[python] Re: python Digest V9 #118
- From: Vi Vuong <vi_vuong@xxxxxxxxx>
- To: "python@xxxxxxxxxxxxx" <python@xxxxxxxxxxxxx>
- Date: Thu, 4 Aug 2011 23:22:50 -0700 (PDT)
Hi Howard,
Yes our trikes have pivot angle ranging from 65 to 30 deg and similar PSI
trend. High speed stability seems to be a problem with lower angle, hence
damper on the Hippiron. At 30 deg, sprinting is great ~no PSI but wheel flop
is really bad. I have a bike pivot at 70 deg, and steering is very demanding,
but good for learning finer control or abdominal workout. Overall, I would say
that pivot angle is such a luxury / finner parameter on a trike. While on a
bike, it's a critical (go or no-go) parameter for a new rider...
Regarding leaning, I find my upper body twisting and leaning a little at higher
turning angles, even on bikes. Contour seat helps. I played safe with trike
tracks as wide as the donor frame / tubing allows (30"-50") but find that
leaning still helps for smooth transition out of fast corners, same as driving
I think. Your track seems to be about ~25", so definitely lean. It's also
good for abs... :)
Vi
>________________________________
>From: Howard Stevens <hstevens94@xxxxxxxxx>
>To: python@xxxxxxxxxxxxx
>Sent: Tuesday, August 2, 2011 5:22 AM
>Subject: [python] Re: python Digest V9 #118
>
>
>Hullo Python trikologists,
>I have been following your discussion with interest but as yet have not had
>the opportunity to test my trike out much, only doing a few rides around the
>district.
>There are a couple of points I would like to make however, and wonder if
>others are finding the same results.
># My python trike definitely has a "sweet spot" around the 52degree of pivot
>angle. I had a lot of PSI problems at 62 degrees, but reducing the angle now
>gives me comfortable, direct steering with minimal PSI. The Hippiron trike
>also had a similar angle. Are others finding that trikes are different to
>bikes in this regard?
># I wouldn't bother with rear brakes and find that the single front disc brake
>is excellent, and pulls me up with quite a jolt.
># I find turning is a bit uncomfortable at speed and requires some leaning,
>but then I am a sedate grey nomad, in no particular rush!
>All the best Howard Stevens
>
>
>On Tue, Aug 2, 2011 at 3:07 PM, FreeLists Mailing List Manager
><ecartis@xxxxxxxxxxxxx> wrote:
>
>python Digest Mon, 01 Aug 2011 Volume: 09 Issue: 118
>>
>>In This Issue:
>> [python] Re: AW: Re: Questions about Python-Trike geometry (
>> [python] Re: AW: Re: Questions about Python-Trike geometry (
>> [python] Re: AW: Re: Questions about Python-Trike geometry (
>> [python] Re: AW: Re: Questions about Python-Trike geometry (
>>
>>----------------------------------------------------------------------
>>
>>From: Patrick van Gompel <patrick_van_gompel@xxxxxxxxxxx>
>>Subject: [python] Re: AW: Re: Questions about Python-Trike geometry (project
>>si
>>Date: Mon, 1 Aug 2011 15:12:34 +0200
>>
>>Ah, thanks for your explanation! Yes, having just rear brakes on a trike is
>>not a good idea. A front brake will make all the difference.
>>
>>I can't help you with the geometries, as I haven't tried (many) different
>>setups.
>>My 'magic moment' was there when I temporarily attached two wheelchair wheels
>>on my Python. Although the construction was weak and the track was too small,
>>it did give me a sudden insight of how the Python was steered. On this trike
>>the cycling was very easy. It appeared to me that steering wasn't the actual
>>problem, but keeping balance was. That might sound like an open door, but
>>when you steer on a Python your centre of gravity is actually shifted to the
>>outside of the corner. That means that you have to lean more than on a
>>conventional bike. I still have problems with that when I make sudden sharp
>>corners.
>>
>>Thanks,
>>Patrick
>>
>>
>>> Date: Sun, 31 Jul 2011 21:34:39 +0100
>>> To: python@xxxxxxxxxxxxx
>>> From: Rhisiart@xxxxxxxxxxxxxx
>>> Subject: [python] Re: AW: Re: Questions about Python-Trike geometry
>>> (project similar to Howard Stevens foldable Python trike)
>>>
>>> Hi Patrick,
>>>
>>> Well since I wrote, I've put the trike back-end back on my Python,
>>> just to have another think about it.
>>>
>>> It rides really well, and I have literally instant control; had it
>>> from the very first try out in fact, and went out on the road in
>>> traffic that first day.
>>>
>>> So what I'm doing now is putting a brake on the front wheel (I hadn't
>>> done that before) and I'm fixing a method to pull on both back brakes
>>> by a single hand lever. I may also try two brakes on the front wheel,
>>> operated by both hands, if the back brakes are just hopeless. I'll
>>> report results.
>>>
>>> I must say too that being able to bank all of the trike, except the
>>> rear-wheels frame, into bends, just like on the bike, is a real plus.
>>> (Erik Wannee's training back-end photo shows you exactly the design
>>> principle) It feels just like riding the bike, except that you have
>>> those brawny handle-bars, fixed to the back end, to push down/pull up
>>> on. I find that I do both at once when I feel myself going over. Just
>>> like pushing frantically against the ground with your stretched
>>> fingertips, but so powerful by comparison that you can stop all
>>> fall-overs dead before they get going.
>>>
>>> And I've already noticed, even on my fairly short total time on the
>>> banking trike that there is indeed a training effect for staying
>>> balanced, so that you begin to be able to lift your hands slightly
>>> off the bars for a few metres at a time. I suspect that with plenty
>>> of use of the trike I should be able to ride the bike with
>>> confidence, before long. You can see from the videos that there's a
>>> knack; that first-time riders suddenly get it. That's the magic
>>> moment that I'm shooting for!
>>>
>>> It does occur to me, though, that since we've all made our Pythons
>>> ourselves, to no standard design, might it be that subtle, quite
>>> small variations in bike geometry make all the difference between an
>>> easy, sweet-riding bike where you get the knack easily and within
>>> minutes, and a really tough dog? I seem to have made a tough dog.
>>> Anyone got any ideas about that, based on experience with several
>>> slightly differing geometries?
>>>
>>> Hwyl, Rh
>>>
>>> >Are you saying that you abandoned a beautifull trike design because
>>> >of rear wheel skiding when braking? I want to build a python trike
>>> >myself, so I wonder why you would worry about it. I mean, if just
>>> >the front wheel is enough for braking, then why bother about the
>>> >rear? My two wheel Python doesn't even have a rear brake. Or is it a
>>> >safety concern? Though, you could always fit multiple brakes on just
>>> >the front.
>>> >Please let me know you thoughts,
>>> >Patrick
>>> >
>>> ============================================================
>>>
>>> This is the Python Mailinglist
>>>
>>> //www.freelists.org/list/python
>>>
>>> Listmaster: Jürgen Mages jmages@xxxxxx
>>>
>>> To unsubscribe send an empty mail to
>>> python-request@xxxxxxxxxxxxx
>>> with 'unsubscribe' in the subject field.
>>>
>>> ============================================================
>>>
>>
>>
>>------------------------------
>>
>>Date: Mon, 1 Aug 2011 07:16:28 -0700 (PDT)
>>From: Vi Vuong <vi_vuong@xxxxxxxxx>
>>Subject: [python] Re: AW: Re: Questions about Python-Trike geometry (project
>>si
>>
>>Hi Rhisiart,
>>Since our bike/trike experiments are quite similar, I would to suggest the
>>following:
>>
>>1. If pivot angle is higher than 60, find smaller wheels to try lower angles
>>since you now have front brake. In my case, I went up from 48 deg... If
>>there is a quick way to raise your seat, bring it as high as you can. Use
>>sticks if you can't reach the ground.
>>
>>2. Take off with fingers / sticks lightly resting on the ground (no leaning),
>>and with as much pedaling force as you can without inducing steer (same trick
>>to start with hands in the air). While training new riders, I obverse that
>>they don't pedal hard enough and instead focus more on balancing and end up
>>getting out of balance (I did the same but just couldn't see it). If you can
>>"consciously" get some momentum going, your body/brain will amazingly take
>>care of the rest... See my shaky
>>and hesitant takeoff http://www.youtube.com/watch?v=6yBjSGL_pd8#start=0:00;end=0:07;autoreplay=true;showoptions=true
>>
>>3. Once you learn to take off, you can take all the time you want with other
>>riding aspects, and different configurations (levels of difficulty).
>>Switching configurations / bikes can take a few minutes to adjust / relearn.
>>However, be warned that you may get an itch to build more bikes... :)
>>
>>Have fun,
>>
>>Vi
>>
>>
>>
>>>________________________________
>>>From: Rhisiart Gwilym <Rhisiart@xxxxxxxxxxxxxx>
>>>To: python@xxxxxxxxxxxxx
>>>Sent: Sunday, July 31, 2011 1:34 PM
>>>Subject: [python] Re: AW: Re: Questions about Python-Trike geometry (project
>>>similar to Howard Stevens foldable Python trike)
>>>
>>>Hi Patrick,
>>>
>>>Well since I wrote, I've put the trike back-end back on my Python, just to
>>>have another think about it.
>>>
>>>It rides really well, and I have literally instant control; had it from the
>>>very first try out in fact, and went out on the road in traffic that first
>>>day.
>>>
>>>So what I'm doing now is putting a brake on the front wheel (I hadn't done
>>>that before) and I'm fixing a method to pull on both back brakes by a single
>>>hand lever. I may also try two brakes on the front wheel, operated by both
>>>hands, if the back brakes are just hopeless. I'll report results.
>>>
>>>I must say too that being able to bank all of the trike, except the
>>>rear-wheels frame, into bends, just like on the bike, is a real plus. (Erik
>>>Wannee's training back-end photo shows you exactly the design principle) It
>>>feels just like riding the bike, except that you have those brawny
>>>handle-bars, fixed to the back end, to push down/pull up on. I find that I
>>>do both at once when I feel myself going over. Just like pushing frantically
>>>against the ground with your stretched fingertips, but so powerful by
>>>comparison that you can stop all fall-overs dead before they get going.
>>>
>>>And I've already noticed, even on my fairly short total time on the banking
>>>trike that there is indeed a training effect for staying balanced, so that
>>>you begin to be able to lift your hands slightly off the bars for a few
>>>metres at a time. I suspect that with plenty of use of the trike I should be
>>>able to ride the bike with confidence, before long. You can see from the
>>>videos that there's a knack; that first-time riders suddenly get it. That's
>>>the magic moment that I'm shooting for!
>>>
>>>It does occur to me, though, that since we've all made our Pythons
>>>ourselves, to no standard design, might it be that subtle, quite small
>>>variations in bike geometry make all the difference between an easy,
>>>sweet-riding bike where you get the knack easily and within minutes, and a
>>>really tough dog? I seem to have made a tough dog. Anyone got any ideas
>>>about that, based on experience with several slightly differing geometries?
>>>
>>>Hwyl, Rh
>>>
>>>> Are you saying that you abandoned a beautifull trike design because of
>>>> rear wheel skiding when braking? I want to build a python trike myself, so
>>>> I wonder why you would worry about it. I mean, if just the front wheel is
>>>> enough for braking, then why bother about the rear? My two wheel Python
>>>> doesn't even have a rear brake. Or is it a safety concern? Though, you
>>>> could always fit multiple brakes on just the front.
>>>> Please let me know you thoughts,
>>>> Patrick
>>>>
>>>============================================================
>>>
>>>This is the Python Mailinglist
>>>
>>>//www.freelists.org/list/python
>>>
>>>Listmaster: J端rgen Mages jmages@xxxxxx
>>>
>>>To unsubscribe send an empty mail to python-request@xxxxxxxxxxxxx
>>>with 'unsubscribe' in the subject field.
>>>
>>>============================================================
>>>
>>>
>>>
>>>
>>
>>------------------------------
>>
>>Date: Mon, 1 Aug 2011 21:48:49 +0100
>>From: Rhisiart Gwilym <Rhisiart@xxxxxxxxxxxxxx>
>>Subject: [python] Re: AW: Re: Questions about Python-Trike geometry (project
>>si
>>
>>Many thanks, Vi. I'll take this on board and see
>>what happens. Trouble with me is that I just keep
>>falling over on the bike, and -- even on grass --
>>after a while it just gets too painful and
>>abrasive. Very exhausting too, for some reason.
>>But I am encouraged by the slow sneaking up of
>>the knack as I ride the trike and lift my hands
>>just off the bars for ever-longer moments.
>>Unlike your fantastic productivity, Vi, I'm very
>>slow at getting things re-made. So I think my
>>first line of attack is going to be to see
>>whether I can learn to balance the tilting trike
>>with the help of the fixed back-end, and then
>>when I think that I've got it I'll put the bike
>>back-end back on -- and see...
>>
>>Cheers all, Rh.
>>
>>>Hi Rhisiart,
>>>
>>>Since our bike/trike experiments are quite
>>>similar, I would to suggest the following:
>>>
>>>1. If pivot angle is higher than 60, find
>>>smaller wheels to try lower angles since you now
>>>have front brake. In my case, I went up from 48
>>>deg... If there is a quick way to raise your
>>>seat, bring it as high as you can. Use sticks
>>>if you can't reach the ground.
>>>
>>>2. Take off with fingers / sticks lightly
>>>resting on the ground (no leaning), and with as
>>>much pedaling force as you can without inducing
>>>steer (same trick to start with hands in the
>>>air). While training new riders, I obverse that
>>>they don't pedal hard enough and instead focus
>>>more on balancing and end up getting out of
>>>balance (I did the same but just couldn't see
>>>it). If you can "consciously" get some momentum
>>>going, your body/brain will amazingly take care
>>>of the rest... See my shaky
>>>and hesitant takeoff
>>><http://www.youtube.com/watch?v=6yBjSGL_pd8#start=0:00;end=0:07;autoreplay=true;showoptions=true>http://www.youtube.com/watch?v=6yBjSGL_pd8#start=0:00;end=0:07;autoreplay=true;showoptions=true
>>>
>>>3. Once you learn to take off, you can take all
>>>the time you want with other riding aspects, and
>>>different configurations (levels of difficulty).
>>> Switching configurations / bikes can take a few
>>>minutes to adjust / relearn. However, be warned
>>>that you may get an itch to build more bikes...
>>>:)
>>>
>>>Have fun,
>>>
>>>Vi
>>>
>>>
>>>From: Rhisiart Gwilym <Rhisiart@xxxxxxxxxxxxxx>
>>>To: python@xxxxxxxxxxxxx
>>>Sent: Sunday, July 31, 2011 1:34 PM
>>>Subject: [python] Re: AW: Re: Questions about
>>>Python-Trike geometry (project similar to Howard
>>>Stevens foldable Python trike)
>>>
>>>Hi Patrick,
>>>
>>>Well since I wrote, I've put the trike back-end
>>>back on my Python, just to have another think
>>>about it.
>>>
>>>It rides really well, and I have literally
>>>instant control; had it from the very first try
>>>out in fact, and went out on the road in traffic
>>>that first day.
>>>
>>>So what I'm doing now is putting a brake on the
>>>front wheel (I hadn't done that before) and I'm
>>>fixing a method to pull on both back brakes by a
>>>single hand lever. I may also try two brakes on
>>>the front wheel, operated by both hands, if the
>>>back brakes are just hopeless. I'll report
>>>results.
>>>
>>>I must say too that being able to bank all of
>>>the trike, except the rear-wheels frame, into
>>>bends, just like on the bike, is a real plus.
>>>(Erik Wannee's training back-end photo shows you
>>>exactly the design principle) It feels just like
>>>riding the bike, except that you have those
>>>brawny handle-bars, fixed to the back end, to
>>>push down/pull up on. I find that I do both at
>>>once when I feel myself going over. Just like
>>>pushing frantically against the ground with your
>>>stretched fingertips, but so powerful by
>>>comparison that you can stop all fall-overs dead
>>>before they get going.
>>>
>>>And I've already noticed, even on my fairly
>>>short total time on the banking trike that there
>>>is indeed a training effect for staying
>>>balanced, so that you begin to be able to lift
>>>your hands slightly off the bars for a few
>>>metres at a time. I suspect that with plenty of
>>>use of the trike I should be able to ride the
>>>bike with confidence, before long. You can see
>>>from the videos that there's a knack; that
>>>first-time riders suddenly get it. That's the
>>>magic moment that I'm shooting for!
>>>
>>>It does occur to me, though, that since we've
>>>all made our Pythons ourselves, to no standard
>>>design, might it be that subtle, quite small
>>>variations in bike geometry make all the
>>>difference between an easy, sweet-riding bike
>>>where you get the knack easily and within
>>>minutes, and a really tough dog? I seem to have
>>>made a tough dog. Anyone got any ideas about
>>>that, based on experience with several slightly
>>>differing geometries?
>>>
>>>Hwyl, Rh
>>>
>>>> Are you saying that you abandoned a beautifull
>>>>trike design because of rear wheel skiding when
>>>>braking? I want to build a python trike myself,
>>>>so I wonder why you would worry about it. I
>>>>mean, if just the front wheel is enough for
>>>>braking, then why bother about the rear? My two
>>>>wheel Python doesn't even have a rear brake. Or
>>>>is it a safety concern? Though, you could
>>>>always fit multiple brakes on just the front.
>>>> Please let me know you thoughts,
>>>> Patrick
>>>>
>>>============================================================
>>>
>>>This is the Python Mailinglist
>>>
>>><//www.freelists.org/list/python>//www.freelists.org/list/python
>>>
>>>Listmaster: Jí[rgen Mages <mailto:jmages@xxxxxx>jmages@xxxxxx
>>>
>>>To unsubscribe send an empty mail to
>>><mailto:python-request@xxxxxxxxxxxxx>python-request@xxxxxxxxxxxxx
>>>with 'unsubscribe' in the subject field.
>>>
>>>============================================================
>>
>>
>>------------------------------
>>
>>Date: Mon, 01 Aug 2011 22:57:43 +0200
>>From: Gerald <bepb@xxxxxx>
>>Subject: [python] Re: AW: Re: Questions about Python-Trike geometry (project
>>si
>>
>>Hi,
>>I made good experience with 48 degree pivot angle.
>>Even more than with the two wheel configuration, the front brake is the
>>most useful brake.
>>Much more powerful because with the trike you don't risk falling if he
>>front wheel slips.
>>
>>The rear brakes are not only much less effective, but also lead to
>>unusual reactions of the bike if not applied symmetrical.
>>
>>Normally, one would expect that the bike will tend to the right if the
>>right rear break is applied, but it is different with my python trike. I
>>use the break on the right rear wheel, the impulse of the python trike
>>is to go to the left. And the other way around.
>>Actually the rear part turns to the right, but in this pushing the pivot
>>to the right, which makes the front part of the bike turn left. This
>>seem to get more pronounced if the track is more wide.
>>
>>Somehow having separate breaks for the left and right rear wheel - as I
>>have on the trike - does not make much sense. And it is obviously only
>>possible if you run a coaster brake on the front wheel.
>>
>>I include, an obviously outdated, picture of my python trike from last
>>winter, showing the narrow track version:
>>
>>
>>
>>Gerald
>>
>>
>>
>>
>>
>>
>>On 1.8.11 15:12 , Patrick van Gompel wrote:
>>> Ah, thanks for your explanation! Yes, having just rear brakes on a
>>> trike is not a good idea. A front brake will make all the difference.
>>>
>>> I can't help you with the geometries, as I haven't tried (many)
>>> different setups.
>>> My 'magic moment' was there when I temporarily attached two wheelchair
>>> wheels on my Python. Although the construction was weak and the track
>>> was too small, it did give me a sudden insight of how the Python was
>>> steered. On this trike the cycling was very easy. It appeared to me
>>> that steering wasn't the actual problem, but keeping balance was. That
>>> might sound like an open door, but when you steer on a Python your
>>> centre of gravity is actually shifted to the outside of the corner.
>>> That means that you have to lean more than on a conventional bike. I
>>> still have problems with that when I make sudden sharp corners.
>>>
>>> Thanks,
>>> Patrick
>>>
>>>
>>> > Date: Sun, 31 Jul 2011 21:34:39 +0100
>>> > To: python@xxxxxxxxxxxxx
>>> > From: Rhisiart@xxxxxxxxxxxxxx
>>> > Subject: [python] Re: AW: Re: Questions about Python-Trike geometry
>>> (project similar to Howard Stevens foldable Python trike)
>>> >
>>> > Hi Patrick,
>>> >
>>> > Well since I wrote, I've put the trike back-end back on my Python,
>>> > just to have another think about it.
>>> >
>>> > It rides really well, and I have literally instant control; had it
>>> > from the very first try out in fact, and went out on the road in
>>> > traffic that first day.
>>> >
>>> > So what I'm doing now is putting a brake on the front wheel (I hadn't
>>> > done that before) and I'm fixing a method to pull on both back brakes
>>> > by a single hand lever. I may also try two brakes on the front wheel,
>>> > operated by both hands, if the back brakes are just hopeless. I'll
>>> > report results.
>>> >
>>> > I must say too that being able to bank all of the trike, except the
>>> > rear-wheels frame, into bends, just like on the bike, is a real plus.
>>> > (Erik Wannee's training back-end photo shows you exactly the design
>>> > principle) It feels just like riding the bike, except that you have
>>> > those brawny handle-bars, fixed to the back end, to push down/pull up
>>> > on. I find that I do both at once when I feel myself going over. Just
>>> > like pushing frantically against the ground with your stretched
>>> > fingertips, but so powerful by comparison that you can stop all
>>> > fall-overs dead before they get going.
>>> >
>>> > And I've already noticed, even on my fairly short total time on the
>>> > banking trike that there is indeed a training effect for staying
>>> > balanced, so that you begin to be able to lift your hands slightly
>>> > off the bars for a few metres at a time. I suspect that with plenty
>>> > of use of the trike I should be able to ride the bike with
>>> > confidence, before long. You can see from the videos that there's a
>>> > knack; that first-time riders suddenly get it. That's the magic
>>> > moment that I'm shooting for!
>>> >
>>> > It does occur to me, though, that since we've all made our Pythons
>>> > ourselves, to no standard design, might it be that subtle, quite
>>> > small variations in bike geometry make all the difference between an
>>> > easy, sweet-riding bike where you get the knack easily and within
>>> > minutes, and a really tough dog? I seem to have made a tough dog.
>>> > Anyone got any ideas about that, based on experience with several
>>> > slightly differing geometries?
>>> >
>>> > Hwyl, Rh
>>> >
>>> > >Are you saying that you abandoned a beautifull trike design because
>>> > >of rear wheel skiding when braking? I want to build a python trike
>>> > >myself, so I wonder why you would worry about it. I mean, if just
>>> > >the front wheel is enough for braking, then why bother about the
>>> > >rear? My two wheel Python doesn't even have a rear brake. Or is it a
>>> > >safety concern? Though, you could always fit multiple brakes on just
>>> > >the front.
>>> > >Please let me know you thoughts,
>>> > >Patrick
>>> > >
>>> > ============================================================
>>> >
>>> > This is the Python Mailinglist
>>> >
>>> > //www.freelists.org/list/python
>>> >
>>> > Listmaster: Jürgen Mages jmages@xxxxxx
>>> >
>>> > To unsubscribe send an empty mail to
>>> > python-request@xxxxxxxxxxxxx
>>> > with 'unsubscribe' in the subject field.
>>> >
>>> > ============================================================
>>> >
>>
>>
>>
>>
>>------------------------------
>>
>>End of python Digest V9 #118
>>****************************
>>
>>
>
>
>
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