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Narrow q factor cranks Obree style

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speedy7777 View Drop Down
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    Posted: 08 April 2019 at 12:44am
I have been wondering if people here have made bikes with very narrow q factor cranks like Graham Obree had on his washing machine bike. Wouldnt it make a recumbent both more aero and also put the pedals in a more advantageous position for pedaling? if the flying scotsman film is true.
Just been  thinking about it while pedaling along and it feels like my legs would preffer to pedal closer together.
Could you suggest an easy way to modify a standard cranks (104bcd) / BB/ BB shell  to experiment with it without spending a heap of money on it? or what off the shelf parts would achieve it.
The narrowest bb for my cranks is about 108mm ( octalink dura ace) but i dont think thats narrow enough to make much difference. Current bb is 113mm.
Are any rear suspension recumbent frames (or even a round tube  boom only) made from new like that?

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JDub View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JDub Quote  Post ReplyReply Direct Link To This Post Posted: 08 April 2019 at 9:46am
Yes, narrow BB makes sense in every way. I made square taper axles from silver steel and used TA sealed bearings and cups. Quite a lot of work. This in Notso, which has a narrow steel shell. Most other solutions have less standard components. Kingcycle Beano for example I favour TA Cyclotourist cranks as they have a low Q. Not many available now. I have a plan to make steel tube cranks. Have faced the pedal thread area and cut back the shoulder on the pedals. Gained a few more mm.  
jdub... Got the T-shirt
http://s1127.photobucket.com/user/Protobikes/library
http://protobikes.org.uk/
https://www.flickr.com/photos/150386999@N02/

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JDub View Drop Down
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Joined: 01 November 2005
Location: Egham
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Points: 401
Post Options Post Options   Thanks (0) Thanks(0)   Quote JDub Quote  Post ReplyReply Direct Link To This Post Posted: 08 April 2019 at 9:49am
My axles are 81mm long. Royce will make them for you - at a price!

jdub... Got the T-shirt
http://s1127.photobucket.com/user/Protobikes/library
http://protobikes.org.uk/
https://www.flickr.com/photos/150386999@N02/

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