[python] Re: Whoops, when did I start thinking 5 cm was only 5 mm?

Hi Michael!

I've made a Python to a guy which has 1.69 m and has a inseam of 79 cm. We use 
26" x 1" tyres (real 24" diameter). You may see the pictures at Jürgen's page 
in the "Modifications" link.

[]'s Eduardo

Ypê Bike: http://www.ypebike.cjb.net/
Ypê Mono: http://www.ype.unicyclist.com/
  ----- Original Message ----- 
  From: Michael Rienstra 
  To: python@xxxxxxxxxxxxx 
  Sent: Saturday, May 08, 2004 5:28 PM
  Subject: [python] Whoops, when did I start thinking 5 cm was only 5 mm?


  Hello all,

  Reading Bjørn & Jürgen's discussion of inseams, I realized that I forgot that 
my inseam is 5 cm too short and started thinking that it was only 5 mm too 
short!

  So forget my amazing plan. The absolute maximum I could shorten the distance 
between the steering BB and the FWaP is 2 cm. As per "The absolute minimum 
distance [between BB and FWaP], I would recommend is 40 cm (84 cm inseam)." 
(from http://www.python.tieflieger.net/construction.html ), I could shorter the 
front 2 cm as well, although using the absolute minimum seems like a bad idea.

  So let's assume I shorten the distance between the steering BB and the FWaP 
by 1 cm, and I also shorten the distance between BB and FWaP by 1 cm. Then my 
81 cm inseam 'becomes' an 83 cm inseam. I can't reduce the BB<-->FWaP anymore 
without causing problems, so I need to reduce the SBB<-->FWaP by 3 cm (in 
addition to the 1 cm reduction), which means reducing the outer diameter of the 
tires by 6 cm. Hmm, although reducing the tire diameter will also reduce it's 
width, reducing interference between the sides of the tires and the 40x10 
tubes, so it should be possible to reduce the SBB<-->FWaP by 3 cm (in addition 
to the 1 cm reduction) without having to reduce the tire diameter by a full 6 
cm.

  Another option is to redesign the SBB<-->FWaP connection to something more 
like the letter "U" (bottom of the "U" is the SBB, sides are the 40x10 tubes) 
then the letter "A" (top of the "A" is the SBB, "A" cross bar is the cross 
member, sides are the 40x10 tubes), so that the tire could sit much closer to 
the SBB axis. It looks like it could be reduced by a good 4 cm or so (total), 
so if I reduce the SBB<-->FWaP by 4 cm total (from 38 cm to 34 cm) and I reduce 
the BB<-->FWaP by 1 cm (from 42 cm to 41 cm), then my 81 cm inseam should be a 
perfect fit with everything else standard (44-559 tires, etc).

  Michael

  PS: I found an oxygen tank to complete my oxy-acetylene setup! I'm getting 
closer and closer! Plus, the face shield and the gloves are more like optional 
accessories than essentials, right? (Just kidding!)


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