OK, I have been searching on how to set up the front suspension for the model a project I am working on. Was told to set the axle at around 8 degrees. Question is 8 degrees at what reference point on the frame. Having a hard time finding detailed instructions.... Any help will be appropriated... see pics below.. Thanks
When the chassis is at final ride height on level ground/concrete the axle should be at between 5-8 degrees.
The 7 or 8 degree reference is the caster angle on the axle - how much the king pin is laid back. So first set your frame with the rake stance you want, then set the axle caster. You can rough them both with your angle finder. Typical would be the frame about 3 degrees down in the front depending on your tire combo and look you want, and the lay the axle back 7-8 degrees. Check that with the angle finder set on the top of the kingpin hole. Adjust the rod ends on your radius rods and play with the radius rod rear mount bracket until it looks like you want and the angles work out.
8 degrees off vertical from the level horizontal of the ground Actually i run 10 degrees Posted using the Full Custom H.A.M.B. App!
How mad is your rake? How deep is your love? How much is a two bedroom house? What's 80 year old pvssy smell like? DEPENDS! Actually, I set rails up to an approximate ride height/angle right on my frame table. ('jig') Then calc the angle of crossmember to where the rails 'angle'. I use 7 degrees, as it can change either way one degree (tire/wheel combos) and I like a lot of caster.
The aftermarket front cross members are pressed to allow the spring angle to roughly run correctly! If you are installing your "Kit" my suggestion is to strip the spring to a main leaf only, turn your chassis upside down install the spring leaf into the front cross member, clamp it up and fit the remaining parts of your front ent! Have enough adjustment on the hairpin radius rods for micro adjustment! The reason for doing this upside down is that it orientates the suspension very closely to actual ride height and the brackets are easy to fit accurately and tach successfully! Sent from my iPhone using The H.A.M.B. mobile app
Less caster makes it easier to steer and more helps straight line stability at speed--that is why dragsters run more (as much as 35 or more degrees back in the day). Increasing caster increases trail (the amount that the tire contact patch is behind the steering axis) and thus stability is improved. Roo
As a follow up, my first post works well when you either have not yet welded the front x-member, or are using adjustable spring perch bolts. If your front x-member is already welded, and it's a typical aftermarket x-member, set your frame rake and check the caster. It's most likely in the 6-8 degree range. If you want more, you'll either have to take some rake out of your stance, or go with adjustable perch bolts to avoid spring bind in the frame pocket.
Was the frame manufactured? The cross member should have caster built-in. I know that it can get very confusing. Lots of info on the web read and study before you go crazy with the welder. You will get all kinds of different opinions about caster angle. 7deg seems to be the standard "starting point". Kinda depends on the stance of the car and the "rubber rake". As mentioned above. Basically caster keeps the vehicle tracking straight down the road also aids in the return-ability of the steering wheel coming out of a turn.
This guy has done this before! Follow his footsteps & procedure! Caster is the angle that mostly affects stability of the car and makes the steering wheel return to center (all other things being normal). Think shopping cart front wheel vs chopper. The shopping cart wheels shake like a dog shitting razor blades at walking speed & turns easy whereas a chopper rides straight so much that you can let go of the bars and still go straight yet doesn't handle worth a fiddler's fart in a wind storm. Now those are both extremes and don't weld 'er up with 60° caster in it, yet 10- 12° will work well for autobahn like speeds. Also look at your Ackerman angle and thrust angle of the rear end. Sent from my XT1585 using The H.A.M.B. mobile app
Answer- Caster is measured in relationship to level ground. Changing the rake of the car or ride height of the car will change caster. If your desired ride height is a 4* nose down rake, your crossmember fabrication angle relation between the frame and crossmember would be 4* greater than your desired caster. It take some accurate Kentucky windage to get this close. Being off a smidgeon doesn't make much difference as long as it's all headed into the right direction. In fabrication stage, changing the angle of the crossmember for caster will move the wheelbase too
Yes the frame is a manufactured frame Boling Brothers . I did some measuring and double checking last night and the frame caster is built in. Now the radius rods can be adjusted and set up to tack the brackets in place.
Makes no difference what the caster is...Angle of spring is immaterial but should be same/parallel to radius rod when loaded....
What in the world are you talking about . Caster maters if you want the car to handle well enough to stay on the road. The spring should follow the axles attitude (caster) any mismatch is taken up in the shackle bushings. They wear at a rate proportional to that mismatch. One could twist the spring anyway to make it fit, that fact doesn't make it right.
Interesting post.....has anyone tried making a tapered wedge to go between the top of the spring pack and the frame pocket to adjust camber. Seems a simple way to correct camber a few degrees if needed.
It's out there, a wedge that is. Could be used to correct build variations. But spring needs to be parallel with axle. Thats why it was suggested to remove all the leafs of the spring and just use the main spring for mock up. This way you can tack-up radius arms and load up the suspension to check travel. Also if you haven't done so, you'll need to plan for a track bar (panhard bar) with that setup.
The use of adjustable spring perches just about eliminates " spring bind" (and the resulting wear on the shackle bushings) I KNOW they are not traditional however they do work and let the spring "work" as designed. If you set up the frame as many have mentioned above then you will probably not have issues the adjustable perch just helps to refine the front end set up and ride quality. My 2 cents
A diagonal measurement is one way to check for square. There are others too. What exactly are you trying to check and I can get more specific on what to measure. The frame should be checked for square before measuring off the frame for axle squareness to the frame. If the fame is tapered or sort of curved and irregular it gets tricky.
I took measurements from the spindle hole to a fixed location on the frame. Did this on both sides of the front axle. it looks like its about 1/16 of an inch off on one side. This should not be a problem?? I also adjusted the radius rod on one side to locate the bracket that will be welded to the frame. When adjusted there is about 5/8" of thread engagement for the heim joint in the radius rod. Is this acceptable?? see pics
LOL what's 20 feet long and smells like piss. A rumba line at a nursing home. yea I know tasteless but what can I say?
I would shoot for more thread engagement than you have there. Rule of thumb: 1 1/2 times the diameter. I would then add a couple of threads more for adjustment. Just the way I would do it, others may disagree.
Exactly as above. Down here we are required to have a 1/16" hole in the radius rod to prove we have the required 1 1/2 time diameter engagement.
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