Technical Split wishbone - front end geomatry

I recently split the bones on my model A build and I'm looking for advice on mounting the rear pivot. Not visible in the photo below, but in the shown position the front axel is vertical an true. And you can see where the end of the wishbone is. Which is preferred, a tall mounting tab for the pivot, or reshaping the wishbone so the rear comes closer to the chassis? This will be. full-fender car.

Thanks!

 

As long as the font axle has( ideally) 7 deg of caster, measure at the top of the king pin the top should be leaning back, it doesn’t matter if the mounts are low or high as long as it’s strong.

With the fenders on you won’t see it either way, from here yours don’t look absurdly low or anything

 

Super helpful - thank you!

 

As long as they clear the fenders and aprons...........

 

I use tie rod ends with weld in bungs and the longer weld on bracket designed for model A's all from Roadster Supply.

 

Can I ask the reason for splitting them?

 

They would need to be heavily modified to clear the motor and reach the ball pivot.

 

Model A bones generally need to be pie cut, otherwise the rear mounts end up way too low. Clamp your spring down to ride height, set the axle to 7 degrees or so and see where the back ends up. Fenders or not too low rear hanger don't look right.

 

Good info, thanks. I should note this in not a A wishbone. Perhaps 34/35?!? It has spring hangers off the front.

That said, I hear where you’re coming from and will investigate!

QUOTE="RICH B, post: 14981794, member: 27669"]Model A bones generally need to be pie cut, otherwise the rear mounts end up way too low. Clamp your spring down to ride height, set the axle to 7 degrees or so and see where the back ends up. Fenders or not too low rear hanger don't look right.[/QUOTE]

 

[/QUOTE]
35+ bones. Look up Mike Bishop (AV8) on here. He did a tutorial on using a 33 34 wishbone modified with a model A ball yoke thing. I’ve done it many times and it works well.

 

It's a personal and visual choice to some extent. At the end of the day, you need the axle to lay back about 7 degrees. A few considerations. A longer wishbone frame bracket may torque the frame more than a shorter one. A wishbone that runs downhill excessively doesn't look good in my opinion. And in extream cases, you may get into scrub line issues. I prefer the wishbone to be roughly parallel to the frame rake. So in your case I would be looking to pie cut the bones.

 

Super helpful all!!
What are the pros/cons of splitting vs. original ball yoke? I know Tardel & Bishop are strongly in the ball yoke camp.

 

With a later wishbone, that ball will be way back. Will your engine and transmission setup clear ?

 

The only pro to a split wishbone is the fit around the engine and transmission. The pro to a stock wishbone is the perfect geometry with no bind or worry of twisting parts. It will also reduce the allowance of side sway which might affect your steering input.

 

Did not see if already mentioned ,7deg as it would set on ground ride height with Rake ,
I would recommend mock up with Rake ( if thats the goal) fenders , running boards on frame to get your look of location where to mount to your liking , then pie cut & angle bones ,

 

When changing caster at the bones, as others have said get the car at ride height and rake, check the caster, and then modify the bones. I cut from the bottom, leaving a little metal at the top, bend to suit and tack weld the bottom, and continue the building process. When you are totally satisfied, remove an do the final welding.

 

Great info all!!! I’m now leaning to retaining the wish bone style if I can. I’ll need to find a model A bone to modify within the longer arms.

this post had been very helpful, thank you!

 

You can sleeve in side stock bones then rap / & shape to outside diameter,
Just a Thought