[trikes] steering design question

[John Turvey]

On Thursday, October 28, 2010, at 07:21 PM, Alex Richards wrote:

> My wife was recently told she should use a wheelchair due to her ME. 
> As keen cyclists we'd like to continue, and so I've been looking at 
> designing an attachment for her chair which would convey it to 
> something like a Vietnamese cyclo rickshaw
>
> http://www.rfleming.net/diarypics/Huecyclo2.jpg
>
> Only thing I'm not certain about is the location of the steering 
> pivot; should it be between the wheels like a kids soapbox kart, or 
> behind the wheels like another conversion I've seen?
>
> Any advice would be gratefully received.
>
> Alex
>
>
There are several commercial machines available which are similar to 
this, where the wheelchair front and the 'cycle' rear can be split so 
the wheelchair can be used separately (in cafes etc) - however, the 
wheelchair part is much sturdier than a wheelchair, as it has to 
withstand the higher speeds of cycling - from my recollection of these 
sorts of machines, the steering pivot is slightly in front of the front 
wheel centres - to provide some trail and (presumably) damping to the 
steering.

Have you looked for this sort of machine on the web - a good starting 
point is the Velovision Special Needs Cycling Guide at

http://www.velovision.com/cgi-bin/show_comments.pl?storynum=559