I have a 33 ford pickup with a pete and jakes four inch dropped axle with hairpins. How much castor do I need when the truck is finished, and how much is to much? Thanks Mark
How much you want/need depends on many variables, between 5 and 7 seems to be the standard. Do a search here on caster and read some threads then decide whats right for you. Whatever degree you decide on, the front cross member needs to be at the same angle.
Everyone will say 7 even not knowing what steering box ratio, or weight bias, tire type and size, and scrub radius(which includes wheel offset) that you have. in my opinion, which means nothing, I think all the above must figure into the settings.
Custom builds often require a small amount of trial and error. You want enough caster so the car tracks straight, but not so much that it becomes difficult to steer. Also depends if it is power or not. Too much is when you overpower the pump, start lifting an inside wheel or have the wheels flop over like an old harley chopper. As a starting point,not power, go to 2. Also be sure you have correct Ackerman or you will be scrubbing tires hard. Good luck.
7 degrees is a good starting point and usually ends up working fine. How much is too much? I guess the answer to that might be 10, although my 27 is right at about 10 and tracks and steers like it should. Don
7* is best but this needs to be with it on the ground at rid hidth. if not it will be all off with and rack or haow you have it sitting on jack stands. now to answaer your question on too much. 12* is to much. i have run 10* and it isnt bad but that is still to much for the street.
My axle is almost at 10*. Just how it landed when i mocked the wishbones up. I was told a spring behind axle would be fine to lay it back that much. I have no clue how it drives yet.
My 27 started out as 7 degrees but once the rear end settled down the first time I popped the clutch, it went to almost 10. I could adjust the radius rods to get less but it has been this way for 23 years, so I probably won't be changing it any time soon. It drives just fine as is. Don
Yep mine right now is at 10 deg, but that's with the frame at 4" off the ground. Air ride in the back, so the front end will roll up another 2 degrees probably when the rear is aired up for driving.
As just about everyone else above has said, you should shoot for 7* and then adjust from there. But for the record, a '33 is not a Model A. Just sayin'.
I would shoot for 7 But understand that having the ch***is at any rake will reduce the caster angle by the amount of rake say my ch***is is at a 1 degree of rake, and my caster is at 7..i really only have 6 degrees of caster another way of looking at this is have your ch***is flat and level , set up your caster at 7..raise the rear (ie rubber rake or suspension rake) and watch what happens to your set caster..it isnt 7 any more
Thanks again for the help, so 7 at ride height with the rake is where i'll start. I don't know much about what I'm doing here thats why I ask. As Cooter pointed out that a 33 ain't an a model, I didn't know that. I thought that they stopped at 34. All info is appreciated by this rookie. Thanks again
It will become obvious to you from reading various threads that sometimes there is no single right answer. We all base our opinions on what we have heard, or read, or what has worked for us in the past. That is why you will see such conflicting information sometimes, and why members sometimes get into heated debates. You will see someone say that "something won't work" and then you will see 10 other guys post that they have been doing it that way for 50 years with no problems. Don't believe everything you read in car magazines either as we have all seen articles with information that makes us go "WTF!" I guess that is why they say "Opinions are like belly ****ons, we all have them and they are all different." (or something to that effect ) Don
Not trying to hijack this thread here, but some of our readers may be wondering why this is important. You straight axle guys might insert some of the symptoms of wrong castor so the newbes can get a grasp of what to look for. As an example, when my car was set up as an altered, it had the typical spring behind T-bucket style front end. The original builder had installed a panhard bar, and a steering damper on the front end. I wasn't sure why he would do that unless he was getting a lot of shimmy. When I started the tear down to build a street car, I did some measuring, and found his castor at 2 deg! And, he had set toe out at 1/4"! No wonder the front end shimmied! Buggy sprung front ends are dumb simple, but they can be made to handle well if you pay attention to your measurements. As all the good advice before me, I wouldn't set castor until I had rake and ride height cast in stone. And remember, you have different toe-in, toe-out values for bias vs. radial tires. Hi-jack over, sorry, Mike
Good point Mike Britton, as you can see, by going through my username the truck I'm working on. It is nowhere as nice as the other builds on here. I'm just trying to throw it together to have one to drive. I really appreciate the help and any ideas and info, again being totally new to this the (why it needs to be this way) helps me a bunch. THanks Mark
The Jalopy Journal
