[python] Re: AW: Re: Questions about Python-Trike geometry (project similar to Howard Stevens foldable Python trike)

  • From: Rhisiart Gwilym <Rhisiart@xxxxxxxxxxxxxx>
  • To: python@xxxxxxxxxxxxx
  • Date: Mon, 1 Aug 2011 21:48:49 +0100

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

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