[python] Re: Geared Steering
- From: Logan Streondj <weyounet@xxxxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Tue, 28 May 2013 20:19:21 -0400
On Tue, May 28, 2013 at 2:28 PM, Kelvin Arthur <kelvin.arthur@xxxxxxxxx>wrote:
> Hi all
>
> The first version of my python I got up to 65km/h, it was pretty scary,
> but I flew past a road bike going down the same hill, and I ran out of
> gearing at 35km/h! I think experience will make the difference. Thinking
> back, if I had had handlebars, there's no way I would have been touching
> them, I was concentrating much too hard on what I was doing.
>
> I tried putting handlebars on it when I was first learning to ride, but
> quickly realised that they weren't actually helping me, so they came off
> and I pushed on.
>
> The idea may well have merit, but I think one of the posts had a good
> point, handlebars are naturally counter-intuitive on a python...
>
> My 5 cents worth...
>
> Thanks for your contribution,
that's what I thought, in terms that handlebars probably wouldn't be of
much help,
though again, it's hard to say since you didn't have them.
That's why I figured that the geared alternative can make going at high
speeds on the python a less scary proposition, since holding the levers
converts it from a wavy-boom to a rigid-boom, or at least rigid enough to
keep it straight with fine adjustments possible.
Currently none of the handle bars that have been implemented to my
knowledge worked with the pivot, I think in DF bike terms that would be
like having a handle on the front fender.
Also I'm not a "speed demon" I'm simply safety-conscious, and prefer to
have a safely controllable bike riding experience at all speeds, including
high ones that come with the terrain.
I live in Toronto near the Don Valley, and the speeds going through it mean
I usually achieve equal speed to the cars when going through, which is
around 50-60km.
It means if I was to use a python it would have to be safe at those speeds
to do it regularly, and loaded with heavy cargo like groceries.
> Sent from my iPad
>
> On 29/05/2013, at 5:25, Patrick van Gompel <patrick_van_gompel@xxxxxxxxxxx>
> wrote:
>
> Ah ok. Well sorry, I have no experience with driving 66+km/h on a Python.
> Even on a recumbent (Condor) I get a little scary when driving 70km/h and
> whould never take my Python that far.
> So I am sorry I can't help you much with those speeds and I can't tell
> what the effect of a normal handle bar would be.
> You were talking about a 'low-walker', so that confused me, because I
> don't think that a Python is slow. I have never been able to pedal my
> Python faster than I could handle, but hey, I am no speed machine ;-) And
> there aren't hills around here to get 66+km/h speeds.
> Patrick
>
> ------------------------------
> Date: Tue, 28 May 2013 12:17:57 -0400
> Subject: [python] Re: Geared Steering
> From: weyounet@xxxxxxxxx
> To: python@xxxxxxxxxxxxx
>
> well I was thinking mostly to stabilize things like going downhill very
> fast,
> I read a review online that said it was "puckerish" and he could only
> achieve a speed of 66kph vs 90+kph with rigid boom, had to engage the break
> and even then it wasn't pleasant.
> http://www.recumbents.com/forums/topic.asp?TOPIC_ID=4226
>
> I like the python center-steering, but I'd also like to be able to go fast
> downhill without having to do too much work getting it to go straight.
> There are a bunch of hills in my area with relatively high speed traffic,
> so it's important that can maintain control.
>
> If ordinary handlebars are enough to make it easy to go downhill at high
> speed, then I guess that'll be enough,
> it was just my understanding from that post that it wasn't, though perhaps
> they weren't using handlebars for that downhill testing.
>
>
> On Tue, May 28, 2013 at 11:13 AM, Patrick van Gompel <
> patrick_van_gompel@xxxxxxxxxxx> wrote:
>
> My thoughts:
> A Python is a leg/hip steered bike. You can have handle bars anyway you
> like, but for a newcomer it might be even more confusing. You really need
> to learn to steer in a different way and forget about steering with your
> hands.
> I did have and still have a handle bar on my Python(trike). When I learnt
> to cycle I always got rather tired arms, because my legs would go one way
> and my arms tried to correct that (which was bad). Now I use the handle
> bars for extra stability and sharp cornering.
> Looking at your drawing:
> Unless you succeed in making this a durable construction I doubt it will
> survive the big forces for much time.
> I am not saying you should't try it, but why do you prefer this
> construction above a simple handle bar?
> Why are you worried for the forces at high speeds? I am more worried for
> slow speeds and when you legs go one way and your arms try to go the other
> way. At high speeds you don't need much force to steer imo.
> I am not entirely sure, but if you have a 1:1 ratio I think you will have
> a hard time steering your bike with your arms only. Though, it also depends
> on the lenght of your levers.
>
> Patrick
>
> ------------------------------
> Date: Tue, 28 May 2013 10:44:57 -0400
> Subject: [python] Re: Geared Steering
> From: weyounet@xxxxxxxxx
> To: python@xxxxxxxxxxxxx
>
>
> hmm, well the ones I linked to are 3:1 and I think it's already too much,
> I think 1:1 is okay considering have levers at both arms, and it also would
> make it the same refinement of motion as on a normal bike.
>
> Based on your recommendation, you might have a different Idea than I about
> how the gears are to be implemented, so I've drawn a crude crayon diagram
> to hopefully get us ":on the same page" [image: Inline image 1]
>
> I made it based on the picture of the pivot at
> http://www.python-lowracer.de/pics/kick_stand_with_steering_stop.jpg the
> gear would go approximately where the bell is now.
>
> Also I realize having the diagonal levers may make it too close to the
> seat, so could probaly make them kinda like L's so they give enough
> clearance.
>
>
> On Tue, May 28, 2013 at 9:34 AM, Peter Švančárek <peter.svancarek@xxxxxxxx
> > wrote:
>
> to low gearing ratio probably... long lever would be better.
> Maybe planetary gear would be better? with ratio at least 1:10-20
>
> Dňa 28. 5. 2013 15:15 Logan Streondj wrote / napísal(a):
>
> Hey,
> I was wondering if can improve the steering at high speeds,
> perhaps by having some kind of gearing mechanism on the pivot,
> that would for instance move levers on either side,
> the levers could be used to hold the pivot at a certain angle, or change
> it to an appropriate one.
>
> perhaps bevel gears could be used.
> If for instance the lever gears are mounted on the back boom,
> and the pivot gear controls the front boom,
> then could have very precise control of the front-back boom angle.
> main issue I guess would be finding good mounting options,
> and making sure it has enough strength to withstand the forces at high
> speeds.
>
>
> That way can finally achieve the inital goal of using it as a low-racer,
> rather than a low-walker as it kinda is now.
> who knows, might even win at some recumbent bicycle races.
>
> It may also make it easier to learn for newcomers, since there would be
> some kind of steering available.
>
> Perhaps something like the larger of these gears could be used
> http://www.ebay.ca/itm/5-9mm-Pinion-Shaft-Dia-Straight-Bevel-Gear-Spare-Parts-/390574215222?pt=LH_DefaultDomain_0&hash=item5af0099036they
> are $10 on ebay and I saw some for 6 not too long ago, would need
> three, one for the pivot, and two for the levers on either side.
>
>
>
>
>
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