Using illegal bikes

[flecc]

The problem with crank driven electric bikes is that there is a fixed relationship between the motor speed and the cadence in top gear. Thus at the top legal speed the cadence has to be reasonable enough to be comfortable and there isn't any way of altering that relationship without instantly making the bike technically illegal. With a hub motor, you can select as high a gear as you like independently of the top speed of the motor driving the hub.

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What I would like to know is how all those with crank motors such as Kalkhoffs and the like manage on slight downhills or with the wind behind them when by adding a bit of effort they could manage 25 mph except that the cadence is unsustainable. Does everybody use a smaller rear sprocket (and thus make the bike illegal) or just resign themselves to the sort of stately cycling I eventually got used to on the Giant?

Trevor

(Trek Cytronex)

Many Kalkhoff and other Panasonic system riders change the rear sprocket. Typically on the Kalkhoffs changing the 22 or 23 sprocket for an 18 to give assist to around 18 mph, but some go as far as a 16 tooth to get assist to just over 20 mph. The range suffers greatly then though, down from around 30 miles to as low as 18 miles.

The new Panasonic system can have it's cadence relationship changed by the way. The motor sprocket can be changed from 9 tooth to 11 tooth, altering the power cutoff cadence from 65 to 79 and the start of maximum power phase-down from 40 to 49 rpm.

That doesn't alter the cyclists gearing of course, but it does bring the illegality of power assist to higher speeds since the chain speed increases.
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[lemmy]

Does everybody use a smaller rear sprocket (and thus make the bike illegal) or just resign themselves to the sort of stately cycling I eventually got used to on the Giant

Personally, I just accept it. I can pedal up to about 20mph on the flat but generally go about 18mph.

I'm cycling in London, though, so average speeds are governed by traffic lights, pedestrian crossings and junctions more than actual speed. I'd imagine that in the rush hour the average speeds of a Ferrari, Honda Fireblade and any e-bike with whatever power and gearing wouldn't be too different.

If I had a cross country route without major hills, a bit more average speed from a hub motor might be welcome, though as is pointed out an increase of a couple of miles an hour is more of a psychological boost than a real one, given that a great deal of the time yer actual 17mph, like 15mph, will be unobtainable.

 

[Alex728]

I think one important factor is at present most "illegal" bikes are being constructed by otherwise law abiding and peaceable folk in their middle years or older, who have decades of safe road usage on two and four wheels behind them. from what I have gathered here, obtaining the bits for a high power e-bike also involves a considerable amount of effort, skill and a willingness to deal fairly and honestly with people of many cultures and nationalities and wait for things to happen, something lacking in a lot of younger folk...

there might be more of a problem when younger folk in the more reckless teens and twenties start getting interested in e-bikes, and the equivalent of the "gary boy" culture emerges, but this could be 5 years to a decade or more away. I wouldn't discount it outright though..

interestingly there doesn't seem to be a problem with modified / overpowered e-bikes in other European nations either, although that might be also because its a lot easier to ride a small motorcycle there without such lunacy as putting them through CBT test and having it expire after 2 years!

 

[Old Timer]

Well I`ve managed to fit an old style front brake to my twin hub bike (took it from my wifes old bike rusting away) cleaned it up, fitted new brake blocks etc and it works. So, thats the brakes made legal.

So I now have two hubs on the bike, I rarely use them both at once only just a steep hill while I`m getting my strength back. So yes, I`m riding illegal but really only for health reasons so I`ll just have to plod along carefully around the country lanes and at the end of the day it`s not the crime of the century.

I do take the point that if/when the younger people get interested in E bikes and start to experiment then the authorities might well take more notice but at the sort of age that they can get things up and running I reckon they will opt for motorbikes or scooters.

Dave

 

[Alex728]

I do take the point that if/when the younger people get interested in E bikes and start to experiment then the authorities might well take more notice but at the sort of age that they can get things up and running I reckon they will opt for motorbikes or scooters.
Dave

this is already what happens (particularly in the Mid Suffolk area where I work) and there are of course many derestricted scooters/motorbikes or those "driven otherwise than in accordance with a license", or on expired CBTs etc (which all younger riders now have to take even for low powered machines) - but every so often the cops do tend to do operations to target these.

Especially as East Anglians are not particularly criminally minded but can be stubborn and if they disagree with what they consider to be a "pointless" law many simply tend to ignore it until its strongly enforced..

Also a lot of younger folk learn the hard way that its not a good idea to be too reckless on two wheels (my mechanic friend who is about 23 has been to 3 funerals already of his customers )

Their noise also means neighbours are more likely to complain to cops if they are ridden late at night! Also they have reg plates and thus can be picked up on APNR and their riders held more accountable for their actions.

The obvious problem I can see is with fast modified e-bikes other than lack of traceability is younger people will be more tempted to ride them on pavements and other unsuitable areas, which they wouldn't do on a scooter/moped for fear of being nicked..

Any rise in cycling as a whole is going to necessitate a rise in awareness of all bicycles and associated laws within the constabulary anyway (this is also mentioned in the London document about the plans for increasing cycling there).

 

[lemmy]

We can see the start of bad behaviour with electric vehicles not with the young but with the electric scooters that the disabled use.

Some of these people are a menace in supermarkets and on the pavement - they are supposed to be limited to walking pace but in fact some will do double that.

There is a particular woman round my way who has an aggressive notice on the front of her scooter to the effect of 'I have a right to be on this pavement so if I hit you, it's your problem'. She whistles around at way over walking pace and should be nicked, in my opinion.

Human nature is such that whatever speed is available to you, that is what you would like to use. The fact is that the majority of users of disability scooters use them at sensible speeds and are no problem to anyone. That applies to e-bike riders, too. It is the dumb minority who will soup up their e-bikes and use them irresponsibly who will provide a stick to beat the rest of us.

 

[tangent]

The new Panasonic system can have it's cadence relationship changed by the way. The motor sprocket can be changed from 9 tooth to 11 tooth, altering the power cutoff cadence from 65 to 79 and the start of maximum power phase-down from 40 to 49 rpm.

That doesn't alter the cyclists gearing of course, but it does bring the illegality of power assist to higher speeds since the chain speed increases.
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Fascinating! I was wondering if it was possible to change the cadence/power assistance relationship in some way, as my biggest complaint about the Panasonic system is the leisurely cadence cut off.

The bike I have just bought has the 7 speed hub with a as yet unmodified 21T sprocket. I think it cuts out around 17mph, but it is so quiet and smooth that it is very difficult to be precise. Would this mean that I could achieve a 22% increase in speed before the cut-off just by changing the motor sprocket?

 

[flecc]

Would this mean that I could achieve a 22% increase in speed before the cut-off just by changing the motor sprocket?

In motor assist speed and cadence yes, since the 11 tooth motor sprocket would drive the chain that much faster, and therefore the back wheel the same increase.

50cycles sometimes have the 11 tooth sprockets in stock and the details on changing it are on my website in this page.
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[Alex728]

We can see the start of bad behaviour with electric vehicles not with the young but with the electric scooters that the disabled use.

Some of these people are a menace in supermarkets and on the pavement - they are supposed to be limited to walking pace but in fact some will do double that.

There is a particular woman round my way who has an aggressive notice on the front of her scooter to the effect of 'I have a right to be on this pavement so if I hit you, it's your problem'. She whistles around at way over walking pace and should be nicked, in my opinion.

And round here she will be! Due to the ageing population of this region, this is a problem which has actually led to injury and even fatal collisions, the victims being from the same age groups (hmm, just like the gary boys and girls!) - so both Norfolk and Suffolk Constabulary are taking a strong interest in ensuring mobility scooters are responsibly ridden in this area..

 

[tangent]

This sounds a great option to me, better than changing the rear sprocket in many respects. I would prefer to tackle a hill in a lower gear, but on a high cadence and still have the motor assist rather than having to change up for the hill and slow the pedals. I love the Panasonic system, but this is the one aspect of it that has always felt wrong.

 

[Teejay]

Tangent. Indeed it is. See this link http://www.pedelecs.co.uk/forum/electric-bicycles/4432-using-11-tooth-motor-sprocket-agattu.html.

Beware of over-gearing though, as the motor only has limited power. Since then I've replaced the rear sprocket with a 20t one and it romps up the hills once more at the expense of a couple of mph of outright speed.

The gearing is still quite high enough to whizz down a gentle slope at 24 or so (quite legally as its way past assist speed) where conditions allow.