Obviously these bike designers aren`t getting it .In early Engineering training I was led to believe that a shock load was twice the normal load .This must apply to chains as well .

Obviously these bike designers aren`t getting it .In early Engineering training I was led to believe that a shock load was twice the normal load .This must apply to chains as well .

 

There us an instance of chains suffering with crank drive in the Bosch unit. When first introduced there were reports in Germany of chains being wrecked in about three months due to the unit's power. Since this problem subsequently disappeared it's assumed they detuned it slightly after early production.

 

Other than that the only reported transmission problem specific to crank drives on production bikes was with the original version of the Giant Lafree Comfort model which used the generally rather poor Shimano 4 speed hub gear. A number of these failed and Shimano withdrew that gear hub and have never replaced it, Giant using the tough SRAM P5 five speed hub instead for the Comfort model and the Nexus 3 and SRAM S7 on other Lafree versions. Since that problem was specific to one gear hub design only, it cannot be blamed on the Panasonic crank drive fitted to the Lafree series.

Just received the latest issue 92 of A to B magazine, which has reviews of two new simply specified Chinese made e-bikes under the Momentum brand. They have some interesting features and A to B are clearly impressed.

 

The Tonaro review is of the Eagle model and it is distinctly critical in a number of ways, bike weight, battery weight, battery warranty, power control, gear and chain problems and range being singled out in particular for criticism.

 

I have to say that, as ever, I differ quite strongly from many of the views they express, especially on the Momentum bikes. The issue 92 hasn't reached the free-to-read online website yet, but should do so shortly.

 

I got an email yesterday to say the free-to-read issue 92 of A to B was available - you just register to access it.

 

I was amused read in the review this characterisation of the Tonaro Eagle and its riders,

As these machines are aimed firmly at lazy folk, and market research indicates that people of this kind don’t even like to turn pedals, let alone apply any force, there is also a twistgrip, which delivers power on demand.

Despite my increasing appreciation of the availability higher assist settings on my Agattu, and indeed my more frequent use of them, I hate the electric moped like feel of the crudely controlled Tonaro type of bike. I would always choose a Panasonic or similar motor with the motor power controlled by means of a proportional torque measuring device.

Lazy folk!

 

Many people use e-assist bikes when the alternative given their physical condition, means that they would never even consider using a bicycle.

 

I myself am an insulin dependant diabetic and without e-assist, there is no way I would have ever considered commuting daily the 10 mile round trip via a bicycle.

 

The use of these kinds of words/statements do little to promote ebikes to the public

 

Jerry

Edited October 31, 201213 yr by jerrysimon

When first introduced there were reports in Germany of chains being wrecked in about three months due to the unit's power. Since this problem subsequently disappeared it's assumed they detuned it slightly after early production.

 

Or fitted a 'better' quality chain..

I hate the electric moped like feel of the crudely controlled Tonaro type of bike. I would always choose a Panasonic or similar motor with the motor power controlled by means of a proportional torque measuring device.

 

 

Where as I much prefer the system on my bike which means that as long as I'm turning the pedals the motor gives me full power. I don't see the point in the bike deciding for me how much power it will give me.

 

If I decide I want to go slower I can always adjust the PAS setting. Torque sensors are not for me.

I hate the electric moped like feel of the crudely controlled Tonaro type of bike. I would always choose a Panasonic or similar motor with the motor power controlled by means of a proportional torque measuring device.

 

You'll get no argument from me on that score sir! Torque sensors are not unique to crank-driven bikes of course and I was pleasantly surprised by how well the power delivery operates on some hub-motor bikes I rode not long ago.

 

Nonetheless, I still have a preference for crank-drive and I think Bosch have it about right, especially on those bikes where the manufacturer has placed the battery inside the the triangle. The extended wheelbase to accommodate a battery behind the seatpost just seems so unnecessary to me and I don't care for those mounted on the rear rack either.

 

Indalo

Despite my increasing appreciation of the availability higher assist settings on my Agattu, and indeed my more frequent use of them, I hate the electric moped like feel of the crudely controlled Tonaro type of bike. I would always choose a Panasonic or similar motor with the motor power controlled by means of a proportional torque measuring device.

 

I like the simple throttle control on my Powabyke X6. Although it does have a moped feel if you're letting the motor do most of the work you can also use it as a subtle (or not so subtle) top-up to your own efforts. If I'm pedaling hard then normally it's because I'm pushing myself so I don't want much assistance, so the assistance I want isn't proportion to the torque of the pedals.

 

With the throttle I can unconsciously adjust the level of assistance to match the way I'm feeling at that moment, for example I might start a hill trying to see if I can climb it on my own, then part way up realise that the answer is "no" and use the throttle to get just enough help to keep the challenge within my reach.

The extended wheelbase to accommodate a battery behind the seatpost just seems so unnecessary to me .

 

Indalo

 

It does have the advantage of better integration of battery and unit though, with no flying power lead to get damaged and exposed cable connections to suffer water damage. From that point of view Bosch have stepped backwards, and have also made provision for step-through impossible with that battery placing.

 

I don't think the tiny length increase of the rear of seat tube battery makes any material difference on a road bike, especially since most designs tweak the frame angles to minimise the additional length.

...

With the throttle I can unconsciously adjust the level of assistance to match the way I'm feeling at that moment, for example I might start a hill trying to see if I can climb it on my own, then part way up realise that the answer is "no" and use the throttle to get just enough help to keep the challenge within my reach.

 

I did not like the range of throttle controlled bikes which I tried out earlier this year. (see http://www.pedelecs.co.uk/forum/electric-bicycles/11816-redbridge-testing-hubs-v-cranks.html#post141596 ). Some throttles were extremely crude, and I then wrote,

 

I am not a fan of having one hand clasped to a throttle as seemed needed on some of the hub motor systems without a proportional torque sensing control - but that is a criticism of the control system rather than the hub motor as such. I like to be able to give prolonged signals with either arm. Also I did not like the way some of the hub control system carried on pushing for about a second after the the throttle was released- but I suppose you might learn to live with that.

 

So what happens with my Kalkhoff Agattu, with the proportional torque control, when I hit one of the hills which you describe? I often ride on minimum assist - I provide 2/3 of the power, and the motor provides 1/3. That way I get some good quality exercise taking into consideration my age and fitness. When the slope increases and I realise that I will soon start to slow, with my left thumb I can give the assistance-increase button either one press (which gives 1/2 power from me and 1/2 from the motor) or two presses (which gives 1/3 power from me and 2/3 from the motor). That is up to a fourfold increase in motor power if my power remains constant, and this can get me up all but the steepest of hills without increase of my effort. Actually if the hill is not too long I may also increase my own pedalling power, because I can look forward to some recovery after cresting the summit.

It does have the advantage of better integration of battery and unit though, with no flying power lead to get damaged and exposed cable connections to suffer water damage. From that point of view Bosch have stepped backwards, and have also made provision for step-through impossible with that battery placing.

 

I don't think the tiny length increase of the rear of seat tube battery makes any material difference on a road bike, especially since most designs tweak the frame angles to minimise the additional length.

 

I have to take issue Flecc. While I agree that positioning a battery on the forward downtube creates a difficulty with regard to a step-thru facility, it does not preclude those who wish to enjoy Bosch power from so doing. It simply means a rack-mounted battery is required as on AVE and Hercules models for example.

 

In respect of the increased wheelbase, that varies from make to make. The effect on me is that my Gazelle simply does not fit my motorhome bike rack whereas my Cannondale fits perfectly. In the case of the Gazelle, it's too heavy anyway, even minus the battery. Both my MTBs and my Dawes road bike also fit the rack easily.

 

Any Bosch-powered bike coming in at 20Kgs or under with central battery placement would suit me perfectly.

 

Indalo

I have to take issue Flecc. While I agree that positioning a battery on the forward downtube creates a difficulty with regard to a step-thru facility, it does not preclude those who wish to enjoy Bosch power from so doing. It simply means a rack-mounted battery is required as on AVE and Hercules models for example.

 

Indalo

 

I did take that into account though, saying "with that battery placing". I was aware of the rack mounted batteries on their step-throughs, but that makes the system even less integrated and more vulnerable to water/connection problems.

 

I agree that the rear of seat tube battery isn't suitable for e-bikes intended to be carried behind narrower vehicles, nor is it as suitable for very rough off-road terrain where the wheelbase length is more critical. But the vast majority of e-bikes are never subject to either of those and for that majority I think the integrated low-mounted rear of seat tube battery makes a lot of sense.

 

 

 

So what happens with my Kalkhoff Agattu, with the proportional torque control, when I hit one of the hills which you describe? I often ride on minimum assist - I provide 2/3 of the power, and the motor provides 1/3. That way I get some good quality exercise taking into consideration my age and fitness. When the slope increases and I realise that I will soon start to slow, with my left thumb I can give the assistance-increase button either one press (which gives 1/2 power from me and 1/2 from the motor) or two presses (which gives 1/3 power from me and 2/3 from the motor). That is up to a fourfold increase in motor power if my power remains constant, and this can get me up all but the steepest of hills without increase of my effort. Actually if the hill is not too long I may also increase my own pedalling power, because I can look forward to some recovery after cresting the summit.

 

.... but you get that surging instead when you press hard on the pedal going up hills, which as well as being a bit uncomfortable, is also a bit inneficient and you have to stop if your legs get tired and can't pedal any more.. Every system has advantages and disadvantages. I've not yet found one that I couldn't get on with. The 36v Panasonic scared me when it clunked as I put my foot on tyhe pedal, but that was because I wasn't expecting it. I guess you soon get used to any idiosycrasies, when you own a bike.

the Panasonic "clunk" is always being discussed on German pedelec

I've no doubt that the Bosch has a smoother power delivery and is probably a more torque system. Having had years to study the Panasonic drive I should hope they'd have improved on it.

 

That said I wouldn't like folk to think that the Panasonic system is in any way agricultural. Occasionally during slow hill climbing you can feel a faint pulsing and if you put a lot of pressure on the pedal at a standstill it will try to pull away.

 

These are minor issues however and the general ride quality of my Pro Connect is great. After 2500 miles I'm more than happy with the bike, well balanced and reassuring at any speed and the latest batteries have a great range.

 

Couldn't imagine anyone not enjoying the ride.

I like my Panasnic PCs but I'm under no illusion that there are better systems out there now. It still works really well though and it's best point is the reliability and the very natural way it rides without the power on...really extends the range.

the Panasonic "clunk" is always being discussed on German pedelec

 

Eddieo,

Which thread? I dont know German, but I tried searching for Panasonic Knacken and found this thread:

"Knackgeräusch" beim Panasonic Mittelmotor Kalkhoff Agattu XXL

Reading the results of a Google "translation" makes me wonder if they are discussing the "tick" or rather faint click that is sometimes observed on these units, eg the discussion here at http://www.pedelecs.co.uk/forum/electric-bicycles/6379-panasonic-kalkhoff-crank-play.html.

 

I have ridden on 3 Panasonic Kalkhoff Agattus and I also had a one week test ride of an Agattu with the new Impulse motor. None of these has emitted anything like a clunk from the motor. The worst you get is a loud click from the hub gear if you try to change gear without freewheeling for half a second or so.

 

I have occasionally heard faint tick apparently synchronised with the pedal rotation, but it does not seem to indicate a significant mechanical problem, and it is quiet enough not to be annoying given the woosh of the tyres on the road surface, and the sound of the wind in one's ears.

The way in which the power delivery is controlled on the Panasonic units means it's inevitable there will be some pulsing, it's meant to work that way, tracking the muscle effort and adding to it. There are some people who just cannot get on with this system, I think because their physiology doesn't naturally reconcile the mismatch of effort input and response output, For everybody this is momentarily disconcerting when they first try the system, particularly when a light press on a pedal produces a fast getaway, but the majority quickly adapt to it.

 

Hub motor systems don't have this problem since they are clearly a separate power source divorced from personal effort, particularly when throttle controlled, so there's no physiological balance disturbance.

Just to make it clear, the clunk I experienced on the 36v Panosonic unit was like a pre-engagement. When I rested my foot on the pedal there was some mechanical activity in the motor even though I didn't move - like when you engage first gear on a car before you set off and there's a small amount of clutch drag. I don't remember this happening on the 26v Panasonic.

So what happens with my Kalkhoff Agattu, with the proportional torque control, when I hit one of the hills which you describe? I often ride on minimum assist - I provide 2/3 of the power, and the motor provides 1/3. That way I get some good quality exercise taking into consideration my age and fitness. When the slope increases and I realise that I will soon start to slow, with my left thumb I can give the assistance-increase button either one press (which gives 1/2 power from me and 1/2 from the motor) or two presses (which gives 1/3 power from me and 2/3 from the motor). That is up to a fourfold increase in motor power if my power remains constant, and this can get me up all but the steepest of hills without increase of my effort. Actually if the hill is not too long I may also increase my own pedalling power, because I can look forward to some recovery after cresting the summit.

 

Not having completely independent control of the amount of assistance I get when climbing wouldn't suit my riding style. I take having fine moment-by-moment control of the motor for granted, and having just three modes which influence but don't in themselves determine the level of assistance would feel cumbersome unless I changed the way I rode.

 

You're right that the loss of power when you make hand signals does feel cumbersome, I've resigned myself to having to do without any help when I'm turning right, but for me that is offset by the level of control I have over the motor when I'm climbing.

 

I suppose that any control system will feel cumbersome or crude if it doesn't match your riding style.

Just to make it clear, the clunk I experienced on the 36v Panosonic unit was like a pre-engagement. When I rested my foot on the pedal there was some mechanical activity in the motor even though I didn't move - like when you engage first gear on a car before you set off and there's a small amount of clutch drag. I don't remember this happening on the 26v Panasonic.

 

It sounds like they've added a form of start control to deal with the increased power on that unit Dave. The usual kick-off the mark with some pedal pressure could be even more disconcerting for many with the higher power, so there may be a torque sensing pressure point to get past before the motor is permitted to start driving the transmission.

 

A bit crude if so. I doubt the power pulsing system that the Panasonic unit uses is really suitable for high powers, it was certainly smoothest of all on the original unit which was lower powered and had no high power mode. Interestingly member 10mph mainly uses the low power Eco mode so would also get the smoothest results for most of his riding.