Is 250w enough power for modest speed up steep hills

[MartinC]

.........all I can think of is some form of hub gear but I haven’t done the maths to see what (overall) reduction might result, and hub gears can be pricey.

Yes it's hard for Vantage to find a solution that doesn't involve changing lots of stuff. I don't know of a hub gear that's guaranteed to take the torque from a powerful 1:1 input. Even going the non legal route means changing the motor unit.

[Vantage]

Ah, well that problem doesn't actually exist for me anymore as I did indeed go the illegal route not long after that tour. The current motor is rated for 750w. It can go to 1200w but anything over 700w and the pawls in the freehub start slipping making some not so very nice noises. It is limited to 15.5mph too.
I have tested it with a full load going up a 20% hill and it quite happily pulls the load without overheating.
I just don't understand what reasons the rule makers had for limiting motors to such a meagre wattage. It's probably perfectly fine for a flat country without winds etc but for everywhere else, it's just stupid.
For what it's worth, the 42t sprocket is part of an off the shelf cassette I bought specifically to reduce the chances of burning out the previous motor. It still got hot on many climbs.

[MartinC]

........I just don't understand what reasons the rule makers had for limiting motors to such a meagre wattage. It's probably perfectly fine for a flat country without winds etc but for everywhere else, it's just stupid.....

I think the rationale, IMO sensible, is to keep unregulated vehicles used in public spaces to about the same kinetic energy level (i.e. risk to others) as we've traditionally had with pedal cycles.

Before there was a trade off, a fit 12 stone racing snake on an 8kg bike might maintain 30mph (and still can) but a 23 stone human on a BSO or a tourist with a heavy load couldn't but with an EAPC they could now. We sensibly have all sorts of regulations about more powerful vehicles which we as cyclists and vulnerable road users rely on. There's long been a category of power assisted bicycles and anybody who needs or wants more power than a legal EAPC can simply get a legal electric moped - here's a 4000w one https://urbanebikes.com/collections/ele ... -soco-cp-x

There is a trade off, I fully expect there to be a backlash as the number of illegal EAPC's multiplies and incidents occur. There will then be pressure to regulate all EAPC's, and even all cycles, with compulsory insurance, licencing, cycle/rider testing and all the associated bureaucracy (eyesight, medical conditions, blood alcohol levels etc.). I personally don't have much sympathy for those prepared to help bring this about. YMMV.

[Carlton green]

........I just don't understand what reasons the rule makers had for limiting motors to such a meagre wattage. It's probably perfectly fine for a flat country without winds etc but for everywhere else, it's just stupid.....

I think the rationale, IMO sensible, is to keep unregulated vehicles used in public spaces to about the same kinetic energy level (i.e. risk to others) as we've traditionally had with pedal cycles.

Before there was a trade off, a fit 12 stone racing snake on an 8kg bike might maintain 30mph (and still can) but a 23 stone human on a BSO or a tourist with a heavy load couldn't but with an EAPC they could now. We sensibly have all sorts of regulations about more powerful vehicles which we as cyclists and vulnerable road users rely on. There's long been a category of power assisted bicycles and anybody who needs or wants more power than a legal EAPC can simply get a legal electric moped - here's a 4000w one https://urbanebikes.com/collections/ele ... -soco-cp-x

There is a trade off, I fully expect there to be a backlash as the number of illegal EAPC's multiplies and incidents occur. There will then be pressure to regulate all EAPC's, and even all cycles, with compulsory insurance, licencing, cycle/rider testing and all the associated bureaucracy (eyesight, medical conditions, blood alcohol levels etc.). I personally don't have much sympathy for those prepared to help bring this about. YMMV.

^^ What he said. Indeed, and I know it’s harsh, I’d support the confiscation and crushing of illegal cycles are such devices put the rest of us at risk of the fate that MartinC describes. I wonder what platforms list such items for sale to the general public? I think that they should be liable under UK law for the products listed and sold to the general public, and no defence that it’ll be used on none public land.

[thirdcrank]

Anybody with a long memory (can remember QEll's coronation as though it was yesterday but not what they had for breakfast) will surely remember an earlier incarnation of mopeds. The comic even had a spell when it was Cycling and Mopeds. Mopeds of that era were heavy, low-geared "pushbikes" with a (sub 50cc?) motor. The main point being that a reasonably fit cyclist could leave one standing. Along come the inscrutable Japanese and the same regulations, interpreted quite differently, produced high-revving lightweight motorbikes with pedals which were merely to ensure compliance

[horizon]

I just don't understand what reasons the rule makers had for limiting motors to such a meagre wattage. It's probably perfectly fine for a flat country without winds etc but for everywhere else, it's just stupid.

They aren't limited (AIUI). It is only that you must wear a helmet, be insured etc. In fact, you could argue it the other way and marvel at how generous the rule makers have been in allowing a bicycle with a motor still to be defined as a bicycle.

[Vantage]

To still be classed as a bicycle they are limited. Over those limits and they're classed as pedelecs, mopeds and motorbikes which as you state do require a helmet and the legal documents etc. Therein lies the problem that the rider is then further restricted in where they can be ridden and additional costs mount up in the form of insurance etc. I ride a bike to be free of all that carry on.
These bikes should also cater for those less able to ride an unpowered bike. As CJ is finding out with his wife, those people have not been considered.
I don't mind complying with rules. As long as said rules are reasonable and well thought out.

[Nearholmer]

I’ve asked this innumerable times before when all this ‘I want the moped laws liberalised’ stuff has come up previously, and nobody has responded, but I suppose it’s worth another crack:

1) in what ways do you suggest the law should be amended to meet your wishes? (That’s the easy question); and,

2) what practical, workable, and likely to be enforced measures do you propose to prevent whatever you propose in (1) leading to unintended negative consequences including, but not limited to, the increased use of vehicles of power >250W on shared-use paths including bridleways? (That’s very likely to be s harder one to answer).

[stodd]

I’d support the confiscation and crushing of illegal cycles are such devices put the rest of us at risk of the fate that MartinC describes.

I think crushing is unnecessary if the bikes are safe and legal as electric mopeds. (Many may not be, they'll have dodgy batteries and maybe other faults.) The police could fit plates and resell them at fairly low price, but requiring proof of license, insurance etc from the buyer. That would raise general awareness of the limitations of pedelecs and the opportunities for legal use of more powerful machines.

The original owner might even be given 10% of the profit of such sales (taken off the fines for driving without insurance, etc etc)

[CJ]

42T chainwheel pulling a 42T sprocket and 700c wheels.
42t chainwheel is the smallest that can be fitted without causing serious chain bending (mid drive motor).
If you can lower that gearing without having to spend serious money then you're a better mechanic than I.
Buying an entire new bike because some twits came up with a stupidly low power limit isn't an option for many.

Sorry for the delay, but as you didn't quote me I didn't get a prompt. From your answers to some subsequent replies it sounds like you have a Bafang mid-drive. As it happens I've recently electrified my wife's 700C wheeled bike with a BBS01B, the 250W model. I was able to fit slightly smaller chainring than you have: that is the 40 tooth Lekkie 'Bling-Ring', which (for £140) comes with a lower-profile gearbox cover, so the teeth can nevertheless be offset to maintain a perfect chainline with the centre of the cassette. And the latter has a MUCH bigger bottom sprocket than yours. It's a Shimano Deore 11-speed cassette, with sprockets from 11 down to 51 teeth. This did entail lashing out on a new mech and shifter (the previous system was 2x10), but a new 1x mech would've been wanted anyway, and the result is well worth it. With this motor and gears from 98 down to 21 inches, Helen can now easily ride up any of Matlock's hills, some as steep as 1:4, and hasn't even used the top power level yet.

Total cost of the conversion - which includes a 468Wh carrier-mounted battery - was under £1000 by the way.

[CJ]

I’ve asked this innumerable times before when all this ‘I want the moped laws liberalised’ stuff has come up previously, and nobody has responded, but I suppose it’s worth another crack:

1) in what ways do you suggest the law should be amended to meet your wishes? (That’s the easy question); and,

2) what practical, workable, and likely to be enforced measures do you propose to prevent whatever you propose in (1) leading to unintended negative consequences including, but not limited to, the increased use of vehicles of power >250W on shared-use paths including bridleways? (That’s very likely to be s harder one to answer).

Although I have suggested this, as an infinitely preferable alternative to upsetting the approximate parity and tolerant relationship between legal e-bikers and muscle-bikers, I am not the one who wants the moped laws liberalised. It is up to those who want more powerful motors and higher assisted speed, to tell us what needs to change about the UK's moped regulations, to enable speed-pedelecs to become as popular here as they are in Germany and Switzerland for example.

I do not know what our Dept of Transport did to restrict mopeds back in the 1970s (or was it 80s?). I was not then and never will be a motorcyclist. But I did observe that mopeds rapidly disappeared from our streets, whilst remaining a commonplace part of the transport scene elsewhere in Europe. As a first move, I'd suggest studying how our European neighbours are managing the situation. They're obvoiusly getting a lot of things right.

[CJ]

These bikes should also cater for those less able to ride an unpowered bike. As CJ is finding out with his wife, those people have not been considered.
I don't mind complying with rules. As long as said rules are reasonable and well thought out.

What I'm finding out, by the way, is that the rules DO consider the need for start-assist. This feature is now permitted and found on an increasing number of ready-made E-bikes. My problem seems to be that it has not (yet) been catered for in Bafang's firmware
- I guess because of this Chinese manufacturer's focus on the gung-ho American market. But I'm nevertheless working on the implementation a 6kmph limited throttle, which IS legal.

[Vantage]

1) in what ways do you suggest the law should be amended to meet your wishes? (That’s the easy question); and,

2) what practical, workable, and likely to be enforced measures do you propose to prevent whatever you propose in (1) leading to unintended negative consequences including, but not limited to, the increased use of vehicles of power >250W on shared-use paths including bridleways? (That’s very likely to be s harder one to answer).

1) That one isn't all that easy to answer really. Not without affecting question 2.
I don't know about off the shelf ebikes but my first Bafang bbso1b 250w motor often exceeded 600w on the display. I personally think 500w as a continuous max could cover pretty much any hill on a loaded bike, whether it be shopping or touring gear. But that 500w would mean a peak power limit of 1000+w if my thinking is correct.
If there was a peak power limit, 750w I think would suffice. In my limited experience thats enough for some silly steep climbs. It's what I've set my Bafang bbs02b to. That particular motor however has twice the torque as the bbs01b. Cleverer people than I would need to figure that one out.
2) A difficult one indeed. I honestly can't see any reasonable method other than the (slightly amended for power rating) laws we have currently to address this. The sale of such kits/bikes being restricted would go a long way to fixing the problem of silly power ebikes. At the very least, I'd suggest that a licence and relevent documentation be required prior to the purchase of vehicles requiring such documents etc. If I understand it correctly, any Tom, Rick and Henrietta can buy a car etc without a licence etc which imo is utter madness.

[Vantage]

Sorry for the delay, but as you didn't quote me I didn't get a prompt. From your answers to some subsequent replies it sounds like you have a Bafang mid-drive. As it happens I've recently electrified my wife's 700C wheeled bike with a BBS01B, the 250W model. I was able to fit slightly smaller chainring than you have: that is the 40 tooth Lekkie 'Bling-Ring', which (for £140) comes with a lower-profile gearbox cover, so the teeth can nevertheless be offset to maintain a perfect chainline with the centre of the cassette. And the latter has a MUCH bigger bottom sprocket than yours. It's a Shimano Deore 11-speed cassette, with sprockets from 11 down to 51 teeth. This did entail lashing out on a new mech and shifter (the previous system was 2x10), but a new 1x mech would've been wanted anyway, and the result is well worth it. With this motor and gears from 98 down to 21 inches, Helen can now easily ride up any of Matlock's hills, some as steep as 1:4, and hasn't even used the top power level yet.

Total cost of the conversion - which includes a 468Wh carrier-mounted battery - was under £1000 by the way.

I did look at the lekkie rings but £140 for a chainring to me at least is taking the urine. The 42t I have currently isn't bafangs own but a Chinese knock off that cost about £50. Again with the cassette, there are indeed much bigger ringed models out there but the cost I found was in my opinion, silly. My current one was about £50 and even that left a bitter taste at the price.

[Nearholmer]

I think the rationale, IMO sensible, is to keep unregulated vehicles used in public spaces to about the same kinetic energy level (i.e. risk to others) as we've traditionally had with pedal cycles.

Which seems to me a very sensible, and logical way to look at it. That, or something based around the sustainable power output of an ordinary person (not a super-athlete) riding a bike.

A difficult one indeed. I honestly can't see any reasonable method other than the (slightly amended for power rating) laws we have currently to address this.

That’s the rub. I think you’re effectively saying the same thing as others of us: that once a vehicle gets above the ‘kinetic energy level of a pedal cycle’, or some similar formulation based around human power output, regulation of some form or another is needed to control a number of risks, mainly risks around misuse, and use by naive youngsters.

The present regulations are, I assume, intended to achieve that, and if they were enforced or enforceable they probably would achieve it, but as I understand things from previous posts you aren’t at all keen on the present regulations, because they make the sort of vehicle you need a ‘motorcycle’, with all the registration, insurance, license-holding, and helmet-wearing that entails.

Cleft stick?