Derailleur as Chain Tensioner.

[Patrike]

If one is to use a rear derailleur for the slack chain when adjusting a bottom bracket (say Kyoto or DW), how much movement can one expect to get out of a BB before the chain is sagging again.

Thanks
Patrick

[AtomicZombie]

It depends on the length and spring tension of the rear deraillieur, but you should be able to get about 4-5 inches of adjustment before needing the link tool.

Brad

[Patrike]

It depends on the length and spring tension of the rear deraillieur, but you should be able to get about 4-5 inches of adjustment before needing the link tool.

Brad

Thanks Brad

Little shorter then I was hoping.

I am just thinking -- average people anywhere from 5.5 to 6.2. Wondering if I can come up with something that could gatherup around 8 or 10 inches. It is not required to carry the tension side so it can be of lite construction. I had built a tension side chain diverter thingy for my Tad that never worked out.

Will give it some more thought -- maybe combining somehow two derail's I can get more.

Later
Patrick

[AtomicZombie]

I hear what you are saying.

Of course, the difference in BB position for two people is not the same as the difference in their height. I am 5-8, my buddy Troy is 6-5. The difference in out BB position was only 4 inches.

Brad


Thanks Brad

Little shorter then I was hoping.

I am just thinking -- average people anywhere from 5.5 to 6.2. Wondering if I can come up with something that could gatherup around 8 or 10 inches. It is not required to carry the tension side so it can be of lite construction. I had built a tension side chain diverter thingy for my Tad that never worked out.

Will give it some more thought -- maybe combining somehow two derail's I can get more.

Later
Patrick

[Patrike]

I hear what you are saying.

Of course, the difference in BB position for two people is not the same as the difference in their height. I am 5-8, my buddy Troy is 6-5. The difference in out BB position was only 4 inches.

Brad

I was talking to John in Port Hope on Saturday(made my flanges and freewheel adapters) about this -- he pointed out the same thing. I guess it would be very rare to get a person it that height range that did not fall into that adjustment.

Given that difference you pointed out of approx 9" requiring only 4" ajustment in chain slack -- if you go for a range of people 5.0" (my wife) to any one else up to 6.5" -- an 8" slack adjuster should cover just about everyone -- this will be a little over kill - I will be taken to events like the trikefest in port hope and I want be be on the safe side. I think I have come up with a good ideal for a simple solution -- I will let everone know once I have tried it out.

Patrick

[savarin]

I was talking to John in Port Hope on Saturday(made my flanges and freewheel adapters) about this -- he pointed out the same thing. I guess it would be very rare to get a person it that height range that did not fall into that adjustment.

Given that difference you pointed out of approx 9" requiring only 4" ajustment in chain slack -- if you go for a range of people 5.0" (my wife) to any one else up to 6.5" -- an 8" slack adjuster should cover just about everyone -- this will be a little over kill - I will be taken to events like the trikefest in port hope and I want be be on the safe side. I think I have come up with a good ideal for a simple solution -- I will let everone know once I have tried it out.

Patrick

I have one on my machine you might like to look at.
http://www.members.iinet.net.au/~charlesmitchard/index.html
go to other projects, recumbent bicycle, there are a couple of shots that show how I fit it.
Yes, the front dérailleur is on the left hand side.