount to the crank arm.

The term "external pickup" is apparently much more specific than it looks. The sensor strapped to my left crank is external to the bike, and it picks up the chainstay as the crank goes by. As a Hall effect sensor, it's also fundamentally magnetic.

Oh well, wouldn't be the first misleading bicycle term. Many members use "PAS" as if it were synonymous with simple cadence-sensing pedal assist. But torque-sensing assist is also a Pedal Assist System.

And the typical ebike "cadence sensor" doesn't measure cadence at all — at least not as "cadence" was defined prior to the advent of ebikes. It just detects the presence or absence of crank rotation.

 

[GizmoEV]

The term "external pickup" is apparently much more specific than it looks. The sensor strapped to my left crank is external to the bike, and it picks up the chainstay as the crank goes by. As a Hall effect sensor, it's also fundamentally magnetic.

There is the difference, the word "external" is in reference to the device, not the bicycle. That is how it has been referred to ever since the first cyclo computers came out.

 

[penserv]

I finally solved my front chainring size dilemna. It turns out that if you buy a narrow wide chainring in a 104BCD, you're pretty much limited to an aluminum alloy ring and those are uniformly 4mm in thickness. With an Al-alloy ring, I'd be limited to a 38T chainring with good clearance on the chainstay. I could go to 40T with about 1mm clearance (or less) and that's too risky for me. If you could find a steel narrow wide chainring, they are generally about 2mm in thickness and almost impossible to find. However, if you buy a triple crankset, all the chainrings are steel and using those rings I have a choice of 42T or 44T (with less than 1mm clearance on the chainstay), so I'll probably go with the 42T because there is better clearance. All the rings in a triple are stamped and the teeth in the ring are slightly offset from the mounting holes, which affords you a bit of play when attaching the crank spider onto the BB. One way will give you better clearance on the chainstay and the opposite way will result in a better chainline. In my case, with good clearance on the chainstay, my chainline will be about 50mm, which I am going to have to live with. These rings are not narrow wide. They are just old fashioned uniform teeth, so you have to use a chain guide to ensure the chain doesn't slip off. Triple cranksets are cheaper than individual narrow wide rings and have the durability of steel.