steering, went in a new direction, thoughts...

Jump on the front - you'll probably get a good idea how much it works/travels.

 

4" vertical travel at the front equals 2" vertical travel at the half way point of the wishbone.


I wouldn't 'box' the wishbone.

If there's not too much of a conflict, it looks like the pitman shaft could be shortened a touch and a thinner nut could be used or cut the nut down thinner on a lathe.

Got room to space the steering box inward a bit?
If you're not going far, spacer bushings would work fine.

The car is looking good otherwise....

 

You drove it the way it was???
Then I'll bet you'll like the new layout...although it isn't perfect.
The Pitman arm shaft/wishbone arm interference scares the crap outta me though!!!!

You MUST get a fix going for that.

With the shorter pitman arm do you still get full turning radius from stop to stop?

 

yes i do, i will come up with something on that pitman arm shaft/wishbone thing i hope just want it safe for everyone around me, as well for myself

 

Ok this isn't by scale. It was the best that I could do with the MS paint. My new lap top has Vista, which won't recognize the drivers for any of my scanners or printers, so I can't scan any to scale hand drawings! Ok OT real quick.... Yeah Microcrap!! Anywho, back on subject.

You'll notice that with the angled drag link you'll see that through suspension travel the arc has a more for and aft direction compared to the hair pins more vertical movement. The farther the travel the more the geometry steers the car. On bump steer every arc effects every other arc. Graph paper is the best way to plot geometry because you can make an square equal an inch of travel.

 

i was fighting a low speed wobble after hitting small bumps in the road, iam hoping with this set up, at least i can drive it, more....

 

I just wanted to remind everybody that may not have seen my revision to the third drawing I did or just may not realize, as I hadn't, when I posted my original three examples, that you need to plot your arcs through the pivot points and ignore the radius rod angle. As they are the only relevant reference points in this particular type suspension. The axle, spindle and steering arm are all fixed to the radius rod acting as one single lever with the pivots at the rear of the radius rod and steering arm. The other part being the drag link, with it pivoting at the Pitman arm and steering arm.

As you can see with the radius rod and drag link parallel, there are opposing arcs.

http://books.google.com/books?id=b_...esult&ct=result&resnum=8#v=onepage&q=&f=false

 

Assuming the drag link is pivoting off a line drawn through the wishbone pivot point, will the length of the drag link have any bearing on things? I'm talking about a maximum 3" of vertical travel.

 

The more equal they are in length, the better and it is less and less an issue as travel diminishes.

 

Here is the closest estimation of the different set ups of this car I can come up with by looking at the pictures.


As it appears, the geometry is far better now. It could get even better if the box could be moved rearward more, making the drag link longer, and bringing it down slightly may help too.

 

How does the ratio of pitman arm to steering arm affect steering and/or bumpsteer? I believe the ratio should ideally be 1:1. My steering arm is 7" and my pitman arm is 4 1/2". Not a good ratio, but what will it do?

 

wow i cant be leave its took me this long to see what these drawing are showing me, iam seeing it now....

 

as looking from above, doese the the horizontal plane of the drag link to the steering arm have much effect, at an angle or closer to the radius rod...

 

Shouldn't be a problem.
Little easier steering perhaps, but the right size front tire and wheel with reasonable offset and reasonable inflation pressures will help.

My 32 roadster with BB Buick engine, T-400 trans has a Vega cross-steer setup.
The aftermarket flat ground 6" pitman arm has been heated and bent to 5" on center.
The car steers easy and the slower ratio gives you a mechanical advantage over a longer pitman.

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Reason I commented on wheel offset was:

A few years back I had a nice 63 Chevy half ton.

Got it from little brother and he had 8" wide wheels all the way around.
Done when the Can-Am look was popular.

The wheels were stockers, cut near the outside edge and a 2" band of metal welded in.
They ran true, but with a 2" offset to the outside, the pickup was hard to steer.

Much improved when I bought a new set of slot mags for it that had close to stock offset.

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Generally, bump steer will not be affected to any great degree with a pitman arm length change on a draglink (fore & aft) steering setup and not at all on a cross-steer setup.

 

Yep, as C9 said, not much as far as bump steer and different boxes have different ratios too, so sometimes it's just trial and error.

 

Looking from above, as far as the side to side angle of the drag link goes, it doesn't mean much. Unless maybe, it's excessive and your shackles are nearly straight up and down at ride height, allowing a lot of side to side movement. Then you could have a situation that might cause a wobble at speed (assuming you don't have a panhard bar).

Also, I screwed up a little on the last drawing by forgetting to include the previous steering arm height. I know this looks like a mess, but if you stare at it long enough, it will make sense. I doesn't make a whole lot of difference though and the new set up is still way better.


A1 & A2 are the old steering arm and drag link arcs, respectively. B1& B2 are the new arcs.

 

good to see craftsmanship....

 

one thing i will bring up, that iam sure makes a difference is that iam using a 3'' drop axle, so does everything still apply.

 

My guestimations are with whatever axle you have in the pictures and where the steering arm looks to be at ride height.

 

sorry i didnt think about that, you are right