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Derestricting motor to 500w - will I notice much difference?

Posted: 14 Sep 2020, 7:39pm
by Rob Archer
I've recently fitted a Cyclotricity mid-drive E-assist kit to my Surly Disc Trucker. I'm really pleased with it. I do have the throttle fitted (I know it's not road-legal in the UK) and find it handy if I need to accellerate quickly, like on a roundabout, or for the rare hill (I live in West Norfolk!). I have the codes to deregulate it from 250W to 500W. Apart from the legal issues, would I actually notice much difference? How much would it affect my range (currently about 30 miles)? I mostly use the lowest assist setting unless I'm fighting a Fenland headwind. I suppose I'm asking is it worth breaking the law for? Most of the people I know using e-bikes are using 500 or 1000W motors.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 14 Sep 2020, 10:15pm
by hemo
Derestricting the wattage probably also allows more current to flow, if so then yes range will suffer.
If the controller is rated as 22 or 25a max then I would think in 250w mode current draw will be 15 -17a and then derestriction will also release more current.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 14 Sep 2020, 10:19pm
by roubaixtuesday
OK, so this may sound harsh.

But stop being selfish and just comply with the law.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 15 Sep 2020, 8:02am
by Oldjohnw
roubaixtuesday wrote:OK, so this may sound harsh.

But stop being selfish and just comply with the law.


Agree. No wonder ebikes get a bad name.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 15 Sep 2020, 11:17am
by NickWi
Rob Archer wrote: I suppose I'm asking is it worth breaking the law for?


Ultimately that decision is yours and yours alone, just remember this: In the infamous Charlie Alliston case the police used his social media posts against him. You've just gone on public record stating that you both know what the law is and that you're prepared to break it for personal gain.

Now, in practice the odds of the Police pulling you over for a 'just a routine check sir' are slim, and even slimmer are the odds of a that PC knowing the fine details of e-bike laws, but, and this is the big but, you have an incident that warrants their full investigative powers and the law could come down on you like a ton of bricks. The points and a fine may not bother you, but driving without insurance is a Criminal Offence and could haunt you for years. It also goes on the CRB records and that may affect you chances of getting certain types of job.

As roubaixtuesday said: . . . . . . ^

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 16 Sep 2020, 8:25am
by Gangzoom
Rob Archer wrote:How much would it affect my range (currently about 30 miles)


A very simplicity way to think about is if you double the power output and the battery remains the same size you will halve your range, presuming you use the extra power.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 16 Sep 2020, 5:00pm
by NickWi
Gangzoom wrote:A very simplicity way to think about is if you double the power output and the battery remains the same size you will halve your range, presuming you use the extra power.


Isn't there also something about doubling the speed means squaring the power due to the extra drag of the air?

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 16 Sep 2020, 5:14pm
by Jdsk
NickWi wrote:
Gangzoom wrote:A very simplicity way to think about is if you double the power output and the battery remains the same size you will halve your range, presuming you use the extra power.

Isn't there also something about doubling the speed means squaring the power due to the extra drag of the air?

Force (drag) goes up as square and power as cube.

But I don't know what "range" means in this context... is that on battery alone with no human input?

Jonathan

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 18 Sep 2020, 1:56pm
by mercalia
Easly this week there was an acident near Sainsburys Streatham Common of an ebike rider who took his chances beause he was powered.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 18 Sep 2020, 6:52pm
by Manc33
"Getting the car to do 155 MPH, frankly isn't really very difficult, the Veyron needs just a piffling 270 horsepower to reach that speed - but 253? Crikey! The faster you go, the more mother nature tries to hold you back, so to do the next 100 MPH (the 100 MPH that takes you up to 250) needs another 730 horsepower" - James May talking about the Bugatti Veyron on Top Gear.

My point with that is, if you're halving a 500W motor to 250W, it's plausible that your speed won't be halved, you might get 75%+ of the speed you were getting with 500W.

When I was using a 250W motor on a bicycle, it pushed me up to about 15 MPH.

What does 500W push you to, let me guess... about 20-25 MPH?

You guys really need to stop cheating. :lol:

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 19 Sep 2020, 11:12am
by hemo
Any speed is down to setting the lcd limit and how fast one can pedal, one will see better acceleration and power on inclines as the max current will be released.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 19 Sep 2020, 3:38pm
by mjr
mercalia wrote:Easly this week there was an acident near Sainsburys Streatham Common of an ebike rider who took his chances beause he was powered.

How is this relevant? Was it derestricted or fitted with a throttle?

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 19 Sep 2020, 3:44pm
by Syd
As Roubaix says and remove the ‘throttle’ which you already admit to knowing it’s not road legal.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 23 Sep 2020, 11:40am
by Rob Archer
I seem to have kicked off a bit of a storm here! My question was purely a theoretical one as I've no intention of riding an illegal cycle on the road (although read on). I was just intrigued, as so many people I know are riding e-bikes on the road with 1000w+ unrestrcted motors and throttles. In fact, I would estimate that at least half the e-bikes on the road are illegal in some way or other! I did try derestricting the motor but didn't change the max assist speed which remains at 25kph. I gave it a go off-road and TBH I didn't notice much difference except sharper acceleration and shorter battery range by about 20%, although I suspect it may climb faster. Personally I would say it's not worth breaking the law for! I've re-restricted it to 250W which is fine for normal use. I have, however kept the throttle on for now. I've rarely used it but I electrified the bike as I'm recovering from a major heart attack and just occasionally I run out of 'oomph' and the use of the throttle allows me a break to recover when stopping and sitting down isn't an option. I find it strange that permitted e-scooters have a throttle but e-bikes aren't allowed them.

Re: Derestricting motor to 500w - will I notice much difference?

Posted: 24 Sep 2020, 10:33am
by the snail
Rob Archer wrote:I find it strange that permitted e-scooters have a throttle but e-bikes aren't allowed them.

Throttles aren't illegal, but it has to pedal-activated, not just twist and go (apart from 'walk assist' mode).