[python] Re: Thanks Chris! Any everyone else.
- From: chris williams <chriswilliams67@xxxxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Fri, 5 Apr 2013 09:07:51 -0400
Has anyone tried just having very long vertical rear dropouts? By moving
the rear wheel up or down in the drop outs you would effectively change the
pivot angle :-)
Chris.
On Thu, Apr 4, 2013 at 9:12 PM, John Lewis <john.lewis@xxxxxxxxxxxxxxxx>wrote:
> G'day Ivan and the list,
>
> Been following with interest. I've built a heap of bikes but yet to get a
> Python done. I'm looking at a trike version I think.
> Regards the seat ply. I found that 6mm 5 ply bends one direction but not
> the other. I cut two strips with the main lot of grains across so it bends
> and used exterior white glue to put it together in a simple jig. It made a
> beautiful seat. I made a home brew version of a Ventisit pad for it.
>
> BTW My XYL just returned from a trip round NZ on the Dawn Princess. She
> loved it.
> Might catch up on air.
>
> John.
>
> VK6JL
>
>
>
> Ivan van Hoof wrote:
>
>> Hi Kelvin
>>
>> Haven't see you for years! Not since you guys move to the north island.
>> Rung your lovely wife last night and I will talk to you over the weekend by
>> twisted pair. Lots of questions re bikes and a catch up too. Very small
>> world.
>>
>> Ivan van Hoof
>>
>> Sent from my iPad
>>
>> On 3/04/2013, at 10:51 PM, Kelvin Arthur <kelvin.arthur@xxxxxxxxx<mailto:
>> kelvin.arthur@gmail.**com <kelvin.arthur@xxxxxxxxx>>> wrote:
>>
>> Hi Ivan
>>>
>>> Nice to have another Kiwi keen to do the python thing. I have built one
>>> here down under, it started out as something of a mongrel and was
>>> progressively modified over about a year to the final version for now.
>>> My thoughts, having read a lot on the web, built, and riden. Don't
>>> worry about suspension, if you're really concerned about a soft ride, build
>>> a textile seat (some sort of sling arrangement), this softens the ride no
>>> end without sacrificing too much in the power department. It is also easy
>>> to make and adjust. I built a curved wooden seat for a Bachetta clone,
>>> rear wheel drive recumbent recently, while a great seat, MUCH more work
>>> than the sling and it makes the position of it much more critical.
>>> As for pivots, I tried steering ball ends, complete disaster, I then
>>> went to a cup and cone bb, less of a disaster, still not very good. I then
>>> got 2, 12mm male tie rod ends and never looked back, easier to construct
>>> for, gives you about 2 degrees of angle adjustment each way and plenty
>>> strong enough. The final version of pythonui has an adjustable bb at the
>>> front for leg length, a sling seat, and even with a 3 metre wheel base
>>> (yes, it's a monster!) and my 4 year old boy in the back, I never had the
>>> feeling that the pivot wasn't up to the task. My python was transported by
>>> car a lot, being able to undo 2 bolts, and have the bike split was a real
>>> bonus, and allowed me to get it into my hatchback with ease, even the big
>>> version.
>>>
>>> On the gears front, my early version had a derailer, while functional, I
>>> never looked back after getting an in hub gear. It's only a shimano 3
>>> speed, but it's enough. Using an 8 speed hub gear with a coaster brake
>>> would have been a real dream for me, but I built with no budget, scrounging
>>> what I could.
>>> When you first build it, build it to be crashed, a LOT, it will save you
>>> the heartache of having to repair your lovely work!
>>>
>>> My few cents worth, and sorry for the novel.
>>>
>>> Kelvin (yes, it turns out it is a very small world after all!)
>>>
>>> Sent from my iPad
>>>
>>>
>>>
>>> On 3/04/2013, at 21:46, Patrick van Gompel <patrick_van_gompel@hotmail.*
>>> *com <patrick_van_gompel@xxxxxxxxxxx> <mailto:patrick_van_gompel@**
>>> hotmail.com <patrick_van_gompel@xxxxxxxxxxx>>> wrote:
>>>
>>> Hello,
>>>>
>>>> The option I use for an adjustable pivot point is a 'rod end joint'.
>>>> You can see it here: http://cycle.free-creativity.**
>>>> com/images/python5.jpg<http://cycle.free-creativity.com/images/python5.jpg>
>>>> The rod ends are protected by a rubber boot. The cheapest and best seller
>>>> I have found is: http://mcgillmotorsports.co.**
>>>> uk/index.php?act=viewCat&**catId=25<http://mcgillmotorsports.co.uk/index.php?act=viewCat&catId=25><
>>>> http://mcgillmotorsports.co.**uk/index.php?act=viewCat&**catId=25<http://mcgillmotorsports.co.uk/index.php?act=viewCat&catId=25>>
>>>> They have 3 types, but I prefer the 'High Performance'.
>>>>
>>>> At the moment I use M12 size, which is strong enough, but for my next
>>>> project I am going for M14 as I am building a utility trike and needs to be
>>>> very strong.
>>>> Not sure how many degrees I can adjust the pivot, but it depends on
>>>> your design (the distance between the two rod ends and the size of them).
>>>> If you need detailed info about those rod ends, like thread length or max.
>>>> angle; it's available (just ask).
>>>> Though, you can't adjust the pivot 'on the go'. You need to detach the
>>>> front and rear part and use shims to fit the rod ends on the pivot axle
>>>> without play.
>>>>
>>>> Ivan, I don't think you need suspension. Of course, my big apple 26"
>>>> tires are more comfortable than racing tires, but it is like you compare a
>>>> ride on a mountainbike with fat tires to that of a racing bike, I think. My
>>>> experience with recumbents in general is that a nice seat with a good
>>>> cushion does also give you a more comfy ride.
>>>>
>>>> Greetings,
>>>> Patrick
>>>>
>>>> ------------------------------**------------------------------**
>>>> ------------
>>>>
>>>> Date: Wed, 3 Apr 2013 10:53:21 +0300
>>>> Subject: [python] Re: Thanks Chris! Any everyone else.
>>>> From: balamber@xxxxxxxxx <mailto:balamber@xxxxxxxxx>
>>>> To: python@xxxxxxxxxxxxx <mailto:python@xxxxxxxxxxxxx>
>>>>
>>>>
>>>> Hi Ivan,
>>>>
>>>> A working adjustable pivot is technically very difficult to do in my
>>>> opinion. I tried to build a test bike with an adjustable pivot to test
>>>> different bike geometries but it tended to buckle all the time. I would
>>>> suggest that if you really need to change the bicycle geometry, instead of
>>>> an adjustable pivot add front and/or back suspensions with a pretty large
>>>> range of adjustment and use them to raise/lower the front and rear of the
>>>> bike. This way you change the pivot angle as well.
>>>> If anyone has a good idea/mechanism of an adjustable pivot with a +/-
>>>> 15 degrees of range or even more please share it. Infinitely
>>>> adjustable/stepless adjustment preferred.
>>>>
>>>> That's my two cents.
>>>>
>>>> Tiha
>>>>
>>>>
>>>> On Wed, Apr 3, 2013 at 10:09 AM, Ivan van Hoof <zl3tiv@xxxxxxxxx<mailto:
>>>> zl3tiv@xxxxxxxxx>> wrote:
>>>>
>>>> That sounds like one nice seat! Bending ply or snake ply, I will
>>>> have to make my seat out that stuff. Any thoughts on the main
>>>> pivot? I like the simple bottom crank design but I want a design
>>>> that is simple looking, sleek and adjustable angle by a few
>>>> degrees to account for other riders weights and lengths. Good to
>>>> see the group is active, very quick replies from you guys is great!
>>>> I have shown, told a few work mate and friends the web site and
>>>> they are keen to see me finish my python and ride it.( and a few
>>>> think am crazy.)
>>>> How smooth is the ride of these bike with 700c or 26 inch wheel
>>>> on the road( no off road) would I need suspension? I intend to
>>>> only use the bike for touring on the road. I'm thinking no
>>>> suspension to save weight.
>>>> Thanks guys for your help.
>>>>
>>>> Ivan van Hoof
>>>> ZL3TIV
>>>>
>>>> Sent from my
>>>> iPad==========================**==============================**
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