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Subject: 
Re: building a bicycle -- can it be done?
Newsgroups: 
lugnet.technic
Date: 
Sat, 2 Sep 2000 03:54:08 GMT
Viewed: 
815 times
  
In lugnet.technic, Geoffrey Hyde writes:
Very nice solution.  But we're building a bicycle, not a car!!
Differentials are ungodly bulky things, but for technical accuracy, they
might do the trick!!  Have to upgrade the elephant cyclist to a hippo or
whale now!  ;-)

Well, I have to agree-- the differential is an elegant solution, but a little
more complex than necessary... a single ratchet does the trick by itself
without really needing the differential. I'd say that there's also the size
issue too, but after playing around with my own solution a bit, I think a
self-made wheel would have to be the way to go for any sort of semblance of
reality.

While playing around with my own solution, the smallest width I could get for
the rear wheel gears was 7.5 max. From outside in, 1 stud for the outer
support, two gears for the chain (24 cog then 40 cog), 1 stud for a housing for
the rachet (I just couldn't manage fitting a ratchet onto the 40 cog gear that
would really lock any smaller size gear), 1 stud for the ratcheted gear, 1 stud
for the wheel (largest I have-- as seen in Mindstorms kit), .5 stud for
clearing the outside of the wheel (wheel is 1 stud wide, outer tire is 2 studs
thick), and one final stud for the support on the opposite side.

Anyway, while I'm quite pleased with the ratchet mechanism itself (it works
exactly like a real bike) but the size just makes it poor for proportions. I
think the best way to do it would probably be to make your own wheel-- using
various slopes, etc. Although I have no idea how sturdy that would be...
probably not very, assuming that you made it with an attempt at spokes, etc :(

DaveE



Message is in Reply To:
  Re: building a bicycle -- can it be done?
 
Very nice solution. But we're building a bicycle, not a car!! Differentials are ungodly bulky things, but for technical accuracy, they might do the trick!! Have to upgrade the elephant cyclist to a hippo or whale now! ;-) Cheers ... Geoffrey Hyde (...) (24 years ago, 2-Sep-00, to lugnet.technic)

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