Interesting Cheap Alternative to a Rack and Pinion Steering System

[SquidBonez]

Came across this video not too long ago, around the 1 minute mark he shows a very clever steering system he came up with that does the job of a rack and pinion system for a much cheaper price. Video is here:

This is not only cheaper but actually frees up potential frame designs. You wouldn't need to have the rack and pinion determine the width of the frame with this setup since you could make it as wide as you want. It can also be made with standard go kart components. Here's some closer pictures of the steering:


He claims there is very little to no bump-steer with this design. I'm surprised I don't see more people doing something like this.

 

[itsid]

uhm... that is how nearly all kart steerings in the 50s and 60s worked

pitman arm actuated a crossbar (usually afixed between the forward spindle arms .. since no suspension and such)
So yeah.. nothing new at all.."he came up with that"? well he must be really old then I guess
or he just reinvented a wheel

'sid

 

[Snaker]

That's similar to a lot of the modern snowmobiles.
As the suspension travel gets longer, having longer tie rods becomes a problem.
When the tie rod is the approximate length of the suspension arms, then bumpsteer is reduced.

 

[Kartorbust]

Pretty close to how trucks and SUVs were for years. I've read his build on minibuggy.net very interesting build I'll say that. Though last I knew, he was going to add a snowmobile engine to it but never updated it. https://www.minibuggy.net/forum/pro...co-dingo-transformed-into-suspended-kart.html

 

[SquidBonez]

uhm... that is how nearly all kart steerings in the 50s and 60s worked

pitman arm actuated a crossbar (usually afixed between the forward spindle arms .. since no suspension and such)
So yeah.. nothing new at all.."he came up with that"? well he must be really old then I guess
or he just reinvented a wheel

'sid

I know karts use pitman arms, but it usually goes from the steering shaft directly to the spindles right? I've never seen a setup like this that uses two pivots points in-line with the suspension pivots.

 

[itsid]

I know karts use pitman arms, but it usually goes from the steering shaft directly to the spindles right? I've never seen a setup like this that uses two pivots points in-line with the suspension pivots.

crossbar was the catchphrase there
here's a random old kart (a swoopster in this case)

see what I mean?

'sid

 

[Snaker]

crossbar was the catchphrase there
here's a random old kart (a swoopster in this case)
View attachment 124407
see what I mean?

'sid

Sid, your missing the key point.
Your picture is common on lots of things from carts to old snowmobiles to riding lawn mowers to farm tractors.
It works fine on any front end without suspension,
With a little suspension it can get by, long suspension- no good.
This diagram shows a similar design to the op photo.
The whole point of it is to get the tie rods terminated as close to the suspension pivots as possible rather than go all the way to machine center(or the other side)
This lets the steering movement stay the same no matter where the suspension is positioned.
Otherwise toe-in and toe-out changes throughout the suspension travel (ie, bump steer).

 

[SquidBonez]

View attachment 124416





Sid, your missing the key point.
Your picture is common on lots of things from carts to old snowmobiles to riding lawn mowers to farm tractors.
It works fine on any front end without suspension,
With a little suspension it can get by, long suspension- no good.
This diagram shows a similar design to the op photo.
The whole point of it is to get the tie rods terminated as close to the suspension pivots as possible rather than go all the way to machine center(or the other side)
This lets the steering movement stay the same no matter where the suspension is positioned.
Otherwise toe-in and toe-out changes throughout the suspension travel (ie, bump steer).

This is exactly what I was trying to describe. In order to eliminate/reduce bump steer the tie rods need to pivot on the same angle/point as the suspension. If you were just run the tie rods from the steering shaft directly to the spindles, you'd get bump steer. I've seen people do it this way (because it still technically "works") but it's not ideal and will result in some amount of bump steer. The solution from the original post not only allows for the use of relatively cheap tie rods as opposed to expensive steering racks, but also allows for a greater degree of design freedom (it also seems easier to set up correctly).

 

[itsid]

Sid, your missing the key point.

Not at all..
hence me adding the suspension note above

actuated a crossbar (usually afixed between the forward spindle arms .. since no suspension and such)

adding another linkage and pivot to support suspension w/o increasing bump steer isn't really an innovation.
as you correctly mentioned was used in countless examples over the time.
But I do agree that the polaris is indeed much closer to the setup on the kart squidbonez posted.
I added an image that spread the main idea of the crossbar-steering linkage w/o the suspension
(since it's what I had handy.. )

The key point of a rack and pinion isn't to support suspension either btw..
nor is it to reduce bump steer .. main reason for the need of a rack and pinion setup is it's gear reduction mostly..
to support easier steering on front heavy vehicles (way more cars have been built with a rack and pinion than karts )
the ease for suspension is a convenient side effect for sure.

Anyways... if I had had that polaris example on my computer I might have picked that,
since it's indeed the better comparision.

'sid

 

[madprofessor]

Just for fun, tacking on a couple of pics of my own homemade front suspension. It's got a 22-tooth #35 sprocket rolling across a piece of #35 chain welded flat, a homemade rack and pinion. What's funny is when finished it turned the wheels in the opposite direction, backwards thinking that's getting all too common with me. Instead of tearing it out, I just added a crossbar over the top of the gear and moved the chain. Super funny looking little house of angle irons sliding back and forth on the front of my cart, but me no care y'all. If there's a point to this, it's that the max maybe 150 degrees of steering wheel there would have been with a pitman arm wouldn't be enough to keep it stable at speed with that 10" steering wheel. This rack was designed for about 250 degrees stop to stop and works great. Also, notice the tierods' and A-arms' pivot points there at near to full right stop in the pic, on that extra-long-travel suspension. Very close, so very little bumpsteer even with the 17" tierods, which are mounted offset to the spindles to even them up with the A-arms, and also get correct ackermann. Would rather have had trailing-arm spindles instead of leading, so as not to crowd the insides of the tires, but not possible.

 

[Big Ezzie]

I know karts use pitman arms, but it usually goes from the steering shaft directly to the spindles right? I've never seen a setup like this that uses two pivots points in-line with the suspension pivots.

Well have you seen one like this

 

[Edwin Spangler]

Well have you seen one like this

No. Can I see more? Like, a lot more?

 

[Functional Artist]

Here is my version of a DIY chain drive steering rack

&
Here is a video of it...in action

 

[ezcome-ezgo]

Well have you seen one like this

Steering mechanisms should be as simple and as failsafe as possible. Belts and pulleys are probably not the best way to go.

 

[Hellion]

Well have you seen one like this

Wild. A belt driven steering assembly? What happens when the belt slips or gets wet? I won’t say it will break necessarily, as it is a low stress application.

What Ezcome said was what I expected to see. It’s still pretty cool. More photos please.

 

[70Cobra]

Well have you seen one like this

No I haven't...And for good reason. Replace the pulleys and belt with sprockets and chain if you want a solid steering solution.