Pro Connect Feels Rough

[flecc]

That's basically the situation vaasa, using a 41 tooth limits one to the 9 tooth motor sprocket for legality with 28" wheels and those hub gears.

At one time an enterprising company released some pressed steel spiders with Shimano hub gear inner fitting so that one could use chainrings from 24 teeth upwards on them, but I've been unable to locate them so they may no longer be available. One of those could have solved the problem, but only where the frame allowed the larger diameter at the rear, not all do readily.

 

[Patti]

Please look at what I wrote somewhere else (not quite sure how the site works). I had precisely that problem - ie grinding & something that sounds as if the gears aren't connecting properly. And it's only when the power is being used; when it's just me pedalling, everything is fine. I have just rung 50 cycles who said that it's the motor drive sprocket and they are sending me two new ones (in case one is useless like the one the bike came with - I have had it for less than 3 weeks)...

 

[flecc]

I've answered on your other thread entry Patti, asking what kind of gears you have, hub or derailleur.

 

[JamesC]

I apologise in advance if this post is a complete red herring, but I would be interested to hear about the thickness of the teeth on the Panasonic chainwheel when derailleur gears are used.

My experience is entirely with the earlier Kalkhoffs using Shimano hub gears, except unusually I have also changed my ProConnect over to a Rohloff hub gear.

Unlike the Nexus/Alfine hub sprockets, the Rohloff sprocket has narrower teeth and would normally run with a 3/32" chain compared to the 1/8" chain that we are used to on ProConnects and Agattus.

The Panasonic motor sprocket is thin and would be fine with a narrower chain, but the original 41T Panasonic chainwheel (supplied for hub gear bikes) has teeth that are 3mm thick - ideal to run in 1/8" chain, but too thick for 3/32" chain.

I imagine that the Kalkhoffs that are fitted with derailleur gears are using the narrow 3/32" chain.

What thickness have they used for the chainwheel teeth ?

I can imagine that if an original, thick chainwheel has been picked up in error, a narrow chain would cling to the chainwheel and be carried up too high to engage smoothly with the motor sprocket, using all of the available slack of a tension arrangement. This would cause slippage at the motor sprocket.

Would one of the derailleur ProConnect members confirm the width of the chain and the thickness of the Panasonic chainwheel teeth.

PS The Rohloff performs fine with 1/8" chain, and I have never experienced slippage with the 9T sprocket. My bike is not an "S".

 

[NRG]

3.22mm for 11T motor sprocket

2.2mm for 9T motor sprocket

2.2mm for 41T Chain wheel

with 3/32 chain...

 

[flecc]

That 11 tooth motor sprocket seems to be too wide for derailleur chains then NRG. The 3/32" of the chain roller widths is just over 2.38 mm, suiting the 2.2 mm items well.

 

[JamesC]

With further checking this morning, the 41T chainwheel is made in 2 widths - the original hub gear width that I use is 3.0 mm wide (for 1/8" chain), and the narrower width that NRG has measured at 2.2 mm wide (for 3/32" chain).

I don't have details about what widths have been made for 35T chainwheels or indeed about the motor sprockets.

James

 

[JamesC]

3.22mm for 11T motor sprocket

2.2mm for 9T motor sprocket

2.2mm for 41T Chain wheel

with 3/32 chain...

Thanks for the measurements NRG.

As Flecc points out, the roller length of 3/32" chain is 2.38mm which provides good clearance for 2.2 mm teeth.

However, I notice that at least one chain manufacturer, Wipperman, describes the 3/32" / 2.38mm chain as "8 speed" and describes 11/128" / 2.18mm as "9 speed".

Some of the ProConnect range use 9 speed derailleurs and I can imagine a sticky fit if 2.2mm chainwheel teeth are pushed into 2.18mm chain width. It would certainly need plenty of lubrication to perform.

Some care would be needed in selecting the best chain for the application.

James

 

[flecc]

With further checking this morning, the 41T chainwheel is made in 2 widths - the original hub gear width that I use is 3.0 mm wide (for 1/8" chain), and the narrower width that NRG has measured at 2.2 mm wide (for 3/32" chain).

I don't have details about what widths have been made for 35T chainwheels or indeed about the motor sprockets.

James

The 37 tooth chainwheels of the original motor unit came in two widths as well for hub or derailleur applications. I presume that was also true for their 14 tooth motor sprockets, but I was never able to check since that unit only appeared on Giant hub gear bikes in Britain.

It seems from NRG's width of the 11 tooth sprocket that it will have to specified for derailleurs where necessary. I believe all the "S" high speed versions use the 11 tooth motor sprocket and two of those use derailleurs, so the narrower version must be available.

 

[NRG]

My apologies chaps, the battery on my digital callipers was low when I took the measurements this morning. With fresh battery this afternoon the 11T and 12T are in fact 2mm wide.

As I had the chain cover off I decided to deep clean the chain and look at the idler wheel / motor sprocket alignment.

Careful observation and checking for 'rough' running I discovered on my bike the idler wheel was in correct alignment with the chain when using the 28T (2nd gear) rear cog.

Also, slackening off the retaining bolt for the idler to create some 'float' revealed a 2~3mm movement of the wheel from where it was when firmly held in place.

So I flexed by hand the metal cage where the idler wheel sits and aligned it correct with the chain when in 6th/7th gear...also I twisted the cage again be hand so that when the bolt was tightened up the idler wheel only moved very slightly if at all.

This has improved the feel of the chain when running in the top three gears but it has not eliminated it completely.

As the cage can be flexed by hand it would seem plausible that a small knock would shift the alignment and that maybe the owners complaining of this rough running and chain slipping in fact have a misaligned idler wheel...

 

[flecc]

Thanks for the correction NRG. Since all the newer unit motor sprockets I've seen have been flat, not stepped in thickness, and the mounting by a fixed circlip, I suspect that all motor sprockets are 2.2 mm, whether for derailleur or hub gear use.

 

[JamesC]

This thread is a little confusing as it covers two different issues. The first postings relate to transmission judder/noise on some hub gear bikes with rear wheel tension arrangements, and later posts relate to transmission judder/noise on some 9/10 speed derailleur geared bikes.

Like Tillson, I have followed this with interest because I have never experienced this sort of problem on any of the three hub geared Kalkhoffs (ProConnect, Tasman and Agattu) that I have ridden and worked on.

However, all 3 had the same, simple transmission system:
Wide 1/8" (3.2 mm) chain, anchored in place by wide teeth (3.0 mm) on the 41T Panasonic Chainwheel, and with plenty of slop within the chain for the remaining sprockets in the system to drop into place without needing extreme accuracy in their alignment.
9T motor sprocket 2.2 mm thick
11T Tension jockey wheel 2.1 mm thick
19T Nexus sprocket 2.3 mm thick

Using the "wide chain" strategy, the Panasonic drive unit can readily be matched up to a variety of hub gear units. Successful transmission is determined by chain length/tension.

Derailleur gears are a different kettle of fish because of the huge importance of matching the correct chain to the sprocket cluster. Much of the gearchange action is determnined by the chainlink profile on the outside of each chainlink, and the width of each chainlink is constrained by the fact that it must be able to sit between the sprockets in the cluster.

For Panasonic at the crank/pedal end of the chain, the wide 1/8" chain is no longer an option with derailleur. Two other chain widths have to be considered.

For 5/6/7/8 speed gear clusters, chain width is 3/32" (2.38 mm) - a very common size.
Typically the Panasonic equipment would need teeth of 2.2 mm or less.

For 9/10 speed gear clusters, chain width is 11/128" (2.18 mm).
Typically the Panasonic equipment would need teeth 2.0 mm or less for easy entry and exit into the chain.


I have some Panasonic parts from the early 1/8" chain/hub gear era and the latest 11/128" 9/10 speed era. (I am unsure as to whether there have been other sizes for 3/32" chain)

In particular, the latest 41T derailleur chainwheel is 2.0 mm and the 11T motor sprocket is 2.0 mm (compared with my 9T at 2.16mm).

NRG - I think that it is worth double checking your chainwheel if you are running 9/10 speed chain with a 2.2mm chainwheel. If it is 2.2mm, then it would be worth trying a 2.0mm chainwheel.

James

 

[NRG]

I've had another look at this in more detail again today as it was the earliest I could road test after my adjustment of the idler wheel and oiling of the chain.

It didn't take long to realise something was wrong, my PCS hasn't been suffering from the running symptoms mentioned in the previous posts but now it was...

Rough pedal feel under power, worse at low speed in a high gear and even more worse when using the high level of assist. The sound the chain was making was like a badly adjusted derailleur...

I took the chain cover off and took some photos, there was nothing obviously wrong other than the bracket of the idler wheel looked to be fouling the chain and the bracket itself was distorted as I'd probably overtightened the mounting bolt:

Correcting this made no improvement so I flipped over the motor drive sprocket on the drive shaft and tried again....it worked. Much smoother than before and no failing deraillieur sound.

I've taken a video of before and after to shown what is happening, they are just uploading at the moment so I'll edit or post new later.....

 

[NRG]

Finished sooner than I thought:

Watch the chain between the drive sprocket and the idler....it seems to get caught up under load, wrapping itself slightly too far around the sprocket....



[video]http://s94.photobucket.com/albums/l82/_NRG_/other/Bike/Kalkhoff/?action=view&current=SUNP0001.mp4[/video]

 

[flecc]

I take it that's the before NRG, and it would be typical of a trace of tooth hooking wanting to carry round the chain rather than let go. Your reversing of the sprocket will have presented clean teeth without any slight vestige of hooking. I noticed that Tim of 50cycles was very confident earlier when he specified changing the sprocket, probably from previous experience?

How many miles has that sprocket done NRG?

 

[NRG]

Yes, thats the before video, 9T sprocket has done about 500miles, so if it is hooking then these things wear quickly...thing is Flecc it was fine before I started playing with it so if it was wear then I would have though the hooking would have been evident before I took it apart....

 

[flecc]

At that mileage and on your evidence it seems hooking is very unlikely then. I've a feeling that because so few teeth are engaged on the 9 tooth standard sprocket, the teeth are made very deep as a resistance to slipping/jumping. The upper reach faces are almost vertical. Unfortunately, if all conditions are not exactly right, that will also tend to have reluctance to release the chain. Shimano's derailleur sprockets in contrast have the lowest profile in the business and the easy chain release that results gives them the fastest changing of any derailleur make.
.

 

[NRG]

That makes sense Flecc, I had trouble uploading the 'after' video but here it is, there is still some evidence of the chain not exiting the sprocket cleanly but its a lot better than previously...I also run the gears to the highest ratio in this vid and it seems OK...

[video]http://s94.photobucket.com/albums/l82/_NRG_/other/Bike/Kalkhoff/?action=view&current=SUNP0002.mp4[/video]

 

[tillson]

Thanks for posting the videos NRG, it makes it much easier to visualise the problem.

As you have already commented, it would appear that the chain is not releasing off the motor sprocket properly and is being carried beyond the point where it should release and pass smoothly onto the guide sprocket. The motor sprocket teeth appear to be, "picking / plucking" at the chain causing that awful rough noise and the chain vibration between the two sprockets. From what I have seen, this is not a chain slipping / jumping issue as originally thought.

What makes it even more strange is the fact that there seems to be very few issues with older units. My 2008 vintage is silky smooth. I hope that the fix is a simple one and that its not something fundamentally wrong with the geometry of the sprockets and their positioning relative to each other.

There are a few posts by different people reporting the same thing. Some with hub gears, some with derailleurs. Has anyone found / been given a long term satisfactory solution?

 

[mike killay]

Are the motor sprocket teeth too large?(ie the depth from point to valley)
Looking carefully at the video I got the impression that as the chain was leaving the sprocket, the driving face of the tooth was still in contact, but the rearward part of the tooth was in tight contact with the next roller. This meant that as the tooth angled away from its slot, its forward and rearward faces became jammed, thus pulling the chain beyond its normal release point.
If you have a spare motor sprocket, try running it a long the chain by hand to see if it does release cleanly