The Road Traffic Act defines a road simply as anywhere the public have access.

 

Combined with the right to roam legislation this could be taken as quite broad and cover a lot of places that are not tarmacced, that you couldn't possibly get to by car, are privately owned and which most people would think of as not part of the public highway.

 

Nick

 

PS. I'm still not convinced that 2 motors is automatically illegal for on road use. Two 250 W motors is the same power as one 500 W motor. There are bikes claiming legality with motors that could be described as more than 500 W, so it depends on the definition of power and whether you look at the system or the motor.

 

What is certain is that 2 motors is more likely to attract attention, and therefore more likely to be the test case.

Edited October 23, 200817 yr by Tiberius

It would seem to me that if there is some precedent whereby Wisper can fit a 'derestrict' button, it would be reasonable for others to do the same and have a bike which can operate in two modes. - I doubt that the Wisper unrestricted button has seen a court case yet though.

That's right Fecn, these derestrict facilities are described by suppliers as "off road" or for use on private land, and never claimed to be for on road use in the UK or EU countries. This amounts to a self declaration by the suppliers that they are illegal on road, in itself seriously damaging any defence raised.

 

The Bridleways Act of 1964 is quite clear in defining bicycles as accepted with all motor vehicles excluded, and even tricycles and other cycles are omitted from the inclusions. However, Sustrans has obtained a prosecution waver for tricycles from the DoT.

.

Edited October 23, 200817 yr by flecc

 

PS. I'm still not convinced that 2 motors is automatically illegal for on road use. Two 250 W motors is the same power as one 500 W motor. There are bikes claiming legality with motors that could be described as more than 500 W, so it depends on the definition of power and whether you look at the system or the motor.

 

What is certain is that 2 motors is more likely to attract attention, and therefore more likely to be the test case.

 

My point was never that two motors was automatically legal though Nick. As Jeremy observed, the Sparc hub drive has two 100 watt motors.

 

My point was that with the motors we commonly use, i.e. putting two motors each declared by the manufacturers as being at or close to the legal rating onto one bike, is illegal.

 

I don't think Jeremy's defence of being able to declare differently as the bike creator would stand up, and as said above, in the case where a rating declared kit motor is added to a rating declared e-bike to make it a two motor bike, I'm certain that defence would have no chance.

 

Again as I said above, the important factor to me is the risk involved for the person I'm advising, and for that reason alone I will continue to advise it's illegal until it's proven beyond doubt otherwise.

 

I'm also certain that a test case held at the right level with examination of the spirit of the law involved would have no option but to rule illegality, since the combined motor ratings are so obviously a breach of legislators clear intentions.

 

All a prosecutor has to do is state the UK and EU legislators intentions to keep these vehicles as bicycles and avoid them becoming motor vehicles, to which end they determined a speed limit and maximum continuous power rating. With that accepted by the court, the doubling of that rating with two motors can only be read as defiance of the law.

.

Out of interest, does anyone know how the Wisper 'derestrict' button works?

Is it volt or amp restriction?

.

If it's anything like the hub-motor bikes I have, it is likely that it simply disconnects the rotation sensor signal from the hub motor on it's way to the controller. That way, the controller never knows how fast the motor is going and won't cut the power.

All a prosecutor has to do is state the UK and EU legislators intentions to keep these vehicles as bicycles and avoid them becoming motor vehicles, to which end they determined a speed limit and maximum continuous power rating. With that accepted by the court, the doubling of that rating with two motors can only be read as defiance of the law.

.

 

I'm inclined to agree with that. I suspect that when the legislation was framed, "maximum continuous power" seemed to the legislators to be a convenient way to limit these bikes; probably not predicting the subsequent head scratching that would go on trying to work out exactly what that means

I'm inclined to agree with that. I suspect that when the legislation was framed, "maximum continuous power" seemed to the legislators to be a convenient way to limit these bikes; probably not predicting the subsequent head scratching that would go on trying to work out exactly what that means

 

Maximum Continuous Power sounded very much like an engineering term to me, so I did some digging on motor specs and definitions and found the following.

 

Maximum Coil Temperature (Tmax)- The temperature at which coil failure is expected due to excessive thermal expansion in the wire or insulation failure (which happens at around 150-170C).

 

Maximum Power Dissipation - The continuous power losses of the motor when when the coil is at Tmax and the ambient temperature is at 25C (i.e. how much waste heat the motor can get rid of without breaking down.... So if you feed 250W into an 80% efficient motor then you have 50W of heat to get rid of.)

 

Continuous Current (IcTMax) - The coil current corresponding to the maximum power dissipation of the motor. (i.e as much current as the motor can use indefinitely in 25C ambient air without melting itself.)

 

Maximum Continuous Power - Amps * Volts for the required amount of power to make the motor operate just below breaking point.

 

This seems to all make sense to me. The motor has to be able to get rid of all the waste heat or it melts its internals (such as when people decide to up the voltages). The point at where it can no longer get rid of it's waste heat is the absolute most work it can be made to do. When you're at that point and you try to give it more work, it melts... When you give it less work, it cools down... and it is all measured at 25C in still air. - That is the maximum continuous power that can be sustained.

 

Now.. for peak power, you can really make up any number you want.. but somehow or other you have to be able to get rid of the heat. You've got a couple of kg of copper coils which can soak up heat when it's cold and this takes care of stop/stall states. However, when the motor is stalled, all of the energy is being fed into it is dissipated as heat and 250W heats up 2KG of copper coils pretty rapidly.

 

Does that make sense to anyone except me?

Edited October 23, 200817 yr by Fecn

Maximum Continuous Power

 

Maximum Continuous Power sounded very much like an engineering term to me, so I did some digging on motor specs and definitions and found the following.

 

Maximum Coil Temperature (Tmax)- The temperature at which coil failure is expected due to excessive thermal expansion in the wire or insulation failure (which happens at around 150-170C).

 

Maximum Power Dissipation - The continuous power losses of the motor when when the coil is at Tmax and the ambient temperature is at 25C (i.e. how much waste heat the motor can get rid of without breaking down.... So if you feed 250W into an 80% efficient motor then you have 50W of heat to get rid of.)

 

Continuous Current (IcTMax) - The coil current corresponding to the maximum power dissipation of the motor. (i.e as much current as the motor can use indefinitely in 25C ambient air without melting itself.)

 

Maximum Continuous Power - Amps * Volts for the required amount of power to make the motor operate just below breaking point.

 

This seems to all make sense to me. The motor has to be able to get rid of all the waste heat or it melts its internals (such as when people decide to up the voltages). The point at where it can no longer get rid of it's waste heat is the absolute most work it can be made to do. When you're at that point and you try to give it more work, it melts... When you give it less work, it cools down... and it is all measured at 25C in still air. - That is the maximum continuous power that can be sustained.

 

Now.. for peak power, you can really make up any number you want.. but somehow or other you have to be able to get rid of the heat. You've got a couple of kg of copper coils which can soak up heat when it's cold and this takes care of stop/stall states. However, when the motor is stalled, all of the energy is being fed into it is dissipated as heat and 250W heats up 2KG of copper coils pretty rapidly.

 

Does that make sense to anyone except me?

 

 

I do not think it is an engineering term, rather a political one and therefore devoid of any meaningful definition. Hence none of the manufacturers or retailers knowing where they stand. Normal service as usual from the politicians, which is what keeps the lawyers in business

 

Iain

It is in this instance a political term, but not one to keep lawyers in business this time.

 

Quite simply, in any test case on using two 200 watt rated motors when the limit is 200 watts total, the term does not have to be defined, it only being sufficient to demonstrate that the limit has been exceeded, regardless of the meaning of the limit. That's fundamental to my argument in this thread, the fact that it's an easily read legal matter and in no way a technical one.

 

The manufacturers/suppliers have stated that the motor(s) are 200 watts each, so two of them break the law. No definitions are necessary since the manufacturers/suppliers have predefined the rating(s).

.

Are we not overlooking the point? If you have two motors you can out run the plod, and never get caught......he he.

Maximum Continuous Power sounded very much like an engineering term to me, so I did some digging on motor specs and definitions and found the following.

 

Maximum Coil Temperature (Tmax)- The temperature at which coil failure is expected due to excessive thermal expansion in the wire or insulation failure (which happens at around 150-170C).

 

Maximum Power Dissipation - The continuous power losses of the motor when when the coil is at Tmax and the ambient temperature is at 25C (i.e. how much waste heat the motor can get rid of without breaking down.... So if you feed 250W into an 80% efficient motor then you have 50W of heat to get rid of.)

 

Continuous Current (IcTMax) - The coil current corresponding to the maximum power dissipation of the motor. (i.e as much current as the motor can use indefinitely in 25C ambient air without melting itself.)

 

Maximum Continuous Power - Amps * Volts for the required amount of power to make the motor operate just below breaking point.

 

This seems to all make sense to me. The motor has to be able to get rid of all the waste heat or it melts its internals (such as when people decide to up the voltages). The point at where it can no longer get rid of it's waste heat is the absolute most work it can be made to do. When you're at that point and you try to give it more work, it melts... When you give it less work, it cools down... and it is all measured at 25C in still air. - That is the maximum continuous power that can be sustained.

 

Now.. for peak power, you can really make up any number you want.. but somehow or other you have to be able to get rid of the heat. You've got a couple of kg of copper coils which can soak up heat when it's cold and this takes care of stop/stall states. However, when the motor is stalled, all of the energy is being fed into it is dissipated as heat and 250W heats up 2KG of copper coils pretty rapidly.

 

Does that make sense to anyone except me?

 

Yes, that is about right although I believe that the rating is for output rather than input power. It is about how much heat the motor can dissipate and so prevent overheating.

 

De-rating a petrol engine is fairly easy as it is rated at maximum power, but I am not sure how this could be done practically for a motor where the rating is for continuous power; other than perhaps adding some insulation . In fact others have done the opposite, drilling holes in their hub motor to increase heat loss and so increase the motor rating.

Fecn,

 

You are right. What the motor itself will have is a maximum continuous current rating.

 

That will translate into a range of maximum continuous power ratings depending on the application and the assumptions made.

 

If the manufacturer declares a power rating, then it will be on the basis of one set of assumptions about how it is to be used. The user of the motor could legitimately say that he was operating it under different conditions and then declare a power rating that was higher or lower than the motor manufacturer.

 

In fact, the proper engineering approach would be that the motor manufacturer refuses to declare a power rating, but does declare enough information for the motor user (ie bike manufacturer) to calculate a power rating for that particular application.

 

Nick

Edited October 24, 200817 yr by Tiberius

 

In fact, the proper engineering approach would be that the motor manufacturer refuses to declare a power rating, but does declare enough information for the motor user (ie bike manufacturer) to calculate a power rating for that particular application.

 

Nick

 

One alternative though is the Panasonic one, where motor, all electronics and battery are a fully integrated single unit in which case they can fix the rating.

.

Ignoring the legal side of this proposed project, if someone does get round to building a two motor e-bike, won't it be so heavy that most of the extra power would show only a minor increase in performance.

There would be the extra weight of a motor, controller, cables, throttle, etc., and probably an extra battery. This could be quite a handful to ride and corner with, then stopping it would also need careful consideration.

 

Would it not be much easier and cheaper to build a completely illegal bike in the first place with a single high power motor, then remove any stickers or labels from the motor so nobody has a clue what you are riding:eek:

 

J:) hn

 

Would it not be much easier and cheaper to build a completely illegal bike in the first place with a single high power motor, then remove any stickers or labels from the motor so nobody has a clue what you are riding:eek:

 

J:) hn

 

I agree John, though there is an attraction in a two Tongxin Nano motor bike, relatively light, free rolling and silent. One would have to be adapted to rear derailleur though.

 

With their very small size coupled with the silence, they would scarcely be noticed.

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I agree John, though there is an attraction in a two Tongxin Nano motor bike, relatively light, free rolling and silent. One would have to be adapted to rear derailleur though.

 

With their very small size coupled with the silence, they would scarcely be noticed.

.

 

Or Tony, a second Torq1 front motor fitted to your T radical? You have alreday done the hard bit.

 

J:) hn

The thought had momentarily passed my mind John, but it would make a bit more noise and be fairly obvious if only from the performance. The weight would be a bit much too as you've said, needing two eZee batteries as well as the two motors it would be heading into old Powabyke territory.

 

In fact the T bike doesn't get much use as I'm quite happy with the Q bike's performance and capabilities.

.

In fact the T bike doesn't get much use as I'm quite happy with the Q bike's performance and capabilities.

.

 

Does this mean you might retire the T bike and put it out to grass;)

 

J:) hn

It'll get summer pleasure use John, it was never intended or equipped for bad weather of course. It's laid up in the garage now where it spent last winter.

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Tony,

 

I think your T bike is one of the best thought out and engineered hub motor e-bikes around:cool: It would be nice if Ezee took on some of your ideas and put them into a production bike.

 

J:) hn

John, the only controversial point in your post above would be 'one of'!

 

Unfortunately putting a the Tongxin in a rear wheel with decent gearing would be a challenge. They do a threaded motor but it is centred on the axle (possibly needs to be because of their two-part axle). This, and limited axle length means that it would only work with a very narrow freewheel - perhaps a 3-speed. When I put a 7-speed on mine there was hardly any axle showing out the end!

 

The wire comes out of the non-freewheel side so someone with the right engineering skills might be able to lengthen the axle but I'm not aware of anyone having done it. Maybe it would be as simple as taking the motor apart and replacing that side of the axle with a longer one - but I know little of the innards of the motor so can't judge how feasible that would be.

 

Frank

Point taken Frank. It is almost an insult to say Flecc's T radical is anything other than THE BEST My excuse, ......I am but a mere mortal:(

 

J:) hn

Maybe I should look at a 9-speed hub (no way I'm paying for a Rohloff at those prices) for the back wheel to get a bit of extra range out of the gears?

I found that reducing the gearing on my Wisper helped a lot with hills, I rarely used the top gears so didn't miss them.

 

The wire comes out of the non-freewheel side so someone with the right engineering skills might be able to lengthen the axle but I'm not aware of anyone having done it.

 

Frank

 

It can be done Frank, there's almost 22 mm internal diameter on the inner multi freewheels so an extender is possible. As you may know I had to have strength extension on both the Q and T bikes for that same short and weak spindle reason, the T bike one being spindle threaded as well.

.