How long can the front wishbone be?

I'm talking un-split.



I'm wondering if I can avoid having a second center cross member by simply extending the bones. I picked up a set of 37-41 split bones, but they will still need to be extended a bit. You can kind of see in the photo were the stock Model A wishbone ends. The F1 crossmember is hanging down just a bit. That's where I'd like to put the mount. right in front of the rear wishbone mount.

Is it OK to extend the wishbone 11-12"? How will it effect the ride?

 

Not sure what you are asking?
We used a stock A wishbone, split it and mounted on our 32 frame. Dimensions worked out perfect.

 

Can I extend a stock wishbone 12"?

NOT split. Leaving it like stock.

 

Yes of course you can, the longer the wishbone, the better the ride. I just did what you want to do. I modified my A wishbone with sections from a 39 and it came out great, attaches to my f-1 crossmember in the same spot as yours.

This is how mine turned out, A wishbone ends and yoke with 39 wishbone arms.

 

Longer shouldn't be a problem. HRP

 

longer wishbone equals more better.

 

Thank you.

The cross member I started making really looked like ****. This will make things a lot cleaner, and a lot less work.

 

olskool34,

Have a picture of your mount from the front?
Really like what you did there.

 

olskool34 had this pic in his build. Exactly the problem I have.

 

Wisbone is the suspension locater and dictates the arc of movement when spring compresses...only consequence of lengthening would be to decrease the already small change in caster as axle goes upandown.

 

here ya go.

 

Yup, that's how I did the rear.

 

The wishbone determine the arc that the axle describes as it moves up and down with road bumps. The longer the wishbone, the more the axle moves in a straight up-down motion that does not try to twist the shackles and shocks, and the less the change in caster (re: Bruce). Those are both good effects.

However, the axle is also tied to the steering box, especially if you are using drag-link steering instead of cross-steering. If the bones and steering link are very different in length, you will end up with bump steer because the wishbone mount can't move, but the drag link can. You hit a bump, and as the axle compresses the spring, the wishbone dictates the travel of the axle. The drag link must follow that travel, and it will change its position relative to the axle by moving the Pittman arm if it must.

 

A stock `32 wishbone is already 8 1/2" longer than the Model "A"

 

longer will (virtually) never hurt anything. shorter absolutely will. the longer the wishbones, the less caster change will occur when the suspension goes up and down.

 

I will be running drag link and I reversed a Corvair box for steering. That was the next step, and a question for later on. I have been referring to this diagram for setting up the steering.

 

You are dead-on. Go for it!

 

Damn Beau, thank for posting that pict! I have been using that one for the last thirty years or so to explain bump steer and how to avoid it. I have always meant to scan and post it to my computer for use here but never seem to find time.

 

Don't shoot me, but sometimes there are good threads on O.T. forums. I found this while searching a couple weeks ago.

http://ratrodsrule.com/forum/showthread.php?t=3655

 

Why not cut them and take them to the sides?

 

I would like to add that the wishbone and drag link can be paralell and not have bump steer as long as they are the same length or as close as can be. If they are off abit most get by with no problems as the front travel is only 2 to 3 inches with most cars.

 

Porkchop- If it was on the ground I would. But I want to hide them, and be symmetrical with the rear. It's for looks more than anything. Plus, I have the parts to do it.

 

The steering on my avatar is exactly what you are building and I did it about 30 years ago. The car steered like a dream in fact I put a steering damper on it to give it some resistance. Jim.T.

 

And remember...we are dealing with short travel in the Ford front suspension, at the good point of the arcs shown.

 

Yeah, I hear you. They do look better tucked under when the body's is a little higher. Nice simple and clean work - looking good!