Technical Caster Question

Trying to understand Caster a little better. I have split wishbones on a 30 Model A. My question: What is my Caster? If I measure 10° at the king pins and my wishbones are 2 1/2° below horizontal at the back end, is my actual Caster 10° minus 2 1/2° for 7 1/2° or still 10°? This assumes that the floor is perfectly level (for simplicity).

TIA, Tony

 

10.

But when you measure it the frame has to be at the inclination the its going to ride at, often confusingly termed 'ride height'.

Chris

 

10* is a lot. I don’t have that much on my LSR roadster. It must go straight nice.

 

As HappyDaze mentioned, if you have your frame sitting on a level surface, and then when you mount tires and sit the whole thing on the ground.......if it is raked, that will offset some of the "caster" you built in. The frame needs to be sitting at the same angle it will when the car is done. Some aftermarket crossmembers are designed tp provide more caster (as well as slight lowering) and also angled to prevent spring bind as the spring moves .

Note: corrected the word "camber" to caster ..........had a brain fart there.
Thanks "@twenty8" for catching that.

 

Thanks Happydaze the car is done, this measurement is at ride height completely loaded (engine etc...)

 

I was trying to get to 7°. I can't raise the wish bones at the rear any higher to reduce the Caster. It drives pretty good so I think I'll just accept 10°.

 

I think I'd rather have too much than not enough. If it's at 10 and it drives good I'd be happy.

 

I put 10 in every Straight axle car I do as it makes it track perfect at eighty five going down the highway.

 

10* measured in my sedan, original wishbone.
7* in the other one, split wishbones
Both drive okay !

 

Good info, but you need to change the word "camber" to "caster" so people don't get mixed up.

 

Thanks for the info guys.

 

10* in a light car would be ok. Caster makes you actually lift the car's mass with the steering wheel as you turn left or right. The mass lowering itself is what gives the self- centering steering effect. If the car is heavier, a little less caster is a good idea.

 

Correction made and thank you for pointing out my mistake. I do strive to be accurate in what I post and appreciate when someone helps me correct some of the brain farts that happen.

 

I set axles on cars under 100" wheelbase closer to 10 degrees. But over 100", and especially more common around 112"-116" wheelbase, a 6-7 degree angle works just fine. I have 10 degrees in my 89" Austin, and 6 degrees in my '39 Chev coupe. Both drive equally well, but the Austin does not back up as easily with wheels cranked hard like the '39 does.

 

THERE IS ALSO ADJUSTABLE SPRING perches. Speedway #
910-33042 eliminates binding.

 

received my 6" lowered tube axle from Speedway a couple days ago. so yesterday i went to fit it to the springs to see how the width is going to work out, the spring pads DON'T work they are made for a rig with Stright frame rails and springs. the 31 Chevy has the frame and springs at a slight angle to the front. the pads fit the springs ok BUT the saddle for the axle is way off. looks like i'll have to make some, don't know what else to do.
Jay D.