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Wednesday, April 01, 2009

BICYCLE FRAME EXTENSION PART 2 CHAIN MANAGEMENT

It's not a little thing like a coronary that's going to keep me back from some R&D on my latest Sport Utility Bike project...all right it does make me go a bit slower I'll admit.

So once the frame extension is in place, I had to install the rear derailleur and chain. In this case about two chains and a half compared to a regular bike. All that chain and the places where it is supposed to run is an invitation to slapping around and grinding some frame paint! This is where chain management comes into play.

This is one of the first things you learn, by force of necessity, when building homebuilt recumbents. The chain is a lot longer and runs through a whole bunch of funky places, it needs to be guided along. In our case, it's a pretty simple case of slightly guiding the chain and giving it some extra tension. For that purpose I use hard plastic hose made for underground lawn sprinklers. It can be found at the local hardware super store and I bought mine at $10 a few years ago for a roll of 100 feet.


The hose will eventually need to be replaced after a few thousands miles. Despite the looks, this set up is surprisingly quiet. You can use something a bit better looking than black tape to keep the hose in place, but it does the job quite well.

Next step will be to put together the big rack. I have some steel for the framing and I'm thinking about using some left over flooring wood for the main top body.


Until next time, ride safe and Godspeed.

Gerry :)

2 comments:

The Frugal Scotsman said...

Gerry,

I've been reading your blog for about a year now. Your hard work and excellent information has gotten me out of many a tight spot. Many thanks for sharing your experience on your blog.

My sympathies on your unpleasant experience experience, but I'm glad that you are on the mend!

Here's to a fast recovery and many more recumbents!

Ken Davidson said...

Hi Gerry, I echo Frugal Scotsman's words (I'm another frugal Scot!) - my neighbour had a large heart attack a few months back, and currently has two stents in place. He's recovered well, and never really stopped tinkering with his classic cars and bikes = good therapy ;)

Recumbent chains: I'm not criticising your plastic tubes guides, as I recognise your no-nonsense low-cost approach. Clearly in an ideal world the chain would follow the straightest path possible, with minimum contact - perhaps only using secondary cogs to guide the path. I was amazed recently to see an 8 Freight cargo bike where the chain actually 'touched itself' at a crossover point under the chassis - I'd've thought this was mind-boggingly bad engineering for what is hailed by some as a 'quality bike'. It's just a glancing touch, so no grinding going on but...

Is this common practice? Labelled pic here http://tinyurl.com/cmq4yw