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Acceptable Positive Camber Gain

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Andy.R View Drop Down
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    Posted: Nov/17/2015 at 2:01am
So, recently we have been having some integration issues and I am having to redo some rear suspension geomtery. With that, came a few constraints by the frame team. I am running into the issue of having to much positive camber in a cornering situation . I am considering 7deg of body roll and cant seem to get the positive camber gain amount to decrease without sacrificing a ton of negative camber at full compression. It feels as if I have tried everything suggested by Milliken to Smith with having all kinds of lengths and angles to my control links, and to no avail. Just curious what you guys use as a max positive camber value. Kinda vague, but any suggestions? 



Edited by Andy.R - Nov/17/2015 at 2:48am
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collinskl1 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote collinskl1 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/17/2015 at 3:29am
I always kept two points in mind when designing my systems. 

In general:

- ATV tires aren't as sensitive to camber as road tires
- Handling effects at the extreme ends of suspension travel aren't as important as the range in which the vehicle operates for the majority of the time
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i6overboard View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote i6overboard Quote  Post ReplyReply Direct Link To This Post Posted: Nov/17/2015 at 11:09am
And this is why we moved to a de-dion rear suspension; id love to do a front but packaging is difficult and havent come up with a clean solution.. Camber for solid rears is always the same relative to the ground surface no matter what body roll angle, plus a slew of other advantages. 

 

I dont think there is any way around your problem besides making a very short instant center, thus big camber changes like you have come up with.. Otherwise independent suspensions require some anti-roll to keep the camber good if that’s what you’re after, but as Kyle said, Atv tires aren’t as sensitive anyway, without tire data it is reliant on driver feedback and I don’t think a comparison has ever been done whether camber has a significant effect or not.. So, if you have to run an independent suspension you'll be stuck with that dilemma, to worry about camber during roll or camber during pure bump..

 

The problem I see with independents is when you up roll stiffness you also stiffen up the twist mode, which is exactly what’s supposed to be so great about an independent, having a soft twist mode keeps all 4 tires on the ground.. You can get clever with shock placement on solid rears to get a soft roll and twist mode while still having a stiff bump mode but no one seems to like that advantage.. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote RLM Quote  Post ReplyReply Direct Link To This Post Posted: Nov/17/2015 at 3:59pm
Are you looking at the tire relative to the ground at 7 deg of roll, or tire relative to vehicle center line? inner tire or outer tire relative to center point of turn?

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Tony Rivera View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tony Rivera Quote  Post ReplyReply Direct Link To This Post Posted: Nov/17/2015 at 11:33pm
Originally posted by collinskl1 collinskl1 wrote:


In general:

- ATV tires aren't as sensitive to camber as road tires

Whenever I see this, I think of this

https://etd.auburn.edu/bitstream/handle/10415/1350/Krueger_Darrell_10.pdf?sequence=1&ts=1433451253239



Tony Rivera

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