Nojapyöräfoorumi

Hi there
Sorry for the English

Can I ask a few questions about this build ?

I am going to build a FlevoTrike as I want a higher seat and narrower track than my current Python trike.

However for my Flevotrike I want to use the pivot angle and trail of Python trike to make it handle more Python like.

I have built a quick prototype re-using as many parts as I currently have , shown in picture above behind current trike and like you have been experimenting with elastomers.

I added a second elastomer because it tilted to fast with one and also with one elastomer the upper beam yawed left and right when riding adding unwanted steering input.

I see you have used springs as well , what did you end up with ?

What did you mean by elastomer memory ?

If I understand correctly you also limited the steering to about 45' , that would also make it more like my Python.

I also want the rear end narrow , you found @ 405mm track it handled better.

Did you consider the handle bars mounted on the steering part ? I feel safer on my Python riding like that.

regards Paul

paul_n kirjoitti: ↑29 Huhti 2021, 09:28

Hi there
Sorry for the English

Can I ask a few questions about this build ?

I am going to build a FlevoTrike as I want a higher seat and narrower track than my current Python trike.

However for my Flevotrike I want to use the pivot angle and trail of Python trike to make it handle more Python like.

I have built a quick prototype re-using as many parts as I currently have , shown in picture above behind current trike and like you have been experimenting with elastomers.

I added a second elastomer because it tilted to fast with one and also with one elastomer the upper beam yawed left and right when riding adding unwanted steering input.

I see you have used springs as well , what did you end up with ?

What did you mean by elastomer memory ?

If I understand correctly you also limited the steering to about 45' , that would also make it more like my Python.

I also want the rear end narrow , you found @ 405mm track it handled better.

Did you consider the handle bars mounted on the steering part ? I feel safer on my Python riding like that.

regards Paul

Well, sorry for the bad english

Elastomer is quick and cheap solution. Elastomer is spring and shock absorbers same time, movement is slow and this i mean elastomer memory.
Springs are bad solution too. Very good lean joint, must be make only for bearings, without any spring or elastomers.

Steering is limited, because it save steering elastomer. No other causes.

Foot steered bikes no need handle bars for steering. Handlebar only function is shifters and brakelevers repository.

Check this viewtopic.php?f=3&t=4948url There i modified Flevo steering geometry better than original Flevo or Python. Pivot angle is 45 degrees and trail is zero. This is brilliant!
Also Lean joint trail should be zero. Then driving is neutral and comfort.
You can see picture and understand what i mean for lean join trail.

Summary: In my wiew, both trails (steering and lean) should be zero and steering pivot angle 45 degrees. No springs or elastomers for steering or lean.

Hi Vilijami

Thanks for your prompt and comprehensive reply.

Summary: In my wiew, both trails (steering and lean) should be zero and steering pivot angle 45 degrees. No springs or elastomers for steering or lean.

Damm just paid a small fortune in Euro's for a set of 3 trike dampers !

Not sure how you measure the tilt trail ?

I want a narrow track so intended lowering the tilt pivot to about 15 cm from floor [ like Eric Wannee ], do you think this is not necessary either ?

Glad I have not cut any steel yet

regards Paul

paul_n kirjoitti: ↑30 Huhti 2021, 09:47

Not sure how you measure the tilt trail ?

I want a narrow track so intended lowering the tilt pivot to about 15 cm from floor [ like Eric Wannee ], do you think this is not necessary either ?

Glad I have not cut any steel yet

regards Paul

Tilt trail is line between two joints. In Flevo case it is steel balljoint center and elastomer center between line.

Eric Wannee lowering tilt joint, but it still too high, because joint line is horizontal and trail is infinite.
Better version is inclined line (between joints) which produces trail.

Do you understand what i try explain?

Hi Vilijami

Yes I think I do ?

A vertical line from the front axle to the ground , at the point it touches the ground a line through the steering axis also meets there AND a line through the tilt axis meets there ?

Did anyone build such a trike ?

Have you seen this ?

I do not understand why the bike with 75' behaves differently to the bike with 46' , 75' would seem to be better ?

He discusses it's development here :- https://www.velomobilforum.de/forum/ind ... ger.47922/

all the best Paul

paul_n kirjoitti: ↑30 Huhti 2021, 18:09

Hi Vilijami

Yes I think I do ?

A vertical line from the front axle to the ground , at the point it touches the ground a line through the steering axis also meets there AND a line through the tilt axis meets there ?

Did anyone build such a trike ?

Have you seen this ?

I do not understand why the bike with 75' behaves differently to the bike with 46' , 75' would seem to be better ?

He discusses it's development here :- https://www.velomobilforum.de/forum/ind ... ger.47922/

all the best Paul

A long term plan is build such trike. Steering (45 degrees and zero trail) is tested and approved.
Original Flevo steering tries fall down and lift up is heavy. Same feeling is in original tilt joint. Unfortunately i never modified tilt joint for zero trail, but someone sunny day....

75' pivot angle and large negative trail feels good idea for first, but its not necessarily. Steering must fall down lightly (but not heavily) when you tilt the bike/trike. Then handling is stabil and safe.

These all thoughts are my own opinions and experiences, not absolute truths.

Hi Vilijami

These all thoughts are my own opinions and experiences, not absolute truths.

Worth a whole book of theorising !

Only when things go wrong do we need someone to understand what happened

Paul

ps I may be a guinea pig then ?

Hi Vilijami

Where you thinking of trying to build a Flevo front like this ?

This is a 20" wheeled kid's bike rear end , seems to put a big gap between wheel and the horizontal frame member ?

Also the pedals are no as far forward as they are on a real Flevo [ handy for my mate who has no inside leg to talk of ]

The seat tube is a very small diameter for the main frame , the angled shiny bit is 2 seat posts welded together @ 45' I intended to bolt this inside the horizontal tube for speed and save welding gas

Paul

paul_n kirjoitti: ↑04 Touko 2021, 20:00

Hi Vilijami

Where you thinking of trying to build a Flevo front like this ?

It works, but most likely it is too flexible.

Vilijami kirjoitti: ↑04 Touko 2021, 20:59

paul_n kirjoitti: ↑04 Touko 2021, 20:00

Hi Vilijami

Where you thinking of trying to build a Flevo front like this ?

It works, but most likely it is too flexible.

I thought that was the idea with this drawing ?

I can live with flexible if it will work , only want a few miles out of it not a few years

Paul

paul_n kirjoitti: ↑05 Touko 2021, 00:21

I thought that was the idea with this drawing ?

Yep. But your shiny tube after triangle isn´t stiff enough = use bigger diameter tube instead that thin one.

Pastori kirjoitti: ↑05 Touko 2021, 10:52

paul_n kirjoitti: ↑05 Touko 2021, 00:21

I thought that was the idea with this drawing ?

Yep. But your shiny tube after triangle isn´t stiff enough = use bigger diameter tube instead that thin one.

It is a seat post and welded to another inside the blue tube.

It will be sleeved by another one on the outside when I have sorted out where the pivot needs to go.

With no suspension I had though of triangulating the chrome tube with the seat stays on the blue part, maybe another set of seat stays trimmed to fit?

Paul

paul_n kirjoitti: ↑05 Touko 2021, 00:21

I can live with flexible if it will work

It doesn’t get so bad, that it couldn’t be better rebuilt again.

Ok so made better mock up and fashioned a few more parts.

The wood is @ 45' to the horizontal frame and the threaded rod is @ 90' to the wood and almost at 0"/cm trail.

So the clamp rod joint is where the steering pivot will go.

I have salvaged a BB and very short seat tube inside is a short length of tubing and outside will be a length of seat tube over the chrome piece and joining it all together , looks like it might work.

Paul

I separate your project (from Vilijami´s) > to own discussion line.