Model A Crossmember Degree??

What degree do I need to set my front crossmember in my model A.

 

6 degrees

 

I put mine in at 7, I'd rather have a little too much caster than not enough.
Good luck,

 

and I think that you should have the car at "ride height" before you do it.

ie get the rake in the ch***is, then set the angle of the cross..

good luck
sawzall

 

The angle needs to be measured when the frame is at the same angle as it will be at ride height.

Any leaf spring will twist a little,so as long as you are close,it will be ok.

 

Why is that?

 

Sounds like you're making progress.

Running bias plys? Get it to ride height and go with more degree in the crossmember than less.

I'll call you tomorrow night.

JH

 

I don't want to steal a thread but I was gonna ask this same question tonight...

If you're mounting the spring behind the axle to the wishbones, would you still try to set it at 7?

Do my thinking, since in that configuration, the caster is not dependant on the spring angle, you'd want it at zero at ride height. Is that right?

My crossmember is ready to be tacked in as well.

 

Caster is what makes the car track straight down the road. A little too much is no problem. Not enough and it requires constant steering input to keep it going straight. When a lot of rake is added you lose built in caster and can result in a squirrely driving car........especially in short wheelbase rods.

 

If your spring perches are welded to the bones, and perpendicular to the kingpin and the spring is mounted square to the frame and the frame is raked you would have negative caster............or a severely bound up spring. The spring mounting has to have the caster built in. On my AV8 roadster I had to pie cut the bones to bring the ends up near the frame to look right. Your shock mountings should also be on the same angle as the spring.
Good luck,

 

Funny thing, I just bought an A frame this weekend. The front crossmember is tacked in pretty sloppily. Judging by my eye, it seems like the crossmember is tilted back too far. I plan on removing it and reattaching it at the correct angle. This may sound like a stupid question, but what's the best way to determine your ride height when you have no crossmember, engine weight or suspension hooked up?

 

I had to modify the crossmember quite a bit to do it but mine's at 7 degrees now.

Thanks.

 

Caster is measured on the axle. If you have a spring behind the axle setup
your caster will be set by your batwings. The cross member for the spring
will not effect the caster, but make sure you have no spring bind.

 

here is how I am setting my ride height with the parts I have, I dont know if it is right. I plan on running 24" in front and 29" in back, so my spindles are jacked up to 12" off the ground (the axle and spring are attached to the front end) in the rear I have the rearend blocked up to where it would be with 29" tires, I dont have a rear spring in yet so I blocked 5" between the top of the axle tube and the bottom of the rear crossmember. This should approximate my ride height. This is based on something I read in a Tex Smith book, I cant vouch for it is right or not. If you know how to use an architects scale I think you could probably make a pretty good scaled drawing.

 

I was wondering the same thing

 

Thats not a stupid question at all!!! I've got an A crossmember tacked up at 5 degrees, in my '34 Ply rails. (rear boxed to the factory xmember, keeping the factory boxing in the front. How do you account for crossmember dregree with out any other accessories??? Springs mounted, engine/etc???

I've been following threads along these lines for a few weeks. There have been several good threads on determin ride height, However I dont have wheels, just the rear, front axle & Front crossmember....


Dont mean to sound strupid but its a learning process.

 

With my frame level my cross member is at 11 degrees.
At ride height I have 4 degrees of rake in the frame and the crossmember is at 7 degrees.
4 + 7 = 11
Gawd I hope I did that right.

 

Too much caster will make it excessively hard to turn the steering wheel, and it will "snap back" to its "straight" "central" position quickly both of which make steering your car awkward and uncomfortable.

 

The ckdesigns guy is the closest. Apx. 4 degrees (down in front measured @ firewall, & 7 d. of caster n ft. x member. I run 9 d. in one of my 32's, sure goes straight but turns a little strange g. luck jat

 

I'm guessing that since the OP asked the question 8 years ago, he probably got his answer. I bet his avatar is the car he was building when he asked the question.