What Degree of Chassis Rake, If Any?

I'm setting up my chassis for my 29 A this week and will be putting a kick in the rear. I am putting a new front crossmember in front and want to set it up with the proper degree. I've heard that between 6 and 9 degrees is ideal, and will be my goal. I'm setting my frame on the table today/tonight and wanted to set the frame as it would be desired to sit. I am up in the air as to whether I want a slight rake to the chassis or to sit level. This is my first hot rod, and have always had customs, therefore the inclination towards level.

Any pics or input would be greatly appreciated.

 

Hey Dirtbag,

Use 7 degrees in the front crossmember and I think most hot rods should have some rake, slight to mild, the rake can be handled by tire size alone,set the chassis up to sit level and use the tires to give you rake. Grey Baskerfield called it rubber rake.

See you next week at the GNRS! Bring beer!

Tex

 

But the "Rubber Rake" will decrease the front geometry rake, wouldn't it? If your right, I have been WAY overthinking this.

I don't travel without beer!

 

Set the rails up at ride height and set the desired caster into the crossmember. (5-7 degrees). A good source for this type of info is the Pete and Jake's catalog. Very good source of info on early Ford geometry.

 

4 1/2" ride height too low? That is where I plan, but want to keep it realistic. I am mounting my engine/trans so they do not hang below the frame.

 

Wow, thanks for this thread. Been working on first build and this has bothered me a lot. Got my Model A 28 axle dropped additional 3 inches and plan on 25" tall tires in front and 29" ones in back. Frame rake is about 5* now. Was going to set body back on and see how it looks this weekend. Wondered how much rake was enough? Maybe I am close now?

 

Yes, a rubber rake will decrease caster in the front axle, so you need at least 7 degrees at ride height and the tire size you are running. My roadster has 9 degrees at ride height. A little more caster is better tha not enough. Less than 7 degrees=DEATH WOBBLE!

You will need tires on the car to do this properly.

 

I'm not currently building a rod, but this is pretty interesting stuff. I have no clue how any of this is done. Can anyone show pictures of how Rake Angle is measured...

Sanchez, please post lots of pictures of your build, sounds like a pretty well thought out project.

Oh yeah, just to save someone a post, I am an idiot, but I can never overcome that handicap if I dont ask questions. They dont sell Rake Protractors at Autozone; they told me to check at Home Depot.

 

I've been using an angle protractor. It is magnetized and flat on the bottom, has a weighted pendulum pointer inside that will obviously point vertical, no matter what. It has a circle marked 0-90 every quarter, to let you know what degree your at, whether vertical or hoizontal, and a moveable red pointer that is able to be moved to a certain desired degree, on the outside. Believe it or not, I did pick mine up at Home Depot, in the tool section. I have an entire build thread on another site. I'm not sure how the mods are about posting links to other car building sites though. Here's a pic of a fellow club members truck that I am taking ideas from though. Mine will be more of a dirt track type than his.

 

This is a fellow Lifters c.c. member that I am building mine similar to. It's a four door sedan cut down to an X-tra cab truck. What do you guys think of the rake his is at, and should I go more/less?

 

its fairly simple to work out if you know your tyre sizes, and frame to axle clearances. a fairly standard chassis rake on a 32 frame is 3-5 degrees. so this number comes off the amount of caster you build into the front end, to give true caster when finished and running down the road.
if you dont have some idea of tyres and rake desired, you arent thinking far enough ahead in setting up your chassis.

working out chassis rake in the car posted above is near impossible, as the chassis has no base line, its bent like a freaking pretzel...

 

Wow. If you're trying to go that radical, then a lot of the "common" suggestions for ride height, rake, etc go right out the window.

Cool truck, but, the scrub line - eek

It looks like there is MAYBE, 2 inches clearance.

The bones have probably been cut to get the caster correct.

Huge kick in the frame, front and back.

If that's the look your going for, you best bet is to talk to the builder.

Rich

 

You need the tires you are going to run with first. Divide their diameters in half and that will give you your front and rear axle centerline. From that point on it's all about what you want and your taste in the rake.

 

Maybe. In California it depends on your side wall height. No part of the car can be lower than the lowest point on the wheel closest to the ground. Based on the picture, your fellow Lifters C.C. member's car is too low for the law, technically.

If there is 5" of rubber between the ground and the wheel lip, then you have to have the whole deal over 5" up.

You can visualize it this way: Put the car on the ground with wheels and no tires. Nothing but the wheels can be touching the ground.

Yes, these reg's were written before the days of low profile tires. I once measured a tire with 1-5/8" of side wall. So the car could have plausibly been 1-3/4" off the ground. But just try getting that past the cops, or out of the parking lot.

 

Thanks guys- the tire diameter's are 26" 5.00x16 Firsestone ribbed dirt track fronts and 31" 8.90x16 Firestone dirt track rears.

I hear what you guys are saying regarding the scrubline, etc., and is why I was asking what a respectable, yet good looking, height would be, and what degree of rake would look good or recommended.

 

Based on the tire, and assuming about 3/4" of wheel lip, you'd have about 4-1/4" to work with. I'd set it at 4-1/2" to 5-1/2". So long as you have a reasonable wheelbase, this should allow you in and out of most parking lots and driveways.

I find 3 degrees to be pleasing to the eye. It is just enough to make it look like it is moving forward, while standing still.

 

ditto on this.... set the wheels and tires and the front and rear axles in place , then build around that and the desired ride height. don't over complicate the process. its not that hard.

 

Don't let the chassis rake confuse front axle rake or castor. Say your chassis is raked forward at 3° and you need 7° axle castor, the front crossmember needs to set-up at 10° in relationship to the chassis. Also when positioning the crossmember allow for this 10° angle as it will move the axle centreline forward some. PS. these notes only apply if the chassis is set-up level on the jig, if it's raked on the jig it only the needs 7°.
Good luck.

 

Thanks guys- this was the info I was looking for.

 

31 Coupe is right. Your caster angle is measured in relation to the earth not the chassis. In other words if your running a 3* chassis angle and your chassis is sitting level in the jig you need to set your front corssmember in there and 10 degrees.

Frank

 

Here is the angle finder I was speaking of.

 

Yep, I'm no engineer but I think you need to have a set of painter's wheels or the rims and tires you want to run that are the exact size to start. Plan the chassis ride height and rake and then set the crossmembers. I doubt you can do very well without having the front and rear suspension / springs in hand, either. Then you need a mock-up motor to see if the pan clears the ground and the air cleaners clear the inside of the hood and that there is enough room between the firewall and the radiator for the engine and fan to fit. And then you have those dammed pedals, and then.... the knee bone is connected to the thigh bone. Get used to juggling at least 6 balls at once, too. And don't forget to feed the cat... and... and... and... Simple, eh? Gary

 

Looked online and did not find anything about this subject. Is the info in the printed catalog?

Thanks

 

i am new here, and new to fabbing a frame up, as i am about too do one for my fathers 29 5 window coupe. but as far as the rake goes, if i am building the frame, i only have too worry about this when i am welding the front spring perch on, am i correct? i am only asking because i plan on welding up the frame very soon, making it from 2x4x.120 square tube, 4 inch z in front, 7 inch z in rear.

 

Yes, but you will have to know what, if any chassis rake or rubber rake you want prior to welding. If your perch is a separate piece, you can wait until later, but if it is part of the front cross member, you will need to do it now.

 

I have to agree; it doesn't have "stance", it's just low for lows sake. Cars with fenders can look good super low, but that one doesn't do it for me either.

 

my perch will be separate as i am doing true suicide front end. thanks for the info, now i can start on the frame this weekend.

 

You are way over thinking it. You're not building a Datona car.

So-Cal Tex is right built it level and set up rubber rake after you're done. You won't build enough rake with the rubber to make any difference that you can feel in the seat of your pants. I guess if you put Mack truck wheels on the back ans shopping cart wheels on the front you could really screw it up.

I've always been a rodder and with few exceptions I have always built mine a little down in the snout. A mild rake is a sign of a true street brawler.

 

ok, i was thinkin about this some more. if i build the frame level, with my z's in it front and rear, why couldnt i weld in the front crossmember later with the correct rake degree. or as far as that goes, if my hairpins will have adjustable heim joints on the ends
, wouldnt that correct any caster issues too?.

 

Yes.