# Electric Bicycle 60kph possible?



## mattW (Sep 14, 2007)

Not on the road at least, the limit (at least in NSW) is for a 200W system, which sucks. Anything over than an you can get done for driving an unregistered vehicle and even fined if you don't have a motorbike licence. It is a ridiculous system.

Its not completely unreasonable that 1000W would be capable of those speeds. I have no experience with them but it sounds about right.


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## JohninCR (May 6, 2008)

michael30.06 said:


> Is it possible to power a mountainbike type frame with an electric motor up to a max speed of 60kph on flat surface possiblt tarmac with electric power not pedal assist? I have seen big claims for 1000w front hub motors as part of electric upgrade kits? Does anyone have experience with fast E Bicycles?


My e-bike with a front hub motor does almost 55kph (34mph) with me on it, and I weigh 110kg. It goes faster with lighter riders, but probably not quite 60kph. Stated wattage is really meaningless with hub motors, and it takes high voltage to get up to the high speeds. eg Mine is wound for torque and was listed as 500W & 36V. For the speeds I'm getting, my batteries at full charge top out at 83-84 volts and on take-offs and hills I'm pumping well over 2kw through the motor. The maximum my controller can take is 85 volts, otherwise I'd bump it 96 volts and definitely do 60kph on the flats.

While my bike is fun, I need better hill climbing and I'd like a little better acceleration. To get there, I'm adding a geared hub motor on the rear, which is much better for acceleration and hills. I'm also going to swap out the front hub for a motor rated at 350W, but is essentially the same motor as mine, just wound for a slightly higher Kv (rpm/volt), and therefore has a higher top speed, probably above 60kph. 

This planned 2wd setup should get me to where I want until I construct a bike whose frame, brakes, suspension and tires can handle higher speeds. Once you get much above 30kph, brakes and torque arms (for the motor axle of a hub motor) become significant safety considerations that I can't stress enough, especially with a front hub motor. If it comes out of the dropouts at speed, it's not just falling off a bike. It's a serious accident that can get you killed.

If you're talking about those 1kw kits on Ebay, the numbers look good, though you'll likely need to go to a higher voltage for a real 60kph. My guy who designs controllers say it's just BS and is likely nothing more than the motor I have. I have heard a lot of complaints about Golden motors regarding delivery and customer service. Good or not, I don't know, but $600 or so including shipping seems too high to me, especially when you still have to buy batteries.

Don't forget the torque arms.

John


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## elevatorguy (Jul 26, 2007)

I have gone 66kph on a converted mountain bike but not on a flat, was a lot scary with the tires and brakes that were standard equipment on the bike. I know in the states it would be a big legal problem as it would be in excess of the 30 kph limit for motor assisted bikes


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## michael30.06 (May 22, 2008)

Thanks for the VERY helpful replies. So I now know it's possible if I get a controller that can handle the extra voltage and spend more money on the battery pack than on an expensive motor sold as 1000w. OK now to look dumb infront of everyone again what are torque arms. And is their a wheel mounting system safer than drop outs. 
I am quite keen on this idea especially with the hub motor as they look so stock on a MTB. My commute to work is about 30ks one way but with about 80% bike paths so road time will be minimal and if I don't draw attention with excessive speed on the road I should be fine. Do any of you have pictures of your set uo or specific recomendations about companies to deal with.


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## JohninCR (May 6, 2008)

Michael,

Everyone was a noob at some point. You're showing your smarts by asking stuff in these forums where there's a wealth of free info, which is so much better than the school of hard knocks going it alone.

If you ever had a bike with a coaster brake, it had a torque arm going from the rear axle connecting to the frame a few inches away from axle via a loop of metal around the frame tube secured by a bolt. This is needed with coaster brakes because the torque from braking has to be transferred to the frame of the bike or the hub would just spin in the dropout. A coaster brake is the only time any pedal bike gets any twisting torque applied to the axle, so dropouts simply aren't designed for anything other than to prevent the wheel from falling off.

Hub motors typically have a 12mm axle with flat sections that slide into the 10mm dropout. This holds the axle stationary forcing the motor shell to spin around it. While the torque at the tire and the ground isn't very high, at the 6mm radius it is hundreds of foot pounds, with only 1mm of the relatively thin metal making up the dropout to keep the axle from spinning. If the axle spins in the dropout, the least that will happen is some of the cables get twisted and break inside the hub motor (a major pain to fix), and the worst would be a face plant into the pavement from the axle spinning and climbing right out of the dropout. Imagine riding along and the front wheel just jumps right off.

The issue is easily and cheaply addressed by using a 10mm open ended wrench slid over the flats on the motor axle, and secured to the frame with a couple of hose clamps. Nice stainless steel torque arms can be purchased for about $20. I have a welding machine, so I just reinforce the dropouts with a piece of 1/4" steel plate on each dropout.

On my aluminum bike with a front hub, I had some torque arms on both sides made using some very strong but quite thin stainless steel. I didn't get 5 meters on my first ride before the axle spun, snapping both aluminum alloy dropouts like they were nothing. The stainless didn't give, it cut a grooves in the axle, allowing it to spin, but at least they held the motor on. 

I made new dropouts using 1/4" plate that I welded to some steel tubing that slides right over the front shocks like prosthetic legs. Any bikes I put a front motor on from now on will get the same treatment, whack off the dropouts and use a prosthetic sleeve to secure Frankenstein dropouts. I have no interest in putt-putting around at 30kph, so with performance it really becomes mandatory.

Sorry about the book for a post, but I think it's an important safety topic to be quite thorough, and this is coming from a guy who doesn't even wear a biking helmet, so it must be pretty darn critical.

John


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## michael30.06 (May 22, 2008)

Thanks for the answers. I am not sure what a coaster break is but I get the idea. Do you have any pictures of the prosthetic front forks. Loosing the front wheel at 45mph sounds painful and sudden!


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## EnergyOfOne (Jul 23, 2008)

How about 100kph  

This is Worth a Look See! The need for speed 

lucky this bike didn't break or they might have been up for a Darwin award.

http://www.youtube.com/watch?v=sGTB_uZdw0o&feature=related

I think they used a Briggs and Stratton E-Tek motor that are used on some high performance go-karts.

I am impressed with the E-Tek motor.

I am with you on this one Micheal a commuter too and from work costing almost zero dollars to run is definitely the go. 

I am interested in building or some one willing to share and build something like one of these concepts. It does not have to be anything like them as long as it fits the functional description set out below.

http://www.utipu.com/app/invited/id/6e8ae47a1f0e4b66a7c61b092293bf5b

 Has to look good, some of those concept designs would need improving for my liking. 

Full electric, at least 120km/hr, at least 200km per charge, 3hr charging fully enclosed from the weather - single person commutator to start with. 

Set up a development group and one day hopefully a manufacturing/development center in all the major city's in NZ. 

Give away all the plans to the wider community who join the development group so they can build from the specs make improvements at home if they wish all open source, share knowledge. 

Manufacture and sell cheap as chips to anyone in the development group to cover costs only. 

They will be the best sales people you could ever ask for with knowledge to burn as they will have already been involved with the progress.

Hey! if google can bring in 80 billion dollars revenue from a 'Free' search engine surly a global development group of millions and millions of developers world wide must be able to run rings around a measly search engine - Easy Peesy plough at least 80% of the earning back into the development group to bring on the next best thing since sliced bread. 
No stopping this train look out! 

Ops!!
Sorry! I had a blood rush, them animals just broke out of my conceptual zoo. Its good thing I wasn't riding that bike


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## prudencepu (Aug 29, 2008)

Hello, I'm from an electric vehicle company. My answer is yes, the speed can be 60km/h. The motor power should be 1000 watt, and the battery should be 40AH. Then the electric vehicle can still be the great one. The range can still be very far.


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## toppowerbattery (Aug 27, 2008)

Hello Michael , 

Yes, may be you can use LiFePO4 battery packs . These batteries can be discharged on a high rate . 

the websith is www.chinatoppower.com 

Some of the batteries packs are as following :


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## Doctorbass (Dec 12, 2008)

Hello guys, i'm new here.. i'm coming from the Endless sphere forum. I would like to show you my first EV (let's start with two wheels....)

I bought a dual suspensions dual disk brake mongoose bike with a special frame
that allow me to have enough room for 2.3kWh of battery and keeping a great low center of gravity for better handling.

My bike is doing 76.7kph(47mph) GPS.. at 100V using 432x 18650 lithium manganese cell. 









it can also pull more than 100lbs (really tested!)

i'm using a 5305 BLDC hub motor . I tested the torque and it can really pull two small dedan cars on the flat!!

I really love that creation! http://www.evalbum.com/1947

*I know a guy (STEVEO) from Ontario that is doing real92kph (57mph) !! driving a mooded crystalyte controller at 133VDC*

see the video: http://www.youtube.com/watch?v=PDzj2zosU2M&feature=channel_pagev


I'm preparing a new version of the crystalyte motor that will be serie/parallel config for every 3 phase with contactor.. so i'll get torque and speed.!!


I hope to share fun with you.. i'm also familliar with battery testS!


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