Camber compensating suspension

[rdorman]

Reading Cobra magazine last night about the new offering from DAX and they showed and was talking about the new camber compensating suspension. Being a new one on me, I was hoping other had some experience/thought on the subject.

The suspension looked like a standard double wishbone set up EXCEPT the upper control arm inboard mount was mounted on a cam with a pushrod to the opposite side lower control arm. The setup was supposed to keep the tire 'perpendicular' to the road under the entire suspension travel and eleminate the need for a anti roll bar. Seems a little to good to be true.

Thanks
Rick

[RallySnake]

Rick,

Unequal A-arm suspensions were designed to keep the wheels vertical as the chassis rolls in turns. That's why they are used on virtually every true racecar in the world.

The last time I heard of a "camber compensating" suspension gimmick, it was a leaf sping for the Volkswagon beetle. The swing arm rear suspension was so bad it would jack up under simultaneous braking and turning and spin the car around (if you were lucky). The add-on leaf sping would keep the wheels from going to full droop and it really worked.

I am curious to know which suspension they are using that is so bad it needs help?

And just where did you find a Cobra magazine?

Paul

[rdorman]

Originally posted by RallySnake


Rick,

Unequal A-arm suspensions were designed to keep the wheels vertical as the chassis rolls in turns. That's why they are used on virtually every true racecar in the world.

And just where did you find a Cobra magazine?

Paul

Familiar with those, problem is, they have a lot of compromises and a limited usefull range. This sounded like something I would like to learn more about.

Cobra Magazine is in the UK. Good rag. I don't think they have much of a website but you can get a subscription by emailing kitcarman@ntlworld.com

Thanks
Rick

[flipper35]

I suppose the pushrod was supposed to operate the cam as the chassis rolls in the corner, or was it to minimize the roll? I don't see how it would eliminate an anti-roll bar otherwise as it wouldn't limit roll and weight transfer.

[strictlypersonl]

I haven't seen the magazine but I can imagine how the setup works (and I think it's a pretty cool solution, too)... I've got my own design, but it requires external power and control like some of the new active suspensions...

Compensating for roll 100% and allowing lots of roll (by eliminating anti-roll bars) may or may not be the best way to go. It's a good way to keep the wheels on the ground over bumpy roads, but sometimes the roll itself can be de-stabilizing. I think a combination of their roll-compensation plus keeping roll fairly low could work pretty well though.

"Unequal A-arm suspensions were designed to keep the wheels vertical as the chassis rolls in turns. That's why they are used on virtually every true racecar in the world. "

They are a major compromise. I doubt whether any modern racing suspension does more than a 30% compensation for body roll induced camber. There's a good reason for that: the suspension also has to absorb bumps, and such a short theoretical swing axle length will make for a very twitchy car because of moving roll centers. Really fast modern race cars are so stiffly sprung that there's virtually no roll and very little camber compensation - their roll centers are stable and very close to ground level.

[rdorman]

I find it interesting as well Bob. Going to have to play with the idea.

Here is a link to DAX

http://www.daxcars.co.uk/start.htm

Rick

[Mike Simard]

There's also an article in the latest Racecar Engineering about interesting suspensions. There was something about a suspension that had a roll center that never changes. It sounds great but everytime I try to read it, my daughter takes the magazine away from me and pretends to read it.