Rennies Trike

[steven brock]

I tried to put least weight as possible on my front trying to match weight applied to bike front wheel, I'm making girders for my other trike as personally believe anything heavier than a bike needs something more substantial, I bet you could make your own girders check this guy out I think he great

http://youtu.be/xQZ8TIeZnws

[andyrennison]

That's worth thinking about Steve. Not sure of i have the skills though!

[steven brock]

You made the frame! Don't underestimate yourself buddy

[andyrennison]

Cheers MM, feeling better for losing the weight, must admit!. Done some work on the rear seat fixing and suspension,will take some pics tomorrow. Not sorted the front end issue yet Steve. Done a lot of research, im not keen on fork extenders having talked to a few folk who make them - the general view was "DONT DO IT". so its either a different longer set of forks and associated stuff or alter the frame. $$$ say alter the frame. Going to take a good look at it tomorrow.

andy what forks are you using,, what lenth /diam, ar they ,

hi mike. Current forks are 790 from wheel centre to the top of the fork. Needs to be about 845mm 37mm diam

[andyrennison]

Well, Steve set me off on a journey!  I'm going to have a go at a set of leading link forks and make my own yolks.  Nothing too fancy, just enough to look ok and give me decent handling. My reading seems to indicate a trail of about 1.5" will be ok.  Going to get a set of shocks off evil bay then start from there

[Manky Monkey]

When you first came here you didn't think you could build a trike -now there's no stoppng you!

[andyrennison]

Ha ha. Its not turned a wheel yet Andy, and its taking forever, still, the journey is more important than arriving hey!.

This is the general plan for the leading links. The part I am going to need some advice on ith the pivot at the teal coloured blob.

The main legs will be CDS, as will the rockers and bail. Yolks will be 1/2" steel plate, fork legs welded onto the lower yolk, and both downwards through the upper yolk into a net welded in place indide the top of the fork leg.  Plates below the rockers will carry the clipers, and the shocks will mound into saddles so the shocks runs parallell to the fork legs.

I will fabricate some form of square peg to weld into the bottom of the fork legs, which can then locate between two plates welded to the rockers. Need some form of bearing / pivot in there, I remember comments about needing brass bushes or some such but no idea how to do that. maybe I could use some sort of bearing

[Olds]

The man has a plan
If you go with this, please take lots of pics as you go along. I'm sure others will be very interested (I know I am).
One thought. If the legs are welded to the lower yoke and bolts through the upper one into threads in the top of the legs, how do you adjust the distance between the yokes to adjust the steering head bearings, or do you make the steering stem long enough to take an adjusting nut plus lock nut plus a bit of clearance under the top yoke?

[triker_Chewie]

ssome good pictures here,
http://threewheelsmad.tripod.com/leading_link_forks.htm

[andyrennison]

Hi ON. The plan is to use an independent adjustment nut. I have a high tank so the extra clearance will be welcome. Onetonmcgoo on you tube bolts his girder forks to the SIDE Of the yokes with straps. The upper straps are longer than the lower ones allowing the rake to be tweaked slightly by moving the whole assembly up an down.
good link that Chewie, again lots of ideas, l had a good look at that

[steven brock]

That onetwomango fella has great vids it all look so simple..  I'm not far off showing mine off soon

[ByzMax]

I like leading links.


Some observations.

Caliper bracket needs to be above the rocker arm.

The caliper bracket must be fully floating (must be free to rotate when the wheel spindle is done up)

You need to fix the caliper bracket to the fork leg using a link bar (use a rose joint each end) not the rocker or you will get a torque reaction form the rocker arm under braking.

The bar that links them should run parralel to the rocker.

Pivots could be Oilite Bronze, Dx  or needle bearings.

I'd not weld the fork leg to the lower yoke. It's a stress raiser and may adversely affect the metalurgy of the material you are using.

It also makes getting the alignment of the pivots harder to set.

Click on the link to see how Haggis built a set. The link takes you to britchopper.

http://www.britchopper.co.uk/forum/viewtopic.php?f=46&t=26673&hilit=hopw+not&start=125

Hope that helps

[andyrennison]

Cheers byzmax. Not sure what you mean by fully floating but i will take a look at the link etc. Early days in the planning, all advice is very welcome indeed

[andyrennison]

Caliper bracket needs to be above the rocker arm.

.........

http://www.britchopper.co.uk/forum/viewtopic.php?f=46&t=26673&hilit=hopw+not&start=125

Hope that helps

Hi ByzMax. That is a fantastic article, credit to Haggis on the forks, and lots of great ideas there. One thing I am still unclear on is the quote above. In the build shown the caliper is below the rocker arm, which puts the link bar into compression under braking. Is that why you said the caliper shoiuld be above, the the link bar would be under tension rather than compression ?

[andyrennison]

Not sure what diameter stantions to go for. Words of wisdom anyone?