I'm a little nervous about the belt drive for winter, because I'm afraid that snow and ice would pack into the cog and either snap the belt or cause it to slip. I've found cases of it happening with shaft drive motorcycles.

Dynamic shaft drive bicycle
 

Thanks tjspiel. Sorry about the long paragraph. That's what happens when I drink wine and write. I had to get on the Forum this morning just to be sure I hadn't written something I shouldn't have.

meanwhile;

Interesting looking dual suspension bike. As no visible belt tensioner the rear suspension pivot must be concentric with the bottom bracket. That is something which has rarely been done on FS bike designs.

I think the drive belt technology looks promising. It offers everything that a conventional chain does. And it could be adapted to existing bikes.

With current materials technology it is wide enough so not going to see it on a derailleur bike. To adapt to current bikes would require a joint in the belt for installation and removal which would almost certainly be the weakest point, risking failure.

It looks like these bikes have the same kind of rear drop-outs as track bikes have, with the slot facing backwards. One of the road "fixies" that some companies are now selling might be suitable for conversion.

As tatfiend alluded to, the problem with belts and standard bike frames is how to get the belts on and off. With a chain you use a chain breaker or master link. There's no such animal with a belt so the frame has to be specifically designed to allow belt installation and removal.

Tatfiend is correct that it cannot yet be used with a standard frame and with derailleurs. The late Sheldon Brown maintained the greatest drawback of a belt drive system is that it cannot be customized. Until both problems are solved, its potential application is going to be limited. As I said, its promising but nothing more than that right now.

Dynamic Chainless bicycle
 

Hello All,

This is in response to the long post by "sookieplume" regarding Dynamic Chainless bicycles. I bought a Dynamic bicycle over a year ago. I use it for my daily commute (10km round trip along a flat gravel path). Even though I live far away from the Dynamic folks, they have been very helpful on the phone and the initial shipment here to Switzerland was very fast.

I think I'm the only person in Switzerland with such a bike. I love the fact that it doesn't have a chain. The wheels, brakes & frame are great. I had a problem earlier this year with the shaft though. The nice folks at Dynamic spent hours with me on the phone patiently explaining things I could try out. They then sent me a new shaft free of charge. I think that's great customer service.

The probelm I had from the beginning was with too much torque, the shaft started crunching. As I live in Switzerland, we do have a few hills. I took the shaft apart and expected to see broken teeth. The teeth were all fine but I could not use the bike up hill nor could a go faster than a very leisurely pace without this terrible crunching. Over time it got worse so that the bike could not be used at all.

I've now installed a new shaft and have ridden back and forth to work 10 times. The first few days were great. I thought my problems were over. After day 4 or 5, strange noises have again started to come from the shaft. Last week I took my old beach cruiser (with a chain) to work instead as I didn't like the creaking noise coming from the shaft.

I have several theories what is going wrong:

1. The shaft is not fully sealed, dirt can get in through the back. Perhaps dirt, pebbles, etc. comes in through the back. I do ride along a gravel path.

2. I weigh 220 lbs. Perhaps this shaft just can't take the torque. Perhaps shaft driven bicycles just can't handle folks that weigh that much.

3. Perhaps I'm really unlucky and have a lemon (inspite of the second shaft)

4. Perhaps these problems occur with all these bikes and chains are a superior technology.

5. Perhaps my local Swiss bike shop screwed something up when they installed an automatic dynamo light system (I can't figure out how this would have anything to do with the shaft).

6. Perhaps I have to add grease. Should I really have to add grease after only 50 km??

Any ideas anyone?

Karl from Switzerland

You might want to check out this article: http://www.treehugger.com/files/2008...elt-drives.php

The drive system was developed by Gates who also makes belt drives for snowmobiles. Apparently "mud ports" were designed into the system so that snow, mud, and other crud would be shed.

ksteinke;

I have seen enough reports similar to yours regarding Dynamic shaft drive problems so that I suspect some design or manufacturing problems. IIRC another BF member reported problems using one in San Francisco. Again a heavy rider who reported riding out of the saddle at high power on hills. Do a search for Dynamic bikes here on BF and you will pick up multiple threads.

Try regreasing as it should not hurt but I suspect possible end play or other adjustment problems with the shaft may have developed.

As you are in Switzerland you might have done a German Ebay search for a Fendt Cardano bike. These were a German shaft drive that was supposed to be quite reliable I believe.

add grease- to Ksteinke
 

Yes, add grease. Whenever the drivetrain makes noise, add grease. Then add some more. I have more than 3000 miles, and I have filled the gearbox up with grease - no noise in hundreds of miles.
Grease is the weak spot of the dynamic bike drive. At purchase, the buyer should fill the gearbox up with grease. This will save trouble later.
MRiley