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Old 07-23-13, 05:44 PM   #1
sreten
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16" folding electric bike and speed versus 20" folder

Hi,

Great for hills but yesterday I simply breezed past one doing 17mph.
(18mph currently with 66 gear inches is my max flat no wind speed).

In the UK the law says the electric assist on an electric bike should shut
off by 15 mph, fine for hills, going up them or down, but on the flat ?

It was a no contest, on the flat the electric bikes not even geared
to do 15mph on its own (fair enough matching to the law) and it
probably pans out its simply not worth trying to go fast as the
assist shuts off, you are stuck with bimbling along or pedalling
like a demon on a bike with ~ 46 gear inches and a lot of weight.

rgds, sreten.

Electric bikes need to be a lot more fun than that ....

Last edited by sreten; 07-23-13 at 05:54 PM.
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Old 07-23-13, 06:22 PM   #2
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Maybe David Cameron is still mad about having his own bike nicked,

so sandbags things with that 15MPH rule so no one else can have fun.
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Old 07-23-13, 06:35 PM   #3
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Maybe David Cameron is still mad about having his own bike nicked,

so sandbags things with that 15MPH rule so no one else can have fun.
Maybe he is thinking of people who like to yell from passing cars but need time to think of something
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Old 07-23-13, 07:08 PM   #4
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Quote:
Originally Posted by sreten View Post
... UK the law says the electric assist on an electric bike should shut
off by 15 mph, fine for hills, going up them or down, but on the flat ?...
Initially I was taken aback a little with this law and wondered what the use would be aside from granny/gramps getting around at a decent pace with little effort but then I remembered the brutal headwinds I encountered on the Eastern coastline and through the Scottish Highlands when I was huffing to maintain 10mph... so yea I guess even a "governed" assist could be helpful. But then, do the UK "Officials" really monitor stuff like that? Around here <50cc scooters can be operated without a license and/or registration yet there are plenty of people riding vintage "big displacement" Vespas or modern 150cc scooters as though they fell under the 50cc restriction, because no cop checks unless the rider is exceeding 35mph (the <50cc speed limit). They think a scooter is a scooter and a scooter is a kid's toy.

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Old 07-24-13, 02:38 PM   #5
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Originally Posted by sreten View Post
Hi,

Great for hills but yesterday I simply breezed past one doing 17mph.
(18mph currently with 66 gear inches is my max flat no wind speed).

In the UK the law says the electric assist on an electric bike should shut
off by 15 mph, fine for hills, going up them or down, but on the flat ?

It was a no contest, on the flat the electric bikes not even geared
to do 15mph on its own (fair enough matching to the law) and it
probably pans out its simply not worth trying to go fast as the
assist shuts off, you are stuck with bimbling along or pedalling
like a demon on a bike with ~ 46 gear inches and a lot of weight.

rgds, sreten.

Electric bikes need to be a lot more fun than that ....
I've long been intrigued with the idea of electric bikes, as much for the promise they may hold as a means of transportation, as for what I might do with one.

I live in Seattle and the hills have discouraged me from riding at times. I can can climb the steepest hills, but I am the type that perspires easily and walking into a meeting, sweating heavily, isn't cool - even here. I have taken a conventional bike w/ 700 wheels on the bus, using the rack in front and then ridden back, but this isn't ideal. Sometimes the racks are full and when they are not, the mechanism for holding bikes in place clamps down over the front wheel in a way that is rough on fenders. Since I got a Brompton, that is what I use when I take the bus, so I can simply take it into the bus with me.

Lately I have been toying with the idea of adding an electric motor to my 700 wheeled bike. There is a simple 250W system sold locally that only increases weight by about 8 lbs for the hub motor, controller and LI batteries that have a range of about 10 miles (many variables). The system is designed to replace your current front wheel and comes with the hub motor laced to a rim of the specified size, complete with tire and tube, plus the electronics. As appropriate for the name of this system - the "Hilltopper" I would only use the motor going up hills and I would still pedal while doing so.

Back to your point, depending on one's purpose, 15 mph could be all that is needed. Limited speed systems seem to work pretty well in europe and asia. When I read about people using them here, the argument always seems to come up that we can go up to 750W in the us, more power is good, etc. There are some very cool electric bikes. Some are inspired by high speeds, but I like the designs that don't really look different from a regular bike, retain the qualities we love about bikes, are light weight, but provide juice if and when you need it. Like everything else - different people have different priorities. Higher speed can easily be achieved (perhaps not legally) but battery demands will generally increase significantly unless range is very limited.

I don't know if I'll ever go ahead with the electrification project, but my wife is very clear that she has absolutely no interest in doing so to her single, her brompton nor our tandem.
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Old 07-24-13, 02:39 PM   #6
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Originally Posted by BassNotBass View Post
But then, do the UK "Officials" really monitor stuff like that?
Hi,

Not really. They make the laws and check that new stuff for sale
abides by them. So most new electric bikes abide by them.

But it gets complicated very rapidly. In the US an electric bike can be as
fast as a moped (50cc) class. in the UK an electric bike that can do 15mph+
unassisted is a moped, and must be registered, taxed and insured, and
fulfil regulations for lighting, braking etc just like any moped / 50cc bike.

Electric mopeds are sold, but they look like any other
50cc moped, with no pedals, are an electric motorcycle.
(And has to be said very limp compared to a typical moped.)

The 15mph limit is relatively easy to build into the
control electronics of wheel motors. It is easy but
illegal to sell say 20" wheel electronics with 26".

Crank powered bikes are even more complicated.

There is always a way round the law, and you'd
be unlikely to be found out unless being silly.

But currently electric bikes in the UK are not much fun.
They are for those who ride but exercise very little.

Most who buy them don't modify them.

Of course there is an underground that does.

rgds, sreten.

Last edited by sreten; 07-24-13 at 02:42 PM.
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Old 07-24-13, 03:07 PM   #7
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Originally Posted by DoubleDiamonDog View Post
Back to your point, depending on one's purpose, 15 mph could be all that is needed.
Hi,

Well in the UK that is what they have decided. Simplest it basically fits in
with a cheap 6 speed 16" folder, that most can't pedal to 15mph, and on
the assist setting, which is the only useful one in a wheel powered electric
bike, it makes hills / headwinds a breeze but helps much less on the flat,
extending the battery life, it all makes common sense for a commuter.

It will notably improve acceleration, and speed on hills and headwinds,
and basically takes the really hard work out of getting around on a bike.

Still the maximum speeds of my folder and road bike downhill are 32mph.

Whilst I can see the common sense of the regulations they are somewhat
onerous on anyone wanting to build an electric bike that is simply more
fun everywhere than a pedal powered only bike, you simply can't build
one in the UK you can legally use on the roads. Well you can but as
said before its treated as moped, you can't build and sell one.

In the States you can, and I understand fit small petrol engines too
without it being classed as a motor vehicle. All I can say about the
latter with some of the US bike brake regulations, not a good idea.

rgds, sreten.

Last edited by sreten; 07-24-13 at 03:11 PM.
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Old 07-24-13, 03:49 PM   #8
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Originally Posted by sreten View Post

Still the maximum speeds of my folder and road bike downhill are 32mph.

rgds, sreten.
But couldn't a bike be geared differently, so that it could be pedaled and achieve speeds like you do, but electric power only supports speeds to 15 mpg? Or is does the law prohibit any bike with electric power from exceeding 15 mph? That would be discouraging.

If I did the little project I described above I would be able to climb at a faster rate than I currently can thanks to the added 250W (maybe really only 200ishW due to inefficiencies), but my speed on flats and downhill would not be effected by the added electrical system. Well, technically it may be infinitesimally slower on the flast and faster downhill due to the added 8lbs.
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Old 07-25-13, 11:59 AM   #9
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Originally Posted by DoubleDiamonDog View Post
But couldn't a bike be geared differently, so that it could be pedaled and achieve speeds like you do, but electric power only supports speeds to 15 mpg? Or is does the law prohibit any bike with electric power from exceeding 15 mph? That would be discouraging.

If I did the little project I described above I would be able to climb at a faster rate than I currently can thanks to the added 250W (maybe really only 200ishW due to inefficiencies), but my speed on flats and downhill would not be effected by the added electrical system. Well, technically it may be infinitesimally slower on the flast and faster downhill due to the added 8lbs.
Hi,

My point was when you point a bike down a hill you can easily get
to 30mph on anything, pedalling and gearing doesn't come into
it except on a fixie.

Yes the system you describe can take the edge off the hardest
parts of the journey. Such systems also exist for Bromptons.

FWIW bottom gear on my 20" is 33", my 700C road bike
40", but I can climb better on the road bike than the folder.

rgds, sreten.
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