Front Suspension

[Alex Evonosky]

All Front suspension

[akeller]

Hello,
I'm designing a chassis for a slab side 289. It will resemble the Daytona Coupe design but will deviate from the original due to a fully independent suspension both front and rear. The car will weigh about 2,200 lbs.

Up front, I'd like to use a common, readily available spindle that will stand up to the abuse. The spindle would need to be compatable with a hub or rotor of about 12" (I want to use 15" FIA style wheels and the rotor/caliper must fit that wheel); the distance from the spindle/axle centerline to the lower ball joint should be around 3" or less; the distance to the upper ball joint should be around 5"; it should be front steer.

Is anyone using the Mustang II spindle? That looks like it might work.

Any help or ideas would be greatly appreciated.
Al Keller

[Alex Evonosky]

Al K
The MII spindles (uprights) are real close to what you are looking for. The measurements are from the center of the spindle: to the upper ball joint is about 5 1/2" and to the lower is about 3 1/2". I say about because mine are mounted and a little hard to get exact.
Not sure about all the other caliper and wheel measurements you are looking for.
There are a lot of smart guys on here and sure some of them will have more input.
If you placed a call to someone like Pole Position 888-303-8555 they can give you the exact measurements of the #9302 and 9303 MII spindles.

Thank you,

[Dominik]

good day,

now we split our topics in various sub-topics, but not those into more subs...;-)

that is why I write here:
while building your own front suspension you may want to think about camber curves and roll center for a moment.

new generation tires, generally, or low profiles may call for less camber change in roll to keep the tire better on the ground.

the original suspension could benefit from shorter upper front control arm (3/8" shorter?) and a longer chassis bracket.

I also heard that one could change the anti-dive angle from 8 deg to 6 deg.

In case you mount a lighter engine you may get a way with a lower roll center in the front...

and the steering rack?...
how come most production cars do not have the tie rod end in line with the upper and lower balljoint, which is recommended by my books?
or is that why street cars need to be different to racing cars when it comes to Ackermann steering?

dominik

[Johnson]

How do you know how much camber change in role you need with lower profile tires? Also what is anti dive angel?

[mamba]

www.baselinesuspensions.com/info/cg.htm follow it and you will be free

[Dominik]

Johnson,

I hope that more people join this discussion, otherwise I have to flip through all my books to give you definite answers.

best, if we get answers from someone who does this every day.

you want to have the outside wheel, the one which takes the most load in cornering, as upright as possible (perpendicular to the ground)

15" tires (60 series) have a much higher "fudge" factor that 17" (40 series), because the tire shoulder is much softer.

let's see :-)

dominik

[Johnson]

One engineer I found states -.5 degree dinamic camber in roll with respect to the road for maximum traction with low profiles, but 0 to -.3 for static camber is what I have seen on pasenger cars. I can set the car up for 0 to -.3 static, and -.5 in roll, how does this sound?

[strictlypersonl]

Originally Posted by Johnson

One engineer I found states -.5 degree dinamic camber in roll with respect to the road for maximum traction with low profiles, but 0 to -.3 for static camber is what I have seen on pasenger cars. I can set the car up for 0 to -.3 static, and -.5 in roll, how does this sound?

-.5 deg camber relative to the road may give you maximum adhesion, but there isn't a street car around that has nearly that much camber gain under roll. Because the real-world road surface isn't bump-free, that much camber change would make the car very unstable at the limit, and there'd be some pretty "interesting" gyroscopic forces on the steering under straight-line running. Also, the roll center would move around way too much unless the suspension arms pivoted practically at the car's centerline and very close to the ground.

Usually, cars are designed with theoretical swing-axle lengths from track x 1.3 to track x 2.5.

[Dominik]

lucky me that Stricly P joined in, otherwise I would have to re-read my books in my holiday next week :-)

I will in any case, soon thereafter. Always good to keep educated.
I am supposed to know more about that, but I just copy the original design!
(you know, I just work here ;-)

cheers,

dominik

[mickmate]

I looked at a Plymouth Prowler front suspension tonight. It looks like one of the closest uprights I've seen to the originals geometry. Anyone familiar with them?

[Bill E]

Al K I started off using the M2 spindle the draw backs became plan after we started tracking the cars. The outside bearing is to small and needs to be twice as big. And the angel of the arm makes the rack mounting a little low. A word to the wise from someone who has ben there. You can use all the info in the books from the best engineers on the planet, and your car may still not get around a corner to save its self. The trick is to build every thing adjustable, and spend some time at the track with a prow driver. After all the tweaks are done you can install tougher non adjustable parts. Remember the longer the arms the better. and make the rear end narrower than the front.

[mickmate]

Probably ought to put this under brakes but it's close to front suspension. Check out the rotor hats I just made. I like the Halibrand wheel style and carried it over to these.

[Bill E]

Cleen verry cleen!

[Dominik]

nice one,

just maks sure to use the correct bolts for the brake hat.
speak to TILTON.
or read about it in one of Carroll Smiths' books!

I also like our pedal box!

dominik

[mickmate]

Thanks guys. Yup that shear vs tensile strength thing again! I did notice the threaded portion of the pins is kinda short. I was wondering if I should counterbore the holes or if longer ones are available.

[mickmate]

I finally have a corner actually holding a wheel on and tacked in place! Check my gallery if you're interested.......

[Rick Parker]

Dominik speaks the truth! Brake hardware must be of the best materials available, grade 8 won't do, especially in THIS shear application, the nuts must be of the slotted mechanical locking type too.

[troll]

Are there any photos here of the origanal 289 slab side suspentions.I did see them once at Kirkhams.That was back when none knew of them.I have a good memory but its short.They even had all of that stuff online.

[Rick Parker]

http://www.csxinfo.net/web/modules/xcgal/

You should be able to see what you are looking for on this site.