Bosch motor clarification question

[Sparky731]

What is the difference between the Performance Speed motor that I have on my Trek Allant and the Performance Line Sport on my wife’s Trek Verve 4s?

Both are Class 3 28mph, but the Sport is rated at 65Nm while the Speed is rated at 85Nm.

What does Nm refer to?

 

[peterh_nz]

What does Nm refer to?

Newton metres (Nm) is a measurement of torque, rotational force.

Therefore 85Nm is a force of 85 Newtons at a radius of 1 metre. Or 1 Newton at 85 metres!

 

[Stefan Mikes]

What is the difference between the Performance Speed motor that I have on my Trek Allant and the Performance Line Sport on my wife’s Trek Verve 4s?

Both are Class 3 28mph, but the Sport is rated at 65Nm while the Speed is rated at 85Nm.

What does Nm refer to?

By a widely followed industry practice, it is the other way of saying the peak mechanical power of the Sport motor is close to 400 W while it is close to 530 W for the Speed one. The actual Peak Power of a given motor could be different because the motor torque as given by the manufacturer is a marketing figure that looks good on paper.

All Euro e-bike motors have the nominal continuous power of 250 W. The manufacturers do not want to clearly admit the Peak Power for almost all Euro e-bike motors is greater than 250 W, so they hide that fact behind the torque figures.

The conversion factor is 6.28 rad/s, or 60 rpm.

 

[Sparky731]

Newton metres (Nm) is a measurement of torque, rotational force.

Therefore 85Nm is a force of 85 Newtons at a radius of 1 metre. Or 1 Newton at 85 metres!

Your answer is really, really clear! Ok, not so mush.

And I was a physics major! I should remember this stuff!

So, the 85Nm motor (mine) requires less pedal torque than the 65Nm (wife’s) to propel the bike for the same distance?

Great! Now my wife has another reason to call me lazy!

 

[fooferdoggie]

Your answer is really, really clear! Ok, not so mush.

And I was a physics major! I should remember this stuff!

So, the 85Nm motor (mine) requires less pedal torque than the 65Nm (wife’s) to propel the bike for the same distance?

Great! Now my wife has another reason to call me lazy!

well only if you put out the same torque yourself. you wont get the max assist till you can really put out the power. the 65nm you need to be able to put out about 450 watts. that takes a really steep hill like a 20% grade with the 85nm I cant bottom it out. I was getting 550 watts out myself going up that hill and that was me maxed out. I could not tell if the motor hand more.,

 

[peterh_nz]

So, the 85Nm motor (mine) requires less pedal torque than the 65Nm (wife’s) to propel the bike for the same distance?

I would expect that if all other parameters were equal (total weight, assist level etc) and both bikes are ridden side by side, then the motor of each bike would be producing the same torque (power).

The difference in potential torque would only be expressed in scenarios of extreme demand, like on very steep slopes. The 85Nm bike would then have an advantage

 

[Sparky731]

I would expect that if all other parameters were equal (total weight, assist level etc) and both bikes are ridden side by side, then the motor of each bike would be producing the same torque (power).

The difference in potential torque would only be expressed in scenarios of extreme demand, like on very steep slopes. The 85Nm bike would then have an advantage

Good to know re:more power available during high demand such as hills.
My wife is a power hill climber few can keep up with. Including me!
But now I have NO excuse. No pity for me!

 

[BlackHand]

Worth mentioning that the PL Sport is a gen3 drive unit that has 65nm as a system2 motor but miraculously has 75nm when on a smart system bike.

Your gen4 Speed motor launched as a 75nm drive unit that quickly got upgraded to 85nm via firmware update after competitors released more powerful motors.

No telling what the actual difference in power between the 2 drive units is.