Nojapyöräfoorumi

Jarcco kirjoitti:

Jarcco kirjoitti:

paul_n kirjoitti:

Hi jarcco

So wooden mock-up sees the light of day ?

Wood base sits rims about right height from ground [ as no tyres fitted ] seat almost 20" as can be seen by level with top of rims.

Wood represents 1.5" sq frame tubing , single side mounted rear wheel so offset from front wheel groovy ? or what ...

Wrong front fork need to get rid of axle offset AND move wheel closer to seat to allow pedals to be closer to seat as well.

So question is what are we trying to achieve here ?

a) FWD - should be possible

b) seat height less than PDQ - about 5" as shown in picture

c) my own build 2 wheeler - hmmm

You can see Clox [ clone of ZOX [ neat hey ? ]] as front wheel further forward so pedals must be further forward than PDQ's as I need space for wheel to turn.

Which means seat must be further forward as well.

So question is what are we trying to achieve here ?

a) FWD - should be possible

b) seat height more than Python - about 10" - out the dirt !!!

c) my own build 2 wheeler - hmmm

So what to change I think main frame under seat needs much less slope , so add some height to rear wheel mounting and add some depth to small piece at other end of main frame piece.

If I don't get that tube almost horizontal then seat will become higher as it moves towards forks ?

All for now still pondering Paul

Hi

In case of Zox/Jive clone style, I suggest shortening the main frame so seat and front wheel are closer. Then, a longer vertical part is required in the frame, like my design. So less slope under seat frame as you mean.

But if you build something like Vilijami presents, longer frame is ok. Then remote or under seat steering in needed.

Note 1, Fork does not must to be straight in FWD, but fork with rake guide roll must be positioned more backwards, that chain forces are compensated.
Note 2, Whatever fork you use, check trail value: http://yojimg.net/bike/web_tools/trailcalc.php

Ed. Add clarification.-jarcco

samuel kirjoitti:

Hi Paul and welcome.
Did You use the sticky thread DIY projektit listana on top of building list?

Yes this forum is full of very active builders unlike most of the USA/UK one's.

There are some very inovative builds on here.

regards Paul

Jarcco kirjoitti:

Hi

In case of Zox/Jive clone style, I suggest shortening the main frame so seat and front wheel are closer. Then, a longer vertical part is required in the frame, like my design. So less slope under seat frame as you mean.

The PDQ in the background is a SWB , SWB can give a lively twitchy ride.
I was hoping the Jive having a longer WB would be a bit more relaxing to ride ?

But if you build something like Vilijami presents, longer frame is ok. Then remote or under seat steering in needed.

Which bike is that ?

Note 1, Fork does not must to be straight in FWD, but fork with rake guide roll must be positioned more backwards, that chain forces are compensated.

I hoped if the fork was straight it would be easier to get the chain parallel to the fork legs ,and easier to measure the head tube angle ?

Note 2, Whatever fork you use, check trail value: http://yojimg.net/bike/web_tools/trailcalc.php

My Jive plans shows 67mm trail , is that what you have used ?

paul_n kirjoitti:

Jarcco kirjoitti:

Hi

In case of Zox/Jive clone style, I suggest shortening the main frame so seat and front wheel are closer. Then, a longer vertical part is required in the frame, like my design. So less slope under seat frame as you mean.

The PDQ in the background is a SWB , SWB can give a lively twitchy ride.
I was hoping the Jive having a longer WB would be a bit more relaxing to ride ?

That is not always true. Minor changes to geometry can give a great effect. PDQ looks shorter side SWB.
Avoid heel and wheel interference, cranks must be near steering axis, or much front of it.

paul_n kirjoitti:

Jarcco kirjoitti:

But if you build something like Vilijami presents, longer frame is ok. Then remote or under seat steering in needed.

Which bike is that ?

Vilijamis trike is at previous page: http://www.nojapyorafoorumi.fi/viewtopic.php?f=3&t=5113
You might be interested also: http://www.nojapyorafoorumi.fi/viewtopic.php?f=3&t=3552
http://tilting.org.za/bok/pedelec.html

paul_n kirjoitti:

Jarcco kirjoitti:

Note 1, Fork does not must to be straight in FWD, but fork with rake guide roll must be positioned more backwards, that chain forces are compensated.

I hoped if the fork was straight it would be easier to get the chain parallel to the fork legs ,and easier to measure the head tube angle ?

You are right, it makes things easier.

paul_n kirjoitti:

Jarcco kirjoitti:

Note 2, Whatever fork you use, check trail value: http://yojimg.net/bike/web_tools/trailcalc.php

My Jive plans shows 67mm trail , is that what you have used ?

Yes, 1,5 x tyre width works fine many cases. ( Maybe not Fatbikes )

Jarcco kirjoitti:

But if you build something like Vilijami presents, longer frame is ok. Then remote or under seat steering in needed.

Or Groundhugger style steering?

Hi all

Ok a big honey do list has given plenty of ' thinking time ' but little building time

I have tidied up the rear end so it looks neater and allows the main frame to be parallel to the ground :-

I have no idea where seat will end up , except prehaps further forward.

Realised I can raise the pedals considerably as I am comfortable with them at least 15 cm above the seat , however I can't sort the front end out until I have a set of forks ?

So cut some steel ! the piece for the rear wheel to mount on , a over long main boom and a piece to mount the head tube in also over long.

I cleaned up my truncated forks to lengthen the legs.

Progress soon I hope.

all the best Paul

A FWD fork in the making ?

We need to modify some front forks to take a rear wheel ? The crude way is to spread them and then try and bend the ends back parallel and with enough clearance for both a cassette and or a disc rotor.
The smarter way is to cut them and add stuff ?
So cutting them just after the brake studs got rid of the fork's rake , as I want the legs as straight as possible , because the chain needs to run parallel to them to reduce pedal steer/torque
I have plug welded some stubs into the fork ends to locate the new piece's of leg tubing and reinforce the joint.

This looks about the best tyre/crown clearance I can get , there is still about 3mm of brake shoe adjustment to the right and lot's to the left.

I have ordered some 4mm plate to make these card templates from 1 each side then a short length of straight leg tubing will be spliced in to the existing tube's/stubs and with a 45' angle cut at the other end will meet these plates ...

Hopefully job's a good un ?

anyone spot the non deliberate mistake ?

I should NOT be left unsupervised !

Casette is in wrong side? If brake pin are backside on the fork, chain hits it.

This is my fork jig.

Hi there

Yes I will need to build a jig like that to weld it together.
Thanks for the picture

Paul

Vilijami kirjoitti:

Casette is in wrong side? If brake pin are backside on the fork, chain hits it.

You probably noticed this?
The easiest way is to extend the cut fork with thick flat steel, like Toxy ZR:

BTW, Raptobike fork is reasonably-priced:
https://www.raptobike.com/carbon-stoel-large-21

Hi all

thanks for the help , in the style of your builds I am trying to make my own FWD fork.

However the Raptobike would be a good second choice should I fail

I have the steel on order 400mm x 50mm x 4mm hopefully it will be strong enough.

Paul