Cross steer or traditional?

Thanks for that info, I will mock things up today to see how many turns it will take for a 32 spindle arm length.

 

Dreddybear, can you remember how many turns this set-up was lock to lock? I want to be under 3, but need side steer.

 

Here is a photo of my steering set up. 30-31 Model A Roadster body on a 32 style frame. Steering box is off of a 68 Mustang. Less than 5 turns lock-to-lock, it gets a little busy in sharp turns. Turning radius is large. Otherwise, car steers well with no play or funny feelings going on. It also has a shock absorber on the tie rod. I like the look.

(o{}o)

 

It was about 3 maybe over. But i would need all of it just to turn the car. U turns were impossible. The whole thing was my bones weren't in a good spot to have the side steer come out of the frame. If I had mounted the bones inward on the frame I could have had less of and extreme bend on the pitman which would have let it be longer which would have been sooooo much nicer to drive.

My new setup it's like 1/4 turn of the wheel to make a 90deg right turn. Before it was like over a full turn..


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The car I'm working on needs the bones moved anyways, as the tires rub before full lock.

Trying to work with what parts he has already. I just wanted some idea if I could get down to maybe 4 turns with his stock 32 axle and spindles, steering arm. It's brave to just cut into a new boxed frame to make room for the F100 box, just to see if it can work....and then change plans.

He does have the aftermarket flange kit for the F100 box, but it's at his shop, not mine

 

I spent a few minutes with a static mock-up. Pics show:
-I moved the rear of the bones inboard for now, so I can steer all the way to both factory spindle/axle stops...to be able to measure what i need.

-Then ran a yardstick from C/L of the steering eyelet at driver spindle arm, and made a chalk mark 36" on the frame, when I went from full left to full right. I got 6-1/4" difference. (static)

-Then since we don't have a F100 pitman arm yet, I used masking tape with a centerline mark on big vicegrips at 6" from center of pitman shaft. Then ran the yardstick along the benchtop(creeper) to see how many turns of the F100 box would go 6-1/2" travel. I chose 1/4" more to allow for the factory freeplay in the box when it is not in the center. The box went exactly 3.5 turns to get 6.5", which was a surprise in a good way. I think we will go ahead with the F100 box install.


Ok, some boring stuff about "static" calculations. You might get full lock to lock with 6.5" at the box if the car was sitting on wet ice...no resistance to the tires and steering components.

We all know that these old steering arms are pretty slim and can flex, compared to a modern car. Add the old 7 to 8 caster, and they will flex more than when the caster is set at the lower factory specs of 4.5. (I'm talking the flex when parked on tar, not driving) Add in a dropped thinner axle like a 33-36, and the axle end will flex with side steer, more than say an undropped 32 heavy axle end. The dropped axle gives more leverage for flexing, because of the upper steering arm location for the drag link.

Add in the possibility of scrub radius being wrong, and you add more flex. add a heavier motor, more flex.

So, if you found some kind of side steer box with it's stock pitman arm that you refuse to cut, and if it's total stroke was only 6.5" lock to lock, that would not let this car hit the factory stops on tar, trying to park in a tight spot.

Note; this front end needs revamping. It is an undropped 32 heavy axle with 32 spindles and arms. Those ran the tie rod above the bones when new. But it has 35/36 bones which were for the rod to go under the bones. The arms for the tie rods were bent down to try to get the rod to fit, but it won't work too good that way.

Also, the caster is at 9 to 10 right now before the nose comes down, so it will be more caster. We will flip the bones, then piecut to 5 degree at what we think will be final ride height. Flipping 35/6 bones will drop it 1/2" due to that upper yoke boss being so fat, and reversing the spring eyes will get 1" more, and it also has too much spring, so we will pull some leaves and maybe all that will get it down enough.

We will also move the bones under the car even more. Bring that mounting bracket to the inboard edge of the boxed rails, then run the bungs reversed to have the nut facing the outside, rather than the grease fitting end. I think that may get the bone away from the f100 drag link.

 

have read suspension books...side steer is less prone to bumpsteer ...if using ford front suspension..id use dead perch...elimanates need of panhard bar...

 

more caster,,drive straighter...just harder to turn....

 

Im a fan of an F1 or Hudson box with the steering arm out the side, just looks the part for me, but in saying that I have built a few cars with cross steer, usually the 37 style Ford box but ive also used a mid 90's Suziki Jimny box, yea I know its Jap **** but the boxes are small and work great.

 

I note your drag-link is shorter than you 'bones

Which means when you left wheel goes over any reasonable bump the drag link will travel through a tighter up-and-down arc than the 'bone does.

Which may/may not cause some kind of bump-steer.

Just a thought.

 

Correct, but it's not my car.

Ford switched in 1935 to cross steer, and I would guess that was one reason they did.

Rodders have used this set-up on 32's since the 30s, and that is no excuse,.... but with the limited front suspension travel, it should be minimal.

 

Which may/may not cause some kind of bump-steer

You can get it to work fine IF you work to keep the same arc at the axle:

 

Thank you

 

Running a vega box, 4" drop axle, panhard bar and a GMC column. It steers easy, runs straight and has been no trouble.

 

update on the car on page 2.

It's done except waiting for new draglink parts from Spadaro, but this has a working link made from a 32-34 tie rod for mock up testing.

The steering works excl with full turns in both directions to hit each factory stop. Exactly 3.5 turns.

Did not modify the F100 pitman arm. The F100 box holes were drilled as close to the top of the rail as possible, to help with drag link angle.

Flipped the incorrect 35/36 split bones upside down and went with 5 degrees to match the front spring angle. Tucked the bones under the frame so they don't hit the pitman or the tires at full turns.

Undropped 32 axle with 32 spindles, with tie rod above the bones.