eBike torque
 

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[Closed] eBike torque

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so I see eBikes have peak torque of 60 - 90 ish Nm. Seeing as my KTM 1290 is around 140 Nm eBikes must really fly!

(more likely it's a different measure.....)

Please explain to eBike luddite


 
Posted : 13/01/2021 9:46 pm
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How much power does your KTM have with that torque?

A 05ish F1 car has 300-350nm torque.

Broadly speaking, torque is more a measure of acceleration, whereas power is for top speed, so ebikes get up to their low top speed quickly.


 
Posted : 13/01/2021 9:48 pm
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Yeah torque is not power.


 
Posted : 13/01/2021 9:49 pm
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Power is torque times revs. Your KTM will have peak torque at 5000 rpm or something, the ebike at 70 rpm thats also measured at the crank for both - KTN will be a very different gearing to an e bike - KTM will be a reduction gear, the e bike a multiplication gear. so on the KTN the rear wheel is slower than the crank increasing rear wheel torque by the same factor as the gearing, the bikes rear wheel is faster or the same speed as the cranks ( well depending on gearing) so less rear wheel torque.

KTM will be 100+ BHP at the wheel, the e bike maybe 1/2 a bhp


 
Posted : 13/01/2021 10:01 pm
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I know torque ain't power......... KTM has 160 claimed bhp, about 100 ft lbs of torque. It's a bit of a monster, wheelies off the throttle in 3rd at 80 mph

I've ridden an eBike and I don't see how the torque can be anyway comparable


 
Posted : 13/01/2021 10:04 pm
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Itsd all about the revs - and the multiplication effect of the gearing.

someone worked out for me that on the tandem we can put out 300+ ft lb at the rear wheel - but at 35 rpm or so

wheelies off the throttle in 3rd at 80 mph

Wheras an ebike wheelies off the power at 0.5 mph


 
Posted : 13/01/2021 10:07 pm
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I’m swapping my 3.0 litre v6 for the TJ’s 😀


 
Posted : 13/01/2021 10:46 pm
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I suspect your v6 does rather more than 70 rpm. I have been up to the dizzy heights of 130 rpm but the valves started bouncing and then the head blew


 
Posted : 13/01/2021 10:52 pm
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Wheras an ebike wheelies off the power at 0.5 mph

now I get it!


 
Posted : 14/01/2021 8:11 am
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One way I use to describe is torque is the required force, speed is how fast you want to move the force and power is a combination of the two.

Say I want to pick a 10Kg mass straight up vertically.
Using the mechanics I have, it takes say 150Nm of torque to move.

This is a constant, no matter how fast I want to lift it.

Overall motor power is determined by how fast I want to lift it, so quicker equals faster output speed - which equals more motor power to generate the torque at the higher speed.

The ebike motor generates the same torque as a motorbike (for sake of argument), but the motor bike can generate it at 5000 rpm against say 60 rpm on the ebike - much more power required for the motorbike, hence the huge difference in performance.


 
Posted : 14/01/2021 8:26 am

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