Pro Connect Feels Rough

[tillson]

Also, I think I'm right that in changing cogs I can expect a reduction in the range I am able to achieve. I just hope the reduction is not too much.

Yes, changing from a 9 to 11 tooth motor sprocket will raise the speed at which the motor cuts out. (that is the speed the bike is travelling at, not the speed of the motor in rpm, if that makes sense) This will inevitably lead to a reduction in range.

 

[JamesC]

A few weeks ago I phoned 50C and talked to Jim about the problem.
He sent me a 11T & 41T as I suggested they might solve the problem having followed the comments on this site.
I have just got back from holiday to find the parts had arrived. I have cleaned the chain and fitted the 11T first to see how it went. It is much improved and the only problem appearing to be too much slack in the chain. I still wonder if the rear tensioner arm is doing its job!
Now should I fit the 41T or should I remove a couple of chain links. Any suggestions?

I would fit the 41T as the first step.

If the 41T fits fine within the existing chain length and gives a nice feel, then you will have lots of confidence about the chain length having been 2 links too long for the original 35T.

You will also have the opportunity to find out if the slightly revised battery range is Ok for you.

As discussed earlier, the 41T will have the better chain wrap on the sprockets which seems to be essential to handle the extra assistance available from this bike.

James

 

[flecc]

Yes, changing from a 9 to 11 tooth motor sprocket will raise the speed at which the motor cuts out. (that is the speed the bike is travelling at, not the speed of the motor in rpm, if that makes sense) This will inevitably lead to a reduction in range.

Unless you change the rear sprocket on a hub gear bike to correct the cutoff speed back to 15 mph.

With a derailleur bike you could change the top gear sprocket or whole cassette, or merely not use the highest gear(s), limiting yourself to the highest one that cuts assist speed at about 15 mph.

Those actions will keep the range the same.

 

[robelee]

If I use the 11t motor cog - does the rule still apply Flecc?

Rob

 

[flecc]

Yes Rob, you'll need to change the rear ratio by the amount of that front increase for the motor to work over the original range of speeds. I means increasing the rear sprocket used by around 22%, that's roughly one tooth increase for each five existing teeth.

 

[WALKERMAN]

QUOTE=JamesC;114008]I would fit the 41T as the first step.

If the 41T fits fine within the existing chain length and gives a nice feel, then you will have lots of confidence about the chain length having been 2 links too long for the original 35T.

You will also have the opportunity to find out if the slightly revised battery range is Ok for you.

As discussed earlier, the 41T will have the better chain wrap on the sprockets which seems to be essential to handle the extra assistance available from this bike.

James[/QUOTE]

I fitted the 41T this afternoon and gave it a quick try out. It seems fine and it has cancelled out the chain slackness.
I notice the chainring that I took off was showing wear on the front edge of each tooth in the form of a quite visible ridge. I have only done about 1500 miles on the bike so that seems odd.

 

[WALKERMAN]

I did my 14 mile commute today on my PC Disc with the 11T motor sprocket and the 41T chain wheel and it feels just fine. No noise, no pedal vibration and no loose chain.
Thanks to the guys on here for their invaluable help in resolving the problem and to 50C for supplying the parts for free and sending them out quickly.

 

[robelee]

Hi Walkerman,

Good for you in getting the parts free of charge. I emailed Scott of 50 Cycles to see if they would reimburse me - I can only hope!

Rob

 

[robelee]

Many thanks Scott,

Rob

 

[vaasa]

Seeing the service you have, I wish I had bought my PC from 50 cycles... I paid my chain-wheel and motor sprocket from my own pocket.
But being in Paris, France, I would encounter some difficulties when sending the bike back to repairs in case of issues

Anyway, I'm now very pleased with my PC LX. I've done about a 1000 miles since the change and it runs very smoothly as it should have been from the beginning. As I have a derailleur version with higher maintenance requirements, I thoroughly clean&degrease&lube my chain every 300-400 miles and change it once the chain wear indicator I have indicates me that I should do it. That should keep chain-wheel, motor-sprocket and all the cogs in a good running condition for a long time.

And btw, more I ride, more I start to like my PC. I might consider buying one after all (for my wife). New 36V 2012 lineup seems to be quite attractive. It is to be hoped that they have sorted out the problem with 9T motor sprocket by now

 

[banbury frank]

Hi

Good old support from 50 Cycles

Frank

 

[flecc]

Hi

Good old support from 50 Cycles

Frank

Indeed it is Frank, and they've just been awarded Kalkhoff's Distributor of the Year title, the second time they've won it.

And to affirm their worth, they have also been nominated as a finalist in the prestigious National Business Awards.

 

[robelee]

Hi Everyone,

I thought it only fair to write and say how fantastic my Pro Connect is now. Changing over to the two new cogs has made all the difference. I prefer the the new gear ratios and find the reduced range acceptable.

As I said in one of my earlier posts, my wife has a new Agattu and now manages to keep up and cover the same distance as me. Her usual average distance covered on a coventional bike was around the 12-15 mile mark. Now she's up to 30-35 average. We both find that we are pleasantly tired after one our rides - not knackered!

We are off in our motorhome for 3 weeks in September touring through Belgium, Luxembourg, Germany, Austria and perhaps Italy. We can't wait to explore some of the towns and villages along the way on our 'Kalkhoffs'.

We'll let you know how we got on when we return.

Rob and Lee

 

[JamesC]

I thought it only fair to write and say how fantastic my Pro Connect is now. Changing over to the two new cogs has made all the difference. I prefer the the new gear ratios and find the reduced range acceptable.

We are off in our motorhome for 3 weeks in September touring through Belgium, Luxembourg, Germany, Austria and perhaps Italy. We can't wait to explore some of the towns and villages along the way on our 'Kalkhoffs'.

Hi Rob
Good to hear that the bikes are going well.

Luxembourg is one of my favourite areas for cycling.
Beautiful, surfaced cycle paths through wonderful countryside.

Consider the small town of Berdorf which has excellent access onto the cycle network. Pop into any Tourist Office (most towns have one) and buy the map of the Luxembourg Cycle Network - very clear.

James

 

[robelee]

Thanks James,

We will do as you suggest. Years ago I visited Esch sur Sure, is that anywhere near where you suggest? Any other tips appreciated.

Rob

 

[JamesC]

Thanks James,

We will do as you suggest. Years ago I visited Esch sur Sure, is that anywhere near where you suggest? Any other tips appreciated.

Rob

Pretty much anywhere in Luxembourg is only a bike ride away, but no; Esch sur Sure is NW towards the Belgium border whilst Berdorf is east above Echternach on the German side. The cycle paths link most of the country.

If you are driving down through the German region of the Ardennes, just south of Bonn is the small town of Rheinbach. Ulli and Carmen Golla at Tri-Sporting-Golla carry good stocks of Panasonic parts (batteries, sprockets, tensioners etc) and are very knowledgeable on the various marques from Derby Cycles. Best to call them in advance rather than just turn up.

James

 

[NRG]

I thought I had more or less worked around the sprocket issue by reversing it on the motor shaft but it seems every now and then it comes back so today I decided to take some action and thin the teeth down.

I used one of those hand held band sanders, the thin one, used for various jobs like recessing door locks etc, any how to my surprise the sprockets are not as hard as I thought and it didn't take long to take about .1~.2mm off...

Result, back to smooth running with no snatching of the chain...

 

[flecc]

JamesC has been convinced that incorrect sprocket width has been the source of many of these problems and it seems he's right NRG. The difference he has mentioned to me in connection with 9/10 speed chains is about 0.2 mm of excess sprocket width, but I'm not sure what chain you have.