Panasonic/Kalkhoff crank play

[quilly21]

I recently purchased a new Kalkhoff Pro Connect LX from 50cycles,
I noticed that randomly it would develop a light metallic clunk when the left hand pedal reached the bottom of its travel, once this starts it is there for the rest of the journey. I looked closely to see if anything was loose and all I could find was horizontal travel in the pedal crank of about 1-2mm which when moved side to side resulted in a metallic clunk. I had only used the bike about six times at this point and contacted 50 cycles to see what they thought.
I was advised this was not normal and they promptly collected the bike, advising me that as it was brand new they would not strip it but fit a new motor.
In the meantime I purchased one of the Technicon Privilege bikes wiggle were selling for my wife, which is built in the same factory as the Kalkhoff and uses the same Panasonic drive unit.
When it came to having the bike returned from 50cycles I was told that they had looked at the new drive units in stock and they all had similar lateral travel in the pedal crank.
I was advised they had stripped the motor down and re-greased the bearings and could find nothing wrong.
Strangely the Technium has almost undetectable lateral movement and definitely no clunk.
Does anyone have any experience of this lateral pedal crank movement? And is this normal?
Due to illness I have not yet been able to test the Kalkhoff since its return, but hope to resume my commute next week.
I have been using the Technium in the meantime and it has been faultless.

 

[tillson]

I have checked my, very nearly, two year old Pro Connect and there is no movement as you have described.

 

[flecc]

Is it the crank loose on the pedal shaft and rocking on the taper fit, or does the pedal shaft itself move in and out a couple of mm?

Please let me know so I can advise further.
.

 

[styx]

Kalkhoff crank

Hi quilly 21
I am also experiencing this sensation of movement in the left crank of my agattu though mine seems to happen at the top of the pedal movement as the downward stroke begins it feels exactly like the movement you would get with a slightly loose crank so my first reaction was to tighten the crank bolt though this did not cure it.Following this I tried changing the crank and pedals and also made sure the motor fixing bolts were tight all to no avail.I can detect no movement in the shaft.The problem has been there since the bike was new and has not worsened .I am not familiar with the internal workings of the panasonic system and wondered if the slight clunk could be due the operation of some form of sensor clicking by which causes the impression of slight movement in the crank.

 

[quilly21]

Thanks for the response,
The pedals are tight on the crank it is a visible movement left to right of the crank you can see the shaft move in and out and if you push it makes a metallic clunk. I am particularly concerned about the disassembly and apparent re lubrication of the sealed bearings! on a unit which I have read in this forum is a non serviceable item. Particularly as I was advised this would not be done due to the fact it was a new bike. The movement is still the same on return as it was when sent.
In all other respects I am very happy with this bike, but would like to know whether I am being fobbed off with this.
I will see how it goes in the next few weeks and get back to the suppliers or manufactures if it is still faulty.

 

[overlander]

Please do keep us informed, as i am thinking of buying a new xxl. I can accept a fault, any mechanical device can fail. But if its an inbuilt fault thats a different matter. One of my pet hates is crank clunking noises drives me mad. Cannot believe that this is normal, should be interesting to see where this goes.

 

[flecc]

The pedal shaft is one piece, so if it moves in and out one side, it's moving in and out on both sides equally of course. There isn't normally any lateral movement, but that to some extent depends on bearing alignments and the assembly components. Here is the complete pedalshaft assembly:

The precision ballrace at 1 locates the whole assembly in the crankcase at the left of the unit. The needle rollers at left 4 sit within the freewheel pawl housing that surrounds the freewheel engagement pawls at number 3, and that freewheel pawl housing is shown below in two views:

On that sits the precision ballrace with it's external neoprene sealing ring that locates the right hand side of the pedal shaft. You can see therefore that the two location points are separate and not solidly linked, allowing some lateral pedalshaft movement in some circumstances. That will not do any harm. Your chainwheel sits on the splines at the right of that pawl housing, so is only connected to the pedalshaft through the pedal effort torque sensing drum.

To illustrate further, the photo below shows the initially stripped assembly, showing the one piece pedalshaft and the way in which the Pawl assembly engages the pedelec torque sensing drum via splines:

The next photo shows the torque sensing drum assembly stripped, showing how the amorphous alloy sleeve engages the chainwheel mounting pawl housing at the right and the pedal shaft in the photo above on the splines at the left hand side against it's precision bearing. Therefore the whole pedal force connects through the amorphous alloy sleeve from the pedalshaft left to the chainwheel mounting pawl housing on the right. This amorphous alloy sleeve floats across the splines at each end, it has to in order to work, so in some circumstances it can be heard as it moves under pedal force.

continued below:
.

 

[flecc]

Finally, in the photo below within the torque sensing drum you see the centre tapped coils that set up a magnetic field around the amorphous alloy sleeve.

When pedal force is exerted, the stresses in the amorphous alloy sleeve transmitted via it's roughened bands (arrowed in yellow in the previous photo above) set up minute fluctuations in the coil magnetic fields, changing the coil currents, and it's these changes which the unit senses to measure the pedal effort and determine the motor power to apply.

These photos are from my Panasonic support website , never under any circumstances strip your pedalshaft assembly in this complete manner.
.

 

[oriteroom]

Please do keep us informed...... One of my pet hates is crank clunking noises .......... Cannot believe that this is normal, should be interesting to see where this goes.

Me too - I hate any clicking/clunking from the crank. My recent worn chain caused a feeling like I was stirring porridge with my feet. As Overlander says ... keep us informed.

Flecc - what a fantastic breakdown of the internals of the crank.

Mike

 

[Tim]

When it came to having the bike returned from 50cycles I was told that they had looked at the new drive units in stock and they all had similar lateral travel in the pedal crank.

Hello, I have checked all the bikes on display in our shop here in Richmond, including two very heavily used bikes, but none of them have detectable lateral play in the crank, so I'm puzzled about why you were told this.

 

[overlander]

Hi Tim,

It would be good if you could clear this up as i really do like your bikes and your honest participation in this forum but to spend £1700 on a bike that clunks it not acceptable.

 

[quilly21]

Update

Thanks to Flecc and others for your replies.
To keep you updated further to Tim's reply and confirmation that this play is not normal, I was contacted by one of the directors of 50 cycles to advise this was not normal and that they were arranging to collect the bike and fit a new motor unit as originally suggested, it seems this should have been carried out in the first place. It does not appear to affect the bike and it was only because I was originally advised to return it that I did so. In all other respects I am very happy with the bike.
I will post an update when the bike is returned.

overlander,
If you are thinking of buying one of these LX machines I will write a review when I have it back, but feel free to ask any questions.
I tried at least 15 different electric bikes of different type and manufacture some over considerable distances, before deciding on this particular model, I had initially intended to buy the Pro connect S but felt the difference in price for performance was not justified over the LX.
I am using it to commute a round trip of 34 miles in hilly West Wales (although I have ended up mostly using the Technicon /agguta clone I bought for my wife while the LX has been attended to)

 

[flecc]

I don't suppose we'll ever get to know, but the most likely cause of this lateral play is an omitted circlip at original assembly. I've never come across a case of this over the years in either the old or new versions, but I suppose human error could always intrude once.
.

 

[Gregorio]

Hello. I have just purchased a Kalkhoff Pro Connect S and it has a similar problem. Please could you let me knopw how your resolved this.

Thanks.

 

[Gregorio]

Hello there. I wonder if you could help. I took delivery of a new pro connect S about two weeks ago and it has now developed some crnak movement and the front sprocket rocks as a result away from the vertical and there is a clunking when one pedals. I wondered whether the solution to this porblem is straightforward and would appreciate your expert advice.

Thanks.

 

[tillson]

Movement in the chain wheel is normal, it is supposed to do that. As for the clunk, check the motor mounting bolts are tight, check for play in the pedal cranks and also the pedals themselves.

 

[Gregorio]

Many thanks, Tillson. I think the motor unit maybe a bit loose. Having read a few threads I gather the bolts can be toghtened. However, I am not sure how to take the cowl off on the left handside of the bike as it seems to be securely atached and I don't want to damage anything.
If anyone knows which screw to remove and any tips for doing this I woul;d be grateful!

 

[Scatty]

Gregorio you should get them to pick it up & replace the bike remember 100% Satisfaction Gaurantee, Why fix it yourselve

 

[banbury frank]

Hi looking at the forum Panasonic have major problems with the motor drive

The unit is now old fashion

Don't try to fix it yourselves Just return the bike for a new one

and Buyers looking for crank drive should look at the NEW Bosch powered bikes

they have had teething troubles but thy have fixed them

Frank

 

[tillson]

Gregorio you should get them to pick it up & replace the bike remember 100% Satisfaction Gaurantee, Why fix it yourselve

Whilst I agree that a new and expensive bike like the Kalkhaoff should be free from defects and the components should last a long time, I think that a couple of loose bolts might be stretching the definition of a defect.

Gregorio, from memory, I think the LH cowling securing screws are in the battery well. Remove the chain guard and have a good look around, they should be fairly obvious. I can't get to my bike to have a look at the moment. This is a two minute job and if it is loose bolts, shouldn't require the bike to be sent back for a replacement.