i am looking into removing the limit off my Kinetic 250w hub motor driven Ebike, not to break speed limits but after that its a weighty bike and i struggle to get it up to 30mph or close to it as where a standard bike i could do this no problem. dont get me wrong its lovely up hills. if i can do it it would be nice but i also dont want to burn the motor out. i would have thought it could cope with it just it has the limit to keep in check with laws and to slow us cyclists down .
If you take the 15 mph limit off, it's not an e-bike any more, but an electric motorbike.
That gets you into a whole load of potential hassle - insurance, MOT (which it would fail), breathalysers, points on your driving licence etc.
If you can do 30 mph on the flat with a standard bike, you don't need an e-bike; if it's downhill, e-bikes do that just as well as standard bikes, or possibly better, given the extra weight.
not to break speed limits but after that its a weighty bike and i struggle to get it up to 30mph or close to it as where a standard bike i could do this no problem. dont get me wrong its lovely up hills
Surely if you can make 30mph on the flat on a normal bike your legs have enough power to not need help on the hills? - lower gears possibly needed on the hills? That is, of course unless I have missed something.
As others have said, removing the limiter makes the bike illegal, whether you (electricaly) power it to over 15pmh or not.
not to break speed limits but after that its a weighty bike and i struggle to get it up to 30mph or close to it as where a standard bike i could do this no problem. dont get me wrong its lovely up hills
Surely if you can make 30mph on the flat on a normal bike your legs have enough power to not need help on the hills?
My thoughts too. 30 mph on the flat 'no problem' on a normal bike could certainly take the same up an Alpine col or two. I don't think I was ever capable of doing 30 mph on the flat. Didn't start until I was 50, though.
I'm wondering if the motor is preventing the bike going north of 15mph rather than cutting out at 15mph?
The bike can legally be pedalled or coasted above that but the motor can't assist beyond that.
Bill
“Ride as much or as little, or as long or as short as you feel. But ride.” ~ Eddy Merckx It's a rich man whos children run to him when his pockets are empty.
i am looking into removing the limit off my Kinetic 250w hub motor driven Ebike, not to break speed limits but after that its a weighty bike and i struggle to get it up to 30mph or close to it as where a standard bike i could do this no problem. dont get me wrong its lovely up hills. if i can do it it would be nice but i also dont want to burn the motor out. i would have thought it could cope with it just it has the limit to keep in check with laws and to slow us cyclists down .
any help and advise would be great
thanks
Scott
Putting aside the illegality (although I wouldn't If I were you) consider the effects of using the motor and battery of that system to assist you up to 30mph. The energy required to get there will go up exponentially with the value of the assisted speed. Unless you yourself are already constantly outputting 400+ watts, you'd drain the battery in no time at all. That particular motor would likely also run at max and overheat in even less time.
If you are a 400 watter, why have a motor at all?
Cugel
“Practical men who believe themselves to be quite exempt from any intellectual influence are usually the slaves of some defunct economist”.
John Maynard Keynes
Cugel wrote: ↑18 Aug 2022, 11:46amThe energy required to get there will go up exponentially with the value of the assisted speed.
It isn't exponential.
The energy needed to increase the kinetic energy goes up as the difference of the square of the speeds.
On the level as speed increases aerodynamic drag becomes the largest force to be overcome to maintain speed. The force of the drag goes up as the square of the speed, the power needed as the cube of the speed.
Cugel wrote: ↑18 Aug 2022, 11:46amThe energy required to get there will go up exponentially with the value of the assisted speed.
It isn't exponential.
The energy needed to increase the kinetic energy goes up as the difference of the square of the speeds.
On the level as speed increases aerodynamic drag becomes the largest force to be overcome to maintain speed. The force of the drag goes up as the square of the speed, the power needed as the cube of the speed.
Jonathan
Beat me to it! Quite so. Kinetic energy = 0.5 x m x (v squared).
No. You will be breaking the law if you do so. I would hope that people here, who do seem generally sensible, do no more than point this out to you.
i assume that you have found, as I have that ebikes are fine for pottering but when you want to exceed 15mph they are a bloody anchor. For me 25mph isn't out of the way on the flat on a normal bike ( Just about on a flat 10 mile TT anyway) but on the ebike 17 is hard work. All that weight and drag.
Anyway. No.
And you'll knacker the motor and when you try to warranty claim your derestriction will show,
not to break speed limits but after that its a weighty bike and i struggle to get it up to 30mph or close to it as where a standard bike i could do this no problem. dont get me wrong its lovely up hills
Surely if you can make 30mph on the flat on a normal bike your legs have enough power to not need help on the hills? - lower gears possibly needed on the hills? That is, of course unless I have missed something.
As others have said, removing the limiter makes the bike illegal, whether you (electricaly) power it to over 15pmh or not.
Riding it on the road without insurance & helmet having removed the limiter is the illegal bit.
....possibly but only if you wanted to give Grant Shapps, the Daily Mail and the Express further ammunition for ALL of us to ride bikes with registration plates...
..so if you could refrain from doing so it would be greatly appreciated...
Cugel wrote: ↑18 Aug 2022, 11:46amThe energy required to get there will go up exponentially with the value of the assisted speed.
It isn't exponential.
The energy needed to increase the kinetic energy goes up as the difference of the square of the speeds.
On the level as speed increases aerodynamic drag becomes the largest force to be overcome to maintain speed. The force of the drag goes up as the square of the speed, the power needed as the cube of the speed.
Jonathan
Yes, yes ... I use the word "exponential" only in that loose sense of increase/decrease in a nonlinear fashion.
Perhaps you would care to publish the graph of energy requirements agin' bicycle velocity - for each of 12 bicycle types of course, permed with the 7 rider shapes and with an accuracy no less than +/- 0.33%?
Cugel
“Practical men who believe themselves to be quite exempt from any intellectual influence are usually the slaves of some defunct economist”.
John Maynard Keynes
Cugel wrote: ↑18 Aug 2022, 11:46amThe energy required to get there will go up exponentially with the value of the assisted speed.
It isn't exponential.
The energy needed to increase the kinetic energy goes up as the difference of the square of the speeds.
On the level as speed increases aerodynamic drag becomes the largest force to be overcome to maintain speed. The force of the drag goes up as the square of the speed, the power needed as the cube of the speed.
Jonathan
Beat me to it! Quite so. Kinetic energy = 0.5 x m x (v squared).
Some confusion between kinetic energy and the energy required to overcome drag. Once a set velocity is achieved it is only overcoming drag and friction which require energy (on the flat). Drag goes up as a square of the speed so is exponential - twice the speed needs four times the energy. Kinetic energy is what goes into the brakes when someone pulls out in front of you
.
