[python] Re: Thanks Chris! Any everyone else.
- From: Ivan van Hoof <zl3tiv@xxxxxxxxx>
- To: "python@xxxxxxxxxxxxx" <python@xxxxxxxxxxxxx>
- Date: Fri, 5 Apr 2013 06:36:46 +1300
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> 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@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 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 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
>> To: 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> 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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