Bent vs. Straight Drag link

It will have bump steer although minimal while going straight. I am also assuming that you somehow got all six pivot points (one side of the car) in line with each other. It probably wouldn't be enough that you would ever feel while driving but there will be some there. A lot of guys say that they have no bump steer and that's because they just don't feel it but there is still some there. The best you can do is minimize it or manage it but if you were to put a bump steer gauge on it you will find some. With the above description say you turn the wheel, now your pivot points are not inline anymore so you've just increased bump steer. We've also only described one side of the car what happens on one side also affects the other, not just bumps but body roll also affects bump steer. If you can't feel it then it's not a problem. On our dirt cars it's not so much of a problem, but on asphalt race cars tuning bump steer really improves lap times.

 

I wonder if you are confusing bumpsteer with rollsteer? Becuase I have been able to eliminate the toe in and out that occurs as the suspension runs through its travel, but I cannot even dream about eliminating rollsteer.

 

What the hell is that? lol It looks like a regular independent front with a cantilever coilover?

You haven't eliminated bump steer, you've minimized it. If you'd use an actual bump steer gauge you'd find it. What I'm saying is even if you almost eliminate it you will have it somewhere. Unhook your coils and measure it simulating different situations. turn the wheel and run the suspension through it's travel range you will find some bump steer. Simulate body roll then run one side through the suspension range and you will find some. Unless it's a rack mounted to an axle you cannot completely eliminate bump steer. The only reason this type has no bump steer is that the entire steering system actually travels with the axle. The only thing that has to move is that the steering shaft would have to slightly collapse and expand with suspension movement, but that wouldn't affect bump steer. If you wanted to take the time to over engineer a front suspension to have "NO" bump steer while going straight, you would have some during say body roll or turning, because pivot points are no longer in the same place. I never said that it couldn't be minimized it just can't be completely eliminated.

Ok for the sake of argument if really wanted to overdo something and designed some computer controlled actuators or hydraulics that lengthened or shortened radius rods/drag link/tie rods at the right times you could eliminate it, but with normal solid links it can't be completely eliminated. In my opinion on a street car as long as you don't notice it it's good enough.

 

Haha. Yeah, it is an A-arm cantilever set-up, only out of necessity though.

I understand what you are saying completely and I also agree that to eliminate ALL bumpsteer is impossible as well as neglegible. I have been called out on a few discrepencies and will be sure to be more specfic when posting tech advise.

 

Roll steer now I love roll steer!!!! It's my friend!

 

And don't forget, the rear axle can also steer the car in bends, as the body rolls, even if you have the 100% genuine 'no bump steer' front end filly scienced out, as the unequal length triangulated four bar moves the rear axle fore and aft on each side....

 

On my race car I have a three link swing arm rear suspension. The swing arms are short 14" arms. The rear arm angle really drives the left rear into the track, develops 4 to 6 inches of rear steer. I get on the gas six lengths before I did when I was running a mono leaf rear suspension.