Outer Limits 4x4 Board

so i am making a billy-kart for a competition within my scout group, and we have an approx $100 limit.

i want to have car style steering and i know how all the links need to go together, but having never pulled apart a steering box, im at a loss as to how to connect the steering shaft to the links. if i had more funds, id just whack a steering box on and be done with it, but as im limited in that area i would love to know how i could go about building my own basic one.

clearly it doesnt have to be anything massive over engineered, but im just not quite sure where to start... any pointers would be tops


cheers
Macca

look up the 'off road fabrication network' forum. there are pages of info on getting billy cart steering to work - for red bull events.

Its easy enough, but you do need to get the KPI right, and castor for it to turn nicely and not kill you above 20k's. In the same way a bicycle would handle poorly if the stering stem was vertical.

Bah, just use bellcrank. You dont feel more alive than hurtling down a hill with nothing but a block of wood pressing on the rear lawnmower wheel as brakes and good ol bellcrank steering(ish).

Racing carts just have 1/4 turn lock-lock steering. Very simple, quick and responsive. No need for 3-4 turn lock-lock steering like a car.

You just need a shaft, running on a couple of bearings or bushes, with a steering wheel boss on one end and a metal plate about 3" high on the other end. The steering knuckles just bolt to the metal plate.

Hope that all makes sense???

You prob wont get much simpler than this: http://www.diygokarts.com/kart-plans/st ... ndles.html for real steering!

But nothin beats one single pivot point on a solid shaft with a bit of rope (or feet!) to steer

PJ.zook wrote:Bah, just use bellcrank. You dont feel more alive than hurtling down a hill with nothing but a block of wood pressing on the rear lawnmower wheel as brakes and good ol bellcrank steering(ish).

Lets add some real excitement and replace the lawnmower wheels with tractor wheel bearings. Hardly even need bellcrank foot operated steering just a flick of the body and away you go. Made these years ago, great fun but then tended to understeer a fair bit from memory.

mike_nofx wrote:You prob wont get much simpler than this: http://www.diygokarts.com/kart-plans/st ... ndles.html for real steering!

But nothin beats one single pivot point on a solid shaft with a bit of rope (or feet!) to steer

Thast fine, just rotate them back for castor

bru21 wrote:

mike_nofx wrote:You prob wont get much simpler than this: http://www.diygokarts.com/kart-plans/st ... ndles.html for real steering!

But nothin beats one single pivot point on a solid shaft with a bit of rope (or feet!) to steer

Thast fine, just rotate them back for castor

Wouldnt that cause one front wheel to lift in air when you steer front wheels?

bru21 wrote:

mike_nofx wrote:You prob wont get much simpler than this: http://www.diygokarts.com/kart-plans/st ... ndles.html for real steering!

But nothin beats one single pivot point on a solid shaft with a bit of rope (or feet!) to steer

Thast fine, just rotate them back for castor

And angle them in slightly at the top for camber.



You want negative camber and positive caster.

PJ.zook wrote:

bru21 wrote:

mike_nofx wrote:You prob wont get much simpler than this: http://www.diygokarts.com/kart-plans/st ... ndles.html for real steering!

But nothin beats one single pivot point on a solid shaft with a bit of rope (or feet!) to steer

Thast fine, just rotate them back for castor

Wouldnt that cause one front wheel to lift in air when you steer front wheels?

yes. but you wouldn't need a great deal of castor or camber.
i'd be trying to get a ackerman in the mix aswell

Built one for offroad racing about 10 years ago an used a cut down escort rack an pinion
Also had subaru disc brakes mated to HQ hubs on the rear an full indipendant suspension ,
Gave us a fairly hairy ride at about 120kms down through the pine plantations near mount cole
Also cost me a kneecap when a tree stepped out
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Dont forget to check the scrub radius and the negative offset amount.

Bazzle

Might be an idea to factor in your ackerman angles too

Sheesh - it's a billy cart. If it steered well it wouldn't be as much fun

Hmm - street luge

Paul

i know what your saying paul, but this billy kart is going on a 1km long course that is offroad... steering would worry me a lot less if it was just for down the street. high speeds and trees dont mix i have found!

macca81 wrote:i know what your saying paul, but this billy kart is going on a 1km long course that is offroad... steering would worry me a lot less if it was just for down the street. high speeds and trees dont mix i have found!

Just duplicate that from a comp kart then. All of the angles are worked out.

Note the dimensions used also, especially things like the distances and misalignment of the tie rod to the king pin etc, they are all related to the ackerman. For the castor, if it has a solid rear axle then wind it on as you will need it to make it handle, otherwise just add a couple of degrees for self centering. If you have a solid rear axle then also check the measurements of your front scrub radius, if the rear wheels will spin at different speeds then again this is a lot less important. Camber.... you may not want neg camber, just see how much it flexs when somebody gets in, or setup with somebody in it. They wont exactly generate a lot of grip on dirt, but what will make a significant difference to the handling is the weight bias front to rear - you need to get this exact!