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 Fwd with no idlers?
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DeanV
Starting Member

New Zealand
24 Posts

Posted - 01/29/2012 :  12:58:53  Show Profile  Reply with Quote
I am thinking of doing a fwd with the bottom bracket fixed to the frame (i.e not moving with the steering) and immediately in front of the steering head. The drive would then be straight down to the wheel with no idlers as you would normally have with the bb further forward. I was going to use 650c wheels front and back.
Are there any problems with this configuration? I can see that the front wheel will not have that much weight on it but I would think traction should be sufficient for reasonably flat roads with a good surface.

tom porter
recumbent enthusiast

157 Posts

Posted - 01/29/2012 :  13:49:38  Show Profile  Reply with Quote
The only difficulty will be designing the distance from the BB to axle, this should be about 17" which is the ordinary distance on a DF. This is necessary for chain wrap. It's been done before but I haven't seen one in years.

O---o
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Jeff Wills
human power supergeek

USA
1204 Posts

Posted - 01/29/2012 :  15:20:01  Show Profile  Visit Jeff Wills's Homepage  Reply with Quote
I think the Rotator "Big Gun" streamliner had a drivetrain like that:




FYI, Warren: my pictures from that year have moved to http://www.ohpv.org/events/albums/bm2002/hpsc2002.html

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Jeff Wills
All my bikes:
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alevand
human power supergeek

USA
1890 Posts

Posted - 01/29/2012 :  15:39:38  Show Profile  Visit alevand's Homepage  Reply with Quote
http://www.youtube.com/watch?v=1syBw8j8-sI

C:
Tony Levand
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Speedy
recumbent guru

USA
751 Posts

Posted - 01/29/2012 :  17:43:46  Show Profile  Reply with Quote
Big Gun needed a mid-drive to multiply the ratio so no that's not the one
this is :

https://picasaweb.google.com/111289919904122427931/LaborsOfSteveDelaire?authkey=Gv1sRgCN3E8MCI9KnVpwE#5636077097679182034

or the picture right after
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sean costin
human power supergeek

Lesotho
1976 Posts

Posted - 01/29/2012 :  18:14:52  Show Profile  Reply with Quote
My bike "Little eddy" was like that. Very efficient, but low traction on the front wheel.
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PUGZCAT
recumbent enthusiast

Canada
277 Posts

Posted - 01/29/2012 :  19:09:27  Show Profile  Reply with Quote
http://tricolour.net/photos/2008/11/22/11-47-08i1.html

My no idler twist chain drive, dual wheel steering, everything adjustable thing.
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DeanV
Starting Member

New Zealand
24 Posts

Posted - 01/29/2012 :  22:08:13  Show Profile  Reply with Quote
quote:
Originally posted by Speedy

Big Gun needed a mid-drive to multiply the ratio so no that's not the one
this is :

https://picasaweb.google.com/111289919904122427931/LaborsOfSteveDelaire?authkey=Gv1sRgCN3E8MCI9KnVpwE#5636077097679182034

or the picture right after


That is what I was thinking of.
Any idea on how this would perform in a TT compared to a Nocom lowracer?
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ballo
Starting Member

Australia
2 Posts

Posted - 01/30/2012 :  00:12:40  Show Profile  Reply with Quote
I can't offer a proper speed comparison, but I thought I'd share that a few local bulders in Melbourne have built very rideable machines with the same drivetrain. Both of these bikes have been used regularly in some configuration for a few years now - both for recreation and commuting.


This is the newest iteration of this particular bike, but Steve has older pics on his personal site http://modularbikes.com.au/bigatthefront.html

Cheers
Eric
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Speedy
recumbent guru

USA
751 Posts

Posted - 01/30/2012 :  06:40:16  Show Profile  Reply with Quote
my gut thinks it would do well
the facts ... I have not had a Nocom to do a coastdown against
although
it was quite a bit faster against the other lowracers tested on the same course
the ti / carbon version breaks apart to fit in the back seat of a small compact car
the only race event I used it in was at the Encino velodrome where I averaged 26 with a very low heart rate ... taking it easy to get a feel of the new bike



quote:
Originally posted by DeanV

quote:
Originally posted by Speedy

Big Gun needed a mid-drive to multiply the ratio so no that's not the one
this is :

https://picasaweb.google.com/111289919904122427931/LaborsOfSteveDelaire?authkey=Gv1sRgCN3E8MCI9KnVpwE#5636077097679182034

or the picture right after


That is what I was thinking of.
Any idea on how this would perform in a TT compared to a Nocom lowracer?

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E.B. Erickson
Starting Member

49 Posts

Posted - 01/31/2012 :  04:08:22  Show Profile  Reply with Quote
The German Bevo Bike has a similar setup to those already shown, but the top of the fork is offset to allow the chainline to be aligned along the center of the headtube. It looks like this approach would minimize any steering effects induced by the chain.

--ElJay
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rzon
Starting Member

USA
7 Posts

Posted - 04/22/2012 :  07:41:49  Show Profile  Reply with Quote
http://i1049.photobucket.com/albums/s384/rzonrzon/http.jpg
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rzon
Starting Member

USA
7 Posts

Posted - 04/23/2012 :  04:34:57  Show Profile  Reply with Quote
This is a traveling bike. Swing arm folds and the bike fits in a 4ft hockey bag.
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Blue Ridge Biker
Starting Member

USA
15 Posts

Posted - 04/23/2012 :  06:29:11  Show Profile  Reply with Quote
quote:
Originally posted by rzon

This is a traveling bike. Swing arm folds and the bike fits in a 4ft hockey bag.

What X-seam is that set up for? How many teeth on the chainrings?
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rzon
Starting Member

USA
7 Posts

Posted - 04/24/2012 :  05:59:17  Show Profile  Reply with Quote
The x-seam is 42" and the chainrings are 72 tooth rzon and 60 tooth Vuelta. The design of this bike would work better with a lighter rider.(fork issues)
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