First Electric Bike Choice

[Bad Company]

Id really recommend going to a proper electric bike shop and getting some expert advice. I used the Electric Bike Shop (Harrogate) recently and they were great, other branches are available.

That said I'm really not keen on that specialized. As you've noticed the range is a lot poorer, and the lack of removable battery limits where you can charge it. It also doesn't have a display as standard, just a small light to indicate power level.

The Cube is great, I was looking at those myself along with something else called a Haibike Trekking. Big comfy tyres, suspension and removable batteries. Yes they are heavier but they are very well equipped.

The Cube Kathmandu is about £5-600 more than the Haibike Trekking. I haven’t tried the Haibike yet but the specs seem very similar.

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[ebikeerwidnes]

You certainly have to disregard the "personal import" and DIY kit type ebikes when considering battery safety

Not sure about the power as my extensive survey (i.e. just me) of 4 bikes says that the mid drive Bosch gave the save sort of power feel (i.e. no hard data) going up hills as the previous Suntour hub drive and Bafang hub drive (long story in there reagrding why so many in a short time!!!)

all were standard UK road legal bikes so quite low power

I didn;t actually choose to have a mid drive - again, a long story - but ended up with it and I have been very pleased with it
however, I do worry about failures to critical edrive components - there is certainly a lot of chatter on the forums about Bosch being a "Oh it's failed - OK you can buy a new one" type repair strategy

but so far, after over 4 years of use the only problems have been normal bikey things plus unusually high chain and gear wear
plus a few issues with bolts that I blame Raleigh for (4 have broken - all the same size - possibly a bad batch??)

Would I choose the same bike again if it got stolen??

dunno - I might look around but I wouldn;t be biased for or against hub drive

 

[ebikeerwidnes]

Just thought of another point
prompted by the "I bought and electric bike thread"

The other day I went for a ride even though it was windy. I knew that the battery was only showing 3 out of 5 bars - and that the first bar takes ages to disappear and then they get quicker as it goes down - but it seemed like enough

Anyway - on the way home I ran out of charge and had to pedal home unassisted - yes I know - shock horror etc
I presume the wind on the way out had used up more charge than normal - naturally there was no great tailwind on the way home - you know how that goes!

Anyway I pedalled home OK - mostly in a gear lower than usual - hence a bit slower and lasted just fine
(until I got home when I explained to my wife - who naturally rolled her eyes and went to sit down at which point I had an asthma attack - my asthma is weird like that but whatever!)

Anyway - I have heard from some people that their ebike has a significant resistance to pedalling when there is no battery charge left - or if the battery is dismounted.
To the point where the bike is difficult to ride as just an ordinary bike.

I have never tried one that seems like that - but as I have heard it I thought it was worth mentioning
might be worth trying riding it with no battery - or the assistance switched off - before buying - there will always come a point where you run out of charge and have to pedal it properly!

 

[bonzobanana]

Just thought of another point
prompted by the "I bought and electric bike thread"

The other day I went for a ride even though it was windy. I knew that the battery was only showing 3 out of 5 bars - and that the first bar takes ages to disappear and then they get quicker as it goes down - but it seemed like enough

Anyway - on the way home I ran out of charge and had to pedal home unassisted - yes I know - shock horror etc
I presume the wind on the way out had used up more charge than normal - naturally there was no great tailwind on the way home - you know how that goes!

Anyway I pedalled home OK - mostly in a gear lower than usual - hence a bit slower and lasted just fine
(until I got home when I explained to my wife - who naturally rolled her eyes and went to sit down at which point I had an asthma attack - my asthma is weird like that but whatever!)

Anyway - I have heard from some people that their ebike has a significant resistance to pedalling when there is no battery charge left - or if the battery is dismounted.
To the point where the bike is difficult to ride as just an ordinary bike.

I have never tried one that seems like that - but as I have heard it I thought it was worth mentioning
might be worth trying riding it with no battery - or the assistance switched off - before buying - there will always come a point where you run out of charge and have to pedal it properly!

That's interesting as it sounds like some mid-drive motors like Bosch are injecting a small amount of current into the motor to negate the resistance in the motor. They probably borrowed this from direct drive hub motors which have a little resistance and a small injection of current by the controller can give a very good freewheel effect on some models. There is a video from Grin I think explaining how its done. I guess the best way to tell what your mid-drive ebike has is try it with the motor off with both the charged battery fitted and with it removed and see if you can sense any difference when peddling without the motor on, if there is no difference and no obvious drag I assume it has a well designed clutch mechanism. I've never thought the drag of direct drive motor is that bad. Yes you can feel it but it is very marginal. There is a demonstration of it at 2 minutes 30 seconds in on this video;


View: https://www.youtube.com/watch?v=mAKfv28kAkc


I feel the drag is worth it too to get regen braking so you can brake without wear on your pads and get a small recharge into the battery too to extend your range.

 

[ebikeerwidnes]

That's interesting as it sounds like some mid-drive motors like Bosch are injecting a small amount of current into the motor to negate the resistance in the motor. They probably borrowed this from direct drive hub motors which have a little resistance and a small injection of current by the controller can give a very good freewheel effect on some models. There is a video from Grin I think explaining how its done. I guess the best way to tell what your mid-drive ebike has is try it with the motor off with both the charged battery fitted and with it removed and see if you can sense any difference when peddling without the motor on, if there is no difference and no obvious drag I assume it has a well designed clutch mechanism. I've never thought the drag of direct drive motor is that bad. Yes you can feel it but it is very marginal. There is a demonstration of it at 2 minutes 30 seconds in on this video;


View: https://www.youtube.com/watch?v=mAKfv28kAkc


I feel the drag is worth it too to get regen braking so you can brake without wear on your pads and get a small recharge into the battery too to extend your range.

Some time ago I read an interesting article that went into a lot od detail I didn;t understand about how motors and generators work

The upshot was that it is easy to design an efficient motor
and it is easy to design an efficient generator and they are very similar
but they are not the same and an efficient motor will generator energy if spun - but it isn;t efficient and making it capable of doing so also reduces the efficiency of it as a motor

and the other way round

Hence - it said - you could make a motor that pumped energy back into the battery when you coasted or braked - but the charge gained was far less than the loss in efficiency lost in normal pedalling assist.
And the more you increased the charge you would gain - the less efficient you made the motor assist
to the extent that it was not worth trying to build a bike that did both
As the motor gets bigger and the vehicle gets heavier then the problems reduce - hence the use of hybrid cars works


AT least that was what it said

I have recently seen things that suggest that a couple of manufacturers might have overcome some of the problems in order to make an ebike that does regen under coasting
But I don;t know how well they work!

 

[bonzobanana]

Some time ago I read an interesting article that went into a lot od detail I didn;t understand about how motors and generators work

The upshot was that it is easy to design an efficient motor
and it is easy to design an efficient generator and they are very similar
but they are not the same and an efficient motor will generator energy if spun - but it isn;t efficient and making it capable of doing so also reduces the efficiency of it as a motor

and the other way round

Hence - it said - you could make a motor that pumped energy back into the battery when you coasted or braked - but the charge gained was far less than the loss in efficiency lost in normal pedalling assist.
And the more you increased the charge you would gain - the less efficient you made the motor assist
to the extent that it was not worth trying to build a bike that did both
As the motor gets bigger and the vehicle gets heavier then the problems reduce - hence the use of hybrid cars works


AT least that was what it said

I have recently seen things that suggest that a couple of manufacturers might have overcome some of the problems in order to make an ebike that does regen under coasting
But I don;t know how well they work!

A direct drive motor is the most efficient type of motor purely because of lack of internal gearing compared to geared hub motors and mid-drive motors but of course that isn't the final story its about application in a bicycle. Grin has some videos about motor efficiency and they are very long and complicated and basically they still have direct drive hub motors as the most efficient overall which I'm sure will surprise some people but that is really general use. The main inefficiency in ebikes is cadence sensors as they often supply power all the time even when the rider doesn't need it. A torque sensing bottom bracket monitors when the rider is working harder and assists only when the rider needs it and of course a throttle gives the rider full control so they can use it as much or as little as they like its completely their choice they can use it sparingly or as much as possible. Often people get confused about how power is applied and the efficiency of motor types. The basic violamart direct drive hub motor kits had a reputation for high battery consumption and low range but there were 2 issues, one was they were designed for throttles and so the supplied cadence sensor to Europe was very basic, as soon as you peddled it provided full power so was incredibly wasteful of power just like many basic ebikes either with geared hub motors or direct drive hub motors. The other factor was people didn't restrict them to the legal 15.5mph they unlocked them to 28mph and to get such a motor up to 28mph takes a phenomenal amount of power many times that of 15.5mph due to air resistance and motor inefficiency. One benefit of direct drive hub motors is the greater surface area and location means far more effective cooling and the lack of internal gearing means you can use liquids like stator aid to increase cooling even more. So even though direct drive motors can only offer from 25-40Nm torque they can offer that for the full ascent up a steep hill they don't have the thermal power throttling of small geared hub motors or mid-drive motors mostly. However thermal power throttling is also caused by the battery pack too as well as the motor and that can effect any motor type.

 

[Bad Company]

Think Mrs BC and I have decided on a pair of Cube Kathmandu Hybrid Pro 750’s. They’re heavy but at least the battery is removable which helps a bit and means we can charge them in the house leaving the bikes in the shed.a

A big plus for me was the satnav on the Bosch display which is hopefully a lot easier to use than my old Garmin Edge.

Anyone reckon we’re making the wrong decision?