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Ran into an issue with steering linkage.

So I made a thing, by (roughly) TIG welding two or three things into one thing:



My thing allowed me to keep the headlight mounted on the steering arm, but gave an arm for the tie-rod from the steering rod to push & pull against to steer the vehicle.



The thing also made for a poor steering rod angle between pitman arm and steering arm.



Please ignore my wrong pitman arm and steering rod, I'm using what I've got for mock up to get a rough idea of layout.

The major problem, besides rod angle. When you take tie-rod contact location out of the spindle axis it makes for an uneven Left turning vs Right turning ratio. One direction will turn faster & further then the other direction. I knew it going into it, but didn't think it would be as drastic as it really was. So, not only would one direction turn faster then the other, the car will also steer itself on bumps with the rod angle.

Plan B) After a few days of thinking, I made the decision to take the headlights off the steering arms in the name of maintaining steering angles.

So I made another thing. It's big, it's goofy, it's over exaggerated and I kinda really dig it.











Again, please ignore the wrong pitman arm and steering rod, still all mock up for ideas.



I figure drill three tapered size holes up the back of the steering arm to make it match and blend in with the rest of the car.

You can see my ginormous steering arm corrects the steering rod angle. But it introduces another problem. Since the steering arm is fixed to the spindle and it's not a 4-link style front end. The steering arm pivots with the axle during suspension movement. With the tierod way out in no-mans land, a little axle movement is exaggerated way out at the tie-rod.

Now, with this set up I've already jumped up and down on the frame trying to get the suspension to really move, and honestly there is very little steering movement. So I'm gonna run it, and if it presents a problem I'll address it then.

Now to make headlight mounts off the frame.
 
Today's project: Adding some 'Speed Holes' to the home made steering arm.






Then clearancing the body for full pitman arm swing.





I can now grease the tie rod zerk from inside the car



Also experimenting with a set of small lights, can't say I'm sold on them 100%



 
bob w said:
Your roadster is simply way cool!
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Thank You!

MercuryMac said:
The steering arm is the cats meow!
It fits with the whole car and takes care of bump steer.
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I'm afraid bump steer will still be an issue due to the fact that it isn't a 4-link front end and the steering rod pivot from the pitman arm isn't relatively the same level as the front radius arm pivot point. The higher up the pitman arm (cowl steering) the worse bump steer gets.

earthman said:
I vote for the bigger lights. Adds to the antique look imho. Have you been out in the street with it yet?
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I fully agree, working on adapting those big lights now. The little lights are "cool" but just not the same vibe.
 
Mykk, please hear me out on a unique 'bump steer' theory. "Store bought' engineers have told you about bump steer, and they're mechanically correct. They have scared you and thousands like you.
I have an engineers way of thinking, too, but, I also have 65,000 hours driving 'draglink steering' vehicles, [big trucks and farm tractors] in rough country. I have noticed bump steer occasionally, but never was scared by it, never. So, I think 'bump steer' is a genuine phenomena, it's just a way smaller problem than everyone thinks.
Your car is perfectly acceptable to me, in fact, if they scare you enough that you won't drive it, I'll drive it for you.
 
MercuryMac said:
Mykk, please hear me out on a unique 'bump steer' theory. "Store bought' engineers have told you about bump steer, and they're mechanically correct. They have scared you and thousands like you.
I have an engineers way of thinking, too, but, I also have 65,000 hours driving 'draglink steering' vehicles, [big trucks and farm tractors] in rough country. I have noticed bump steer occasionally, but never was scared by it, never. So, I think 'bump steer' is a genuine phenomena, it's just a way smaller problem than everyone thinks.
Your car is perfectly acceptable to me, in fact, if they scare you enough that you won't drive it, I'll drive it for you.
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I'd say bump steer isn't a widespread problem because many people are concerned and aware of it. If you've ever driven a vehicle that changed lanes when you went over a train crossing at highway speeds, your opinion on whether or not it's a big problem may vary. :D
 
Good point Snopro, we have to be aware of the problem and do the best that we can to subdue it. That mindset has probably kept the 'bump steer' grief to a minimum.
My point was, that we shouldn't get 'out of control' paranoid about it. A lot of my observations come from hauling logs, 'off road' out of the foothills of the Rocky Mountains and hauling gravel in the same area on oilfield roads. Our 'offroad' log loads were double the weight that the truck and trailer were made for, and the centre of gravity was about 7' to 8' off the ground. If you add all of those negative attributes, [rough roads, too heavy loads, high centre of gravity, and draglink steering] to the steering, you feel that those two front tires have a lot of work to do.
And yet, I hardly ever noticed 'bump steer', partly due to good engineering, and partly due to it being a manageable phenomena.
 
MercuryMac said:
Good point Snopro, we have to be aware of the problem and do the best that we can to subdue it. That mindset has probably kept the 'bump steer' grief to a minimum.
My point was, that we shouldn't get 'out of control' paranoid about it. A lot of my observations come from hauling logs, 'off road' out of the foothills of the Rocky Mountains and hauling gravel in the same area on oilfield roads. Our 'offroad' log loads were double the weight that the truck and trailer were made for, and the centre of gravity was about 7' to 8' off the ground. If you add all of those negative attributes, [rough roads, too heavy loads, high centre of gravity, and draglink steering] to the steering, you feel that those two front tires have a lot of work to do.
And yet, I hardly ever noticed 'bump steer', partly due to good engineering, and partly due to it being a manageable phenomena.
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I'd say most of that is related to the design of the vehicle. When you're combining a mix of parts by someone who isn't skilled or completely knowledgeable in proper geometry, the chances of getting detrimental bump steer are a lot higher.
 

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