Suspension guru's what we be the pitfalls of too much caster? I see 6 degrees seems to be the max, but what would happen at say 7 or 8 degrees?

 

I can't get mine over 4.8 for some reason. But I would assume too much would make the wheel hard to steer and you would lose road feel.

 

Well, the wheel would eventually hit the back of the fender well, since you obtain it by moving the top of the wheel's steering axis rearwards.

But before that, you'd have the problem of "too much" road feedback, especially on roads that aren't level. What caster does, is LIFT the weight of the car when the wheels are turned, thereby employing the car's weight to return the wheels to center; with too much of it, the car heads for the bottom of the ditch every time you let go of the wheel.

There's definitely a "sweet spot" for an optimum combination of road feel, straight-line tracking, handling, tire wear, noise, gas mileage, and so forth. "More" is not always "better".

 

I guess I was wondering if too much caster would make the car have oversteer?

 

No.

 

You should never ever ever have too much caster! You should always have just the right amount. Of anything.

 

My car has many alterations and at the moment the least amount of caster I can get is 6.5 degrees. It won't be to hard to get it back down in the 5s but I was curious if anyone has run more than 6 degrees? This car will be used mostly track and some street.

 

The least you can get is 6?! I haven't even heard of anybody being able to get 6.

 

Depends on the nature of the "alterations".

Anything that would produce THAT MUCH of a change, probably had other "side effects" as well.

 

I guess maybe a better question would be. Has anyone run a track car of any type with more than 6 degrees of caster and if so what does too much caster do? Good or bad.

 

Wow, I feel kinda dumb. I'm useing Founders caster camber plates and on the caster adjuster I had the four bolts in the outer holes. One set of bolts need to be in the center holes one set goes in the outer holes. By doing that I can easily get in the high 4s. But I still wonder what higher caster numbers would do. I know some of the C5 Vettes would go into the 9s. Just a thought.

 

Don't know if anyone cares. But have been doing alignment comparisons with other cars and I found that the new Camaro runs up to 8.5 degrees of caster. I find that interesting because the new Camaro is a strut car also.

 

If you move the struts too far back, the body of the strut will hit the strut tower at full compression. I have no idea how much caster that equates to.

 

A thousand years ago as a Ford mechanic in the 70's The mid 70's cougars and torinos had 7 degrees or more of caster. As Sofa said caster helps the wheel return to straight ahead position from a turn. These cars were extremely nose heavy with the engine hanging mostly in front of the spindle and a very long front overhang. The large amount of caster was needed to help bring the wheel back to center and to keep the nose heavy car from drifting at highway speeds.

Negative caster on a car has the same affect as a caster wheel with its pivot point (steering axis) ahead of the vertical center line of the wheel. With the axis in front of the wheel center line it direct or "pulls" the tire behind it. Think of pulling the handle on a child's wagon. Positive caster puts the top ball joint or strut pivot ahead of the wheel centerline so that the projected steering axis fall behind the wheel center line. This causes a very unsettling feeling as the car/steering wheel does not want to return to center or stay there when driving. Kind of like pushing the wagon backwards with the handle.

Your LS1 car has the engine set back and I think you posted a 52/48 weight split. You wouldn't need as much caster to return the wheel with this setup but the wide sticky tires may require more to get the "feel" right. All of the new muscle cars, Camaro, mustang and Challenger all have the engines far forward and large tires. They are also very heavy, usually over 4200 lbs. All of this would require more caster to get the wheel to return to center and give the car a sense forward direction.

 

I think there are several variables to how much caster you need. Weight bias, how wide of tires, but also I think kingpin angle or SAI as they now call it plays a part also. That's one of the things I've been trying to compare is the SAI of the strut cars compared to modern a-frame cars. Talking about lighter or more balanced cars needing less caster. The new Corvette is only about 100 pounds heaver than my car but with a perfect weight bias (with driver) They still run up to 8 degrees caster. I just need to get more seat time on my car and try some different settings, but my pos e-bay clutch has put a stop to that for the time being.

 

I run 5.5º caster with J&M products plates. I've tried two different camber and toe settings but kept the 5.5º caster setting. Seems to work well for my car.

 

How much camber could you get with the Founders plates?

 

About -3º. The master cylinder gets in the way in the drivers side.

IIRC, Founders, J&M products, and UMI strut mounts are all the same design. Spohns are different.

 

The side effect of excessive caster is supposed to be bump steer from what I've read. We know caster allows you to run less static camber because suspension compression with caster will increase camber. Like any alignment measurement, you can't effect one measurement without effecting the other, so as camber increases more dramatically during compression it will also change the toe, resulting in the steering wheel "jerking" over bumps. On my Malibu, I run about 1.75* caster because the track can get very rough, though I've been meaning to add more.