suspension spindle drawings

[TheRodDoc]

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[anders nørgaard]

Hi Richard,

I just drew this up very fast and didn't do it very accurately... just to eplain the principles (sp?) Nothing is drawn to accurate proportions!
Pulling the top ball joint inwards will decide where the virtual line through the steering axis (King Pin Inclination) crosses the ground/road thus deciding if the "angle" is negative (good) or positive (bad)

I don't know if you call Steering Axis Inclination in the transversal direction Castor?... In Europe, Castor is Steering Axis Inclination in the longitudinal direction! Top pointing towards the rear is positive Castor

Quote:
Most cars are either like the first or second drawings. A 57 chevy in my shop is like the center drawing but even more. A mustang is more like the first drawing. I all depends on how close you can get the ball joint line to the center of the wheel. Also the height of the spindle compared to the lower ball joint.

This phenomenum (sp?) hadn't been considered untill late '60es. Actually Volswagen where the first to take this up on their model K70.
I do not not of ANY car that is not designed with negative "Lenkrollradius" SCRUB RADIUS nowadays!!!!!

http://www.metalmeet.com/photopost/data/3687/Lenkrollradius_Polo.jpg
You're right about getting the lower joint as close to the center of the wheel as possible! This will allow for a design with a smaller amount of KPI/SAI to be able to obtain negative Lenkrollradius (don't know the english word for this) scrub radius
Castor makes the car raise on one side and lower on the other side during steering. KPI/SAI raises the car on both sides. When "letting go" of the steering wheel causes the weight of the car to "selfalign" the front wheels to "straight ahead"again (static selfalignment)

As you can see in the pic above, the center of the wheel is inside the virtual extension of the steering axis and the wheel does roll backwards and outwards!

CAUTION:
Changing Camber, SAI, wheel diameter or "Felgeneinpresstiefe" (distance from the center of the rim to the mounting flange on the rim will affect this angle!

[anders nørgaard]

Hi Richard (and everybody else),

they are getting this effect by the rims, not the suspension.

Like heavy truck rims where the bolt center is outside of the rim. new cars also do this with the rims. Even in this last picture you put here the spindle will still swing to the front and back. but since the tire has been moved in with the rim that changes it. I think they have done this because they now make the steering arms and other parts a lot lighter then they used to and this puts less strain on them when brakeing. Think heavy trucks use it for the same reason. less stress on things when brakeing.

For our car we can't use rims like that. Spoke rims even make it harder. The reverse offset on our car would look bad. The way you had your first and second drawings on the other thread is how cars here have been built up till the mid or late 70's. Most handle well. Anyway for the fender clearance for our car I think we better plan on regular rims and haveing them move forward and back when turning the car.

The reason they are getting the effect by the rims on the "german" drawing from a self study program for a VW Polo '95 is, that this car can be purchased with different tire sizes. In Europe there is a law that says, that NO part of the wheel may be outside the body, when the vehicle is moving straight ahead. As you can see below, the same effect CAN be obtained by changing design of the suspension. Only difference on the 2 pics is the spindle. the "original" (right) has a 14 deg inclination (SAI) and the left one is 21 deg. I know that is exagerated, but it's just meant to show that it can be done with suspension too!

http://www.metalmeet.com/photopost/data/3687/Turning_obtained_by_Suspension.jpg
The reasons of the way they design truck rims the way they do, are several.
One reason is to get a big part of the load on the bigger inner bearing and take some of the load off of the spindle end! Another reason is just like I try to explain to get the negative "Lenkrollradius" (annoys me that I don't know the english word for it... could someone please help?) On a truck suspension you don't want a SAI/KPI to big as this will have to "lift" the truck chassis "off of the ground" and combined with th Castor this will put the spindles and bearings under a lot of unnecessary load.

In the drawing below I've tried to be a little bit more careful with the measurements. The SAI/KPI is 14 deg. The top view to the left is an exact copy of the vertical rear view to the right. The circle with the Lenkroll.... is the same. The big circle in the topview shows, where the wheel would be, if it turned around the center of the tire. The "turns" are drawn in 15 deg intervals. As you see, the small circles are right on top of each other. You can also see that the centar of the wheel moves backwards at turning. If the bottom center of the wheel moves backwards, then so does the top, the front and the rear of the tire, which means there'll be more space/room in front of the wheel.

http://www.metalmeet.com/photopost/data/3687/Turning_Backwards.jpg

We can make the outer wheel on a turn move even farther backwards by using 4-lenker (multi link suspension) On an Audi A4 and a Volkswagen Passat, the outer wheel actually moves 1-1/4" backwards, as the wheel is turned 20 deg in!! I'll find a drawing and upload it

Later guys!

[anders nørgaard]

Here's the pic of the Audi/Volkswagen Multi Link Frontsuspension.
What is happening in the lower pic is very hard to explain with just a pic! I had to make a simple scale model of this suspension to make it possible to the mechanics in DK to "see" it with their hands. I'll see if I can borough the model tomorrow, take some pics and explain what happens when the wheels are turned in or out. Basicly the design makes some movements that causes the angles to be uneven on the left and the right front wheels. This normally causes a car to drag either to the left or to the right. Different camber or castor L/R causes "drag". This is being taken advantage of in this design!! Making a turn causes the Castor angles L/R to be uneven and thus the "tourqearms" that influences the suspension. A longer tourqe arm is stronger than a short one. This makes the wheels try to go straight ( the length of the arms gets even and the tourqes on L and R gets even/eliminates each other and the car goes straight forward. Doesn't matter if the car is accelerating or decelerating.

http://www.metalmeet.com/photopost/data/3687/Multi_Link_Suspension.jpg

[anders nørgaard]

Hi Richard,

good explanation. I got it. but, as far as the car we are working on, We have to use old style wheels. Don't we?

Meaning we can't use reversed centers on the wheels. I don't have a real set of spoked rims to measure but I would think that the back of the bolting surface must be toward inside of the rim. Im sure we could use reversed center rims but I sure wouldn't think it would look good at all on our car.

Thanks! I think you're right about using old style wheels. Looks far better on this design!

If the spoked rims have "loose" spokes, we might be able to offset the center in the right direction by using spokes of different length for the inside spokes and the outside ones. By doing so, we can "spoke up" the wheel like an umbrello (sp? "screen" to hold above your head when it's raining <grin>) Short spokes on the inside and long spokes on the outside of the wheel.
Just whipped up a quick drawing to explain <grin>


http://www.metalmeet.com/photopost/data/3687/Paraply.jpg

[bobadame]

Anders,

I think Lenkrollradius= camber. I think that scrub radius is a term that describes the distance from the center of the tire to the center of the "hinge" that it pivots on whether it's ball joints or a king pin.

[anders nørgaard]

Hi bobadame,

Anders,

I think Lenkrollradius= camber. I think that scrub radius is a term that describes the distance from the center of the tire to the center of the "hinge" that it pivots on whether it's ball joints or a king pin.

THANKS!!! It IS scrub radius... (makes sense) Using a design with a scrub radius different from zero, the wheel rolls instead of "twists" on the surface!

CAMBER = the wheel inclination inwards or outwards in top of the wheel! IN is negative camber and OUT is positive. CAMBER puts load on the steering arms and -joints, because a wheel that is leaning out in the top is trying to "run away" from the body and a wheel that leans inwards is trying to "run in under" the body. When they are the same, L and R, they eliminate each other and the car runs straight forward. If they are not the same, the car will run towards the side, where the Camber angle is "most" positive (can be negative! - 10 minutes is more positive than - 20 minutes! <lol>) Another reason for the value of Camber than "pretension" is tire wear. A car that has Toe-In wears the tires on the outside shoulders. Designing the suspension with negative camber, that wears the tires on the inside shoulders distributes the wear to both sides (and the center)

Thanks again!

[astroracer]

I am able to design a complete suspension if that is necessary. I do this kind of work at the "day job".
I can design and optimize the suspension if you can give me the basic parameters and I can do it with off the shelf, cheaply obtained components. I can also run articulation studies to check clearances to other components.
Check out the front suspension components I have drawn up for my Bad Ast project. Off the shelf Astro Van 2" dropped spindle with fabricated control arms and coil over shocks. Cutting the brake rotor off an "F" or "G" body disc brake leaves the hat/bearing asm and allows me to run Corvette brake rotors and calipers.
http://www.clubhotrod.com/photopost/data/500/7418au04_strg-rack-btm-iso-med.jpg
Let me know if I can be of service...
Mark

[Wray Schelin]

Hi Mark,

Are you kidding us? <grin> Of course we need your help!!!

Hopefully some other members will jump in and help as well.

Richard is doing the heavy lifting right now figuring out the surface development of the body shape and what works best spacially. Oscar has made it possible for all the CAD guys to get to work with his essential 2d drawings. Behind the scenes John, Mike, and J are working on or preparing to start drawings that will be refined to a working standard from which we can fine tune all spacial details.

We will need suspension specialists and frame specialists very soon.

If anyone has skills in those areas now is the time to jump in.

Thanks

[anders nørgaard]

Hi Mark,

Great graphics!
Could you supply a top view, clear front and side view?
Some specs would be nice too! Castor, SAI, Camber, Rim size (diameter, width, off center) tire size, Toe-in/out, Toe-out-on-turns.
Thanks!

[astroracer]

Anders,
I can supply all of the above.
I have suspension design programs that will give us any numbers you desire. What you see in the previous pic is a suspension design that I have optimized for my Astro Van. What I require for the Sultanofspeed is the desired design parameters. We can get more in-depth of course but, initially, I would need target numbers for:
* Track width
* Rim/tire sizes
If we can agree on these parameters I can start plugging points into my programs to get some baseline numbers. I can then optimize all of the conditions as we see fit to construct a viable/buildable suspension.
Mark

[anders nørgaard]

Hi Mark,

Thanks!
Then we just need to decide if 105" wheelbase and 61" track is OK and someone to decide on the wheels.
I think this suspension topic is very interesting. Don't have any CAD software for this (either), but I do have the Allan Staniforth book on suspensions construction and I do know how to use the "string" method of finding pivot points for a design that will work <grin>

Funny... not very many know that when "measuring" Castor using a wheel aligment tool/computer, you're not measuring Castor, but a change of Camber during a turn in and out 20 deg (4o deg)

[astroracer]

Another way to look at this chassis concept would be to utilize a current chassis. An S10 pickup chassis would be a cheap way to go. These things are a dime a dozen in a bone yard and the aftermarket support is phenominal. Full air suspension is a bolt on deal and replacing the rails to make them work within the scope of the project is a simple matter also. 2x3x1/8th wall tubing would plenty stout with a good crossmember design and possibly an integral roll cage incorporated into the body structure. Lots of things to think about.
Mark

[Boogiemanz1]

Mark if you read back throught he Bugatti Build posts you will see that using an existing frame has been thoughly evaluated and rejected. Building a custom frame is pretty much set in stone at this point............john

[bear193442]

Members I contacted Dayton wire wheels about 20" wire wheels in there line i think by the time the cad guys are finished or far enough along that ill have info back from them and ill post it here for everyone to mull over.On there site I found a pic that may interest you as it did me .I tried to post pic but got a menue that said it was to big. Bear

[astroracer]

From my previous post...
"replacing the rails to make them work within the scope of the project is a simple matter also"

Utilizing the complete frame would be a problem yes, but, using the front clip is still an option and would get you a well designed front suspension equipped with disc brakes and off the shelf repair items... This is the direction I would take as the engineering work is already done and we wouldn't be re-inventing the wheel so to speak. Anything would be possible here. 2nd Gen F-bodies have a lot of aftermarket support as do late 80's to mid 90's Pick ups and both of those would be pretty close to the target track width. Of course the track width can be adjusted with rim offsets so nothing needs to be exact dead-on to target....
Mark

[seasalt]

So far the front suspension seems to be nailed down to A-arms, but I was wondering, is the rear suspension going to be live axle, or independent?

Corvette, Jaguar, or fabricated?

There has been a lot of talk about Corvette mechanicals, but a recognition that the current Corvette chassis wouldn't be adaptable. That doesn't mean a rear suspension assembly couldn't be adapted though, and with an independent rear the tailshaft part of the transmission tunnel can be smaller.

The best match to plan size was 245's on 22" rims? If you downsize tyres it could negatively affect the look you're after. Trying different sizes on the drawings will show any negative effect. If style is king, then the large diameter wheels look more correct for the period....

[tbody321]

These rear ends can be bought cheap at Carlisle swap meets. You also could take a look at what Progressive Automotive.com is doing with corvette rears.

[FriarTuck]

Hi Guys,
The 95 T-bird has a great modular IRS that might work, and it is really cheap. I've seen new ones complete hub-to-hub on E-bay for $500.

[ham]

I am also in the process of designing a front susp for a 1933 chevy. I origanally thried to use corvette spindles but came up with a roll center out of this world. My next step is to find a spindle with a lower ride height.A stock pinto susp. has a roll center of about -2.5 inches whitch is too low to acheive proper handling. I know i can change my roll center with my upper control arm, but on this car with the front fenders the way they are mounted i can't relocate. I need to start with a spindle that has the snout raised up.Can anyone help me? a stock pinto spindle has a height of 2.4375 from cener of snout to bottom of spindle amd a chevelle is 2.5.

[anders nørgaard]

Hey ham, (insert real name, please)

What's the "snout?" :o

[ham]

my real name is jerry hamby. i am calling the snout the taper pin the rotor slides on.

[anders nørgaard]

Hi Jerry,

Thanks for explaining http://www.metalmeet.com/forum/images/icons/icon7.gif

Do you have any pics of your project? We LOVE pics :lol:

[ham]

dont have any pics at the moment still in planing stage.

[astroracer]

I need to start with a spindle that has the snout raised up.Can anyone help me? a stock pinto spindle has a height of 2.4375 from cener of snout to bottom of spindle amd a chevelle is 2.5.
Hey Jerry,
You need a dropped spindle. 2" is common and you can get them for the MII, S10, Chevelle, Astro, And a ton of others. They are common and can be had for cheap on eBay.
Mark

[Stormstyles]

Hi Guys,
The 95 T-bird has a great modular IRS that might work, and it is really cheap. I've seen new ones complete hub-to-hub on E-bay for $500.
I bought mine from a local yard for 100.00 then upgraded it for another hundred to a 8.8 with limitd slip and new case.

[Stormstyles]

Hey Jerry,
You need a dropped spindle. 2" is common and you can get them for the MII, S10, Chevelle, Astro, And a ton of others. They are common and can be had for cheap on eBay.
Mark
Hey jerry Check this site out and you will find a host of spindles there that might just help you out. http://www.finalfab.com Hopefully this isnt against the rules. :shock: :lol: