When I switched it on it was about 10 minutes faster ! Yes, I just wanted to see how much "motor drag" affected it when ridden unpowered

That's what I hoped. I thought for a minute that you were going nuts!

What a shame we are never likely to see two teams of pedants in wigs fight it out!

 

Indeed.

 

But in retrospect, I was forgetting how readily some are prepared to lie to the Police etc, as in;

 

Policeman: "did you deliberately set the cut off speed above the legal limit ?"

 

Deceitful cyclist: "No officer, it must have been an imperfection on my part"

Loads more to think about, thanks. In short, the consensus seems to be that there's not much off-the-shelf that will glide along up to 25 km/h and ride like a non e-bike above that.

 

The discussion on battery life was useful, although I hope that's not the norm. Whilst I'd like a longer battery life than 3 years, I'd not be devastated if it gave up at that point--by then I'd know if I was going to use the bike regularly and what I really wanted from one.

 

I'm reluctant to go down the conversion route due to the time and knowledge required as this would turn it into much more of A Project and I'm sure to get something that didn't fit or wasn't compatible. Whilst I'm reasonably good at technical stuff, I have pretty much no experience of modern bike maintenance--I had a good look at my current bike, and the some of the teeth on the chainring look quite worn--so it probably needs replaced. Furthermore, it's always made a slight clunking sound in top gear--the front derailer seems to rub against the chain when I put push down (but not when turning the pedals by hand off the ground), and fiddling with the indexing doesn't seem to fix it. The chain's never been replaced either and the bikes about 6 years old (though seldom used). In short--maybe 15 years ago before I had kids, I'd have taken this on, but I don't want to add another project to my list of things I'll never get round to...

 

I think I need to take some test rides to see how things feel--the nearest dedicated ebike shop is about 50 miles from me, but I'll try and nip up over the next few weeks. Also gives me time to see if I can get work to sign up to a cycle to work scheme.

 

Faro and Metroneer look good, I'll keep them in mind. I'm also reconsidering the Camino--anyone any experience of its motor drag? Also, is it really legal for it to have a throttle that works without continuously pedalling?

You don't have to continually pedal to use the throttle but you have to rotate the crank a bit every 20 seconds or so to keep the throttle activated.

When I converted my wife's folding bike , I had a little 9 mile test circuit. Before I did the conversion it was taking me around 40 minutes. After the conversion (1.6 kg akm-75 + Woosh 36v 10ah bag battery 1.8 kg) I tried the same circuit unpowered and it took 27 seconds longer (3 seconds per mile !)

 

3 seconds per mile isn't much as shown with the AKM , it is perfectly rideable should delivery power fail.

The same ride with a std 5.1 ratio geared hub would take more effort and sap ones energy.

Likewise the same with a BBS vs TSDZ mid drive, riding a BBS unpowered is one experience I would not want to put to the test again. Did it once when I exceeded the range of my 14.5ah battery , the 15 odd miles ride home was knackering .

Likewise the same with a BBS vs TSDZ mid drive, riding a BBS unpowered is one experience I would not want to put to the test again. Did it once when I exceeded the range of my 14.5ah battery , the 15 odd miles ride home was knackering .

 

Yeah, you need minotaur legs to pedal an unpowered BBS01B for any length of time, I'm still growing mine. I can do sprints over cutoff speed, and those sprints are lengthening. But if the OP stuck to 25kph or less, that commute with hill mentioned, would be easy with a large battery and a programmable BBS01B, but not all are.

 

 

Loads more to think about, thanks. In short, the consensus seems to be that there's not much off-the-shelf that will glide along up to 25 km/h and ride like a non e-bike above that.

 

The discussion on battery life was useful, although I hope that's not the norm. Whilst I'd like a longer battery life than 3 years, I'd not be devastated if it gave up at that point--by then I'd know if I was going to use the bike regularly and what I really wanted from one.

 

I'm reluctant to go down the conversion route due to the time and knowledge required as this would turn it into much more of A Project and I'm sure to get something that didn't fit or wasn't compatible. Whilst I'm reasonably good at technical stuff, I have pretty much no experience of modern bike maintenance--I had a good look at my current bike, and the some of the teeth on the chainring look quite worn--so it probably needs replaced. Furthermore, it's always made a slight clunking sound in top gear--the front derailer seems to rub against the chain when I put push down (but not when turning the pedals by hand off the ground), and fiddling with the indexing doesn't seem to fix it. The chain's never been replaced either and the bikes about 6 years old (though seldom used). In short--maybe 15 years ago before I had kids, I'd have taken this on, but I don't want to add another project to my list of things I'll never get round to...

 

I think I need to take some test rides to see how things feel--the nearest dedicated ebike shop is about 50 miles from me, but I'll try and nip up over the next few weeks. Also gives me time to see if I can get work to sign up to a cycle to work scheme.

 

Faro and Metroneer look good, I'll keep them in mind. I'm also reconsidering the Camino--anyone any experience of its motor drag? Also, is it really legal for it to have a throttle that works without continuously pedalling?

 

Some conversion kits are easier to install than others (by way of example, see BBS02 Dahon conversion video below), and there's plenty of advice available from forum members for hub motor conversions. The right conversion with low motor drag (not the BBS01B) will do what you need.

 

 

Edited October 13, 20241 yr by guerney

The same ride with a std 5.1 ratio geared hub would take more effort and sap ones energy.

 

Yes, the tbk-74 (rebadged akm-75) has a 12.6 reduction ratio on the 328 rpm version (suitable for 20" wheels)

3 seconds per mile isn't much as shown with the AKM , it is perfectly rideable should delivery power fail.

The same ride with a std 5.1 ratio geared hub would take more effort and sap ones energy.

Likewise the same with a BBS vs TSDZ mid drive, riding a BBS unpowered is one experience I would not want to put to the test again. Did it once when I exceeded the range of my 14.5ah battery , the 15 odd miles ride home was knackering .

That's right. There is no drag from an AKM motor because the clutch is between the hub and motor, so only the hub rotates when freewheeling. Most of the other motors have the clutch between the reduction gears and the rotor, so the internal gears still rotate when freewheeling. The difference is minimal.

 

Basically, an AKM motor is exactly the same as a normal hub, except that the bearings are slightly larger. The difference you feel is from the extra mass of the hub, which increases both the rotational inertia of the wheel, and the whole mass of the motor increases the bike's linear inertia. Those two things together make the bike a bit more sluggish for acceleration, but on the positive side, it makes you faster downhill, especially if you're a light rider and/or have a light bike.

Like [mention=39093]Peter.Bridge[/mention] above i can ride out on my bike with no noticeable drag from the hub drive.

However when switching off the power mid ride i do feel an increase in the resistance to pedalling beyond that felt when starting off without any power?

 

My limited understanding of electricity and magnetic fields suggests its al in my head, but my legs tell me otherwise..?????

Like [mention=39093]Peter.Bridge[/mention] above i can ride out on my bike with no noticeable drag from the hub drive.

However when switching off the power mid ride i do feel an increase in the resistance to pedalling beyond that felt when starting off without any power?

 

My limited understanding of electricity and magnetic fields suggests its al in my head, but my legs tell me otherwise..?????

The magnets don't come into it because they're disengaged when pedalling without power. The only way they can make a differences is when your clutch is stuck, which does happen from time to time, so always worth checking.

 

I've been riding mainly hub-motored ebikes of every type for the last 14 years. I've never experienced any noticeable drag from any motor in any circumstances, except when the clutch was stuck, and, obviously, direct drive motors, which are terrible.

The magnets don't come into it because they're disengaged when pedalling without power. The only way they can make a differences is when your clutch is stuck, which does happen from time to time, so always worth checking.

 

I've been riding mainly hub-motored ebikes of every type for the last 14 years. I've never experienced any noticeable drag from any motor in any circumstances, except when the clutch was stuck, and, obviously, direct drive motors, which are terrible.

99% sure there is no stuck clutch as the difference if any is slight and the following day when i ride off without power (most trips start off downslope from here) any sign of resistance has gone.. BTW i do generally turn the bike on to check battery level when starting off but turn it off again once sufficient remaining power has been confirmed.

 

SO all in my head- as i suspected Cheers.

99% sure there is no stuck clutch as the difference if any is slight and the following day when i ride off without power (most trips start off downslope from here) any sign of resistance has gone.. BTW i do generally turn the bike on to check battery level when starting off but turn it off again once sufficient remaining power has been confirmed.

 

SO all in my head- as i suspected Cheers.

Find a hill. Start from stationary at a known point. Freewheel down the hill to see what maximum speed you get. Repeat with whatever you think it takes to make the drag, then you can see if there's a difference. Obviously, do the tests on consecutive runs in the same conditions wearing the same clothes, etc.