[python] Re: wheel flop vs pedaling induced steering
- From: Ronald Hongsermeier <rwhongser@xxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Thu, 29 Nov 2007 01:08:54 +0100
Comments below:
> -----Ursprüngliche Nachricht-----
> Von: python@xxxxxxxxxxxxx
> Gesendet: 28.11.07 13:52:50
> An: python@xxxxxxxxxxxxx
> Betreff: [python] Re: wheel flop vs pedaling induced steering
>
> George is right. PSI = Pedalling-Steering Interference. Some call it PIS
> (pedal induced steering). Someone with english mother tongue might tell
> us which one sound more correct ...
>
PSI is an old notation from science: pounds-sq.in. for reporting pressures.
Pedal Induced Steering sounds more elegant when you say the whole word. For our
welsh friend, PIS is only 3/4 (or less) of urination, etc. and according to my
graduate level prof in TESL would be pronounced like "peace", if somone should
try to do so, since a syllable with a single asperant after a vowel makes the
vowel long since the syllable is not heavy...
If everyone but me wants to go with the former, please put a "/" in-- as in
Pedalling/Steering Interference or P/SI, then I won't be confused thinking
someone's gassing off-thread. ;-)
I'll be going for my first welding lesson tomorrow if things go well :-]
ron
> Wheel flop (WF) should carefully be separated from PSI because it is a
> different thing.
>
> WF is caused by the angle of the steering pivot being too small, or the
> weight of the front part being too heavy, or the CoG of the front part
> being too high.
>
> The PSI is dependant of the position of the steering pivot relatively to
> the riders hip joints (at least in my theory). If the steering axis goes
> right through the center between the riders hips then PSI is minimized.
> You will find this at all center-steered bikes. See pictures on my
> modifications page.
>
> That is why TT-clones like Cruzbikes have noticeable PSI and need
> additional arm force to compensate it. However TT-clones with very low
> BBs and followers of the a<b rule like Laurent's Speculoos and Jürgen
> Maier's bike also can minimize the PSI.
>
> Unfortunately no scientific essay or proof exists for these assumptions.
> It is just empiric observation from the practice. Looking forward to
> someone who is expert in technical mechanics ...
>
> Cheers,
> Jürgen.
>
>
>
>
> On 28.11.2007 07:42, Dirk Steuwer wrote:
> > Hi Listies,
> >
> > The other Dirk has added a page about the pivot angle and his influence to
> > the
> > wiki:
> >
> > http://en.python.data.he-hosting.de/Pivot_Angle
> >
> > What should follow this is a closer definition of wheel flop and pedaling
> > induced steering. They do have in common that the front part start to
> > wobble.
> > Buzt what sets them apart? Isn't wheel flop also related to the wheight of
> > the front? Does the a<b distance matter as well, besides the pivot angle?
> >
> > See this image http://python-lowracer.de/pics/TT%20Juergen%20Maier.jpg
> >>from Jürgens Modification page: http://python-lowracer.de/modifications.html
> >
> > i was going to dig through old posts and prepare an additional graphic for
> > illustration.
> >
> > Should we handle the two in one wiki page?
> >
> > Why do we call it PSI, when we talk about pedal induced steering? Or do i
> > mix
> > up things here?
>
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