Technical Hairpin vs. Wishbone. Caster Angle. Do I have correct ?

Little new to old school solid axle front suspension. I made a little visual on hairpin vs. wishbone.

Am I understanding this correctly ?

With Wishbone, the chassis mount vertical location is determined by axle and changing vertical mounting location will change caster. Correct ?
Therefore, once mounted the caster angle is fixed. Correct?
Change in spring height or axle height will change caster angle. Correct?

With hairpins, chassis mount location is flexible vertically because two axle mounts are adjustable without changing caster. Correct ?
Caster can be adjusted with two front axle mounts. Correct?

Thanks

 

The thing to remember is this: have the frame at the finished rake first, before setting anything.
Aim to get the caster right from the get go. Any later adjustment can put twist into the spring.

 

You are correct. But as X38 says, changing the way the car's rake sits will change the caster. The caster angle is between the axle and the ground. If you raise the rear of the frame up it will reduce the caster.

Many guys will use wishbones, and mount the rear of them at a pleasing spot on the frame. Then they will piecut the wishbone right behind the forged yoke to get the caster adjusted properly.

 

I am looking to order 5-12 frame for channeled 1932 to 1934 Ford pickups from Boling Brothers for my 38 fenderless truck. I kind of like wish bone but their standard pickup wishbone is shortened special (because body clearance) which adds cost and makes it unique. I prefer off the shelf parts for future replacement if I have any issues. What I do want them to do is to prep the frame so the so its bolt on for me and no drilling or welding.

 

@waid786 At first I thought I saw carbon fiber rocker covers on the engine in the above post, but at a closer look I see they are angled fins. Who makes those?

 

The whole damn truck will be custom built. If you like wishbones, don't worry about availability for replacing it when it gets wrecked. A new replacement can be custom built again.

 

I may get Riley Automotive truck frame that is made specifically made for 38 pickup which is wider than 34 pickup and uses standard wishbone and parallel leaf springs in the rear which will make installing my Explorer 8.8 a breeze.

 

First was Richies DragMaster / Richies Nostalgic parr’s and then Nick Arias bought Richies business. Rich was in Washington state where he had the business. Look up Arias.

 

The Riley Automotive guy (Eric?) was banned from this site before you joined the HAMB.

Not sure why....

 

Lots of great information. Castor is the relationship between the ground horizontally and kingpin vertical angle. 6 degrees is pretty much the magic number for me.

I built my coupe and set the castor angle but when I went to a bigger rear tire I had to yank the wishbones and re set the castor due to a nasty speed wobble I’d get at 65mph plus.

To much castor will wreck havoc on your alignment.


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