Camber on rear a arms

[Stomper]

I am desingning my rear bearing carriers. I will be using a arms. Do I need to have camber or camber gain when my suspenssion cycles? If so what # should I aim for? Is it realy nessesary, and if so how do the buggys with trailing arms get camber change throughout suspenssion cycle.
Also, to determine ride height, is there a rule of thumb of where your ride height should be according to suspenssion travel. I realy hope this makes sence. :-\

[Engineer]

Camber change on the rear is strictly a matter of opinion as to whether it is necessary. IMO. 

Trailing arms would not have camber change, but most are semi-trailing arms similar to the original VW design.  The pivot points are not straight across the car, the inner pivots are slightly behind.  It helps with several things, reducing plunge giving camber gain under compression, etc.  However it also creates negative camber when drooped out etc.

Ride height is again an opinion and depends on how you want to use your ride.  Do you need more clearance for obstacles, or do you want to corner harder?  A general rule of thumb that I am going by is 30-40% drooped at ride height.  So if 12" of travel then it will be down 4" from full droop.

[Stomper]

Ok, for easy math, if I had 10" of travel, at ride height my suspension should have 6" to 7" of compression, upward movement, and 3"to4" expanssion (for lack of better word)downward movement

[Engineer]

Correct.

[fabr]

IMO most people do not design in camber gain because it will limit the available travel by adding additional static cv joint angle. If you want maximum suspension travel you will avoid camber gain.

[Stomper]

IMO most people do not design in camber gain because it will limit the available travel by adding additional static cv joint angle. If you want maximum suspension travel you will avoid camber gain.

So what you are saying masterfaber is build it with no camber or camber gain. That would be easy. with two exact same car, one built with camber and camber gain, and the other build with out, how would you notice it when driving them.
Can you have camber on a wheel with no camber gain through the suspension cycle?

Sorry for all the question, just trying to learn.

[fabr]

So what you are saying masterfaber is build it with no camber or camber gain. That would be easy. with two exact same car, one built with camber and camber gain, and the other build with out, how would you notice it when driving them.
Can you have camber on a wheel with no camber gain through the suspension cycle?

Sorry for all the question, just trying to learn.

Unless you have u joints or cv's that allow 25 or so degrees angle I'd build it with no camber. Same cars but one with  and one without will genarally not be noticable in the sand. On pavement there's a very noticable difference in cornering ability to have a progressive camber curve.  Yes you can have camber  and no camber gain.
 All above is just my opinion that is both shared and scorned . In other words ,ask 10 people and you'll get 11 answers. The real answer lies in the actual usage.

[Stomper]

Unless you have u joints or cv's that allow 25 or so degrees angle I'd build it with no camber. Same cars but one with  and one without will genarally not be noticable in the sand. On pavement there's a very noticable difference in cornering ability to have a progressive camber curve.  Yes you can have camber  and no camber gain.
 All above is just my opinion that is both shared and scorned . In other words ,ask 10 people and you'll get 11 answers. The real answer lies in the actual usage.

I here you on the 11 different opinions. I like to listen to all the opinions and make a decision from that. Then live and learn.  The car will be used on dirt/gravel roads,feilds and pastures. Keeping that in mind will I need camber gain?

I have type 4 cv so I only have 22 degrees angle.

[fabr]

I here you on the 11 different opinions. I like to listen to all the opinions and make a decision from that. Then live and learn.  The car will be used on dirt/gravel roads,feilds and pastures. Keeping that in mind will I need camber gain?

I have type 4 cv so I only have 22 degrees angle.

To me that says it all. No camber. You do not want to lose travel.

[Hammerworks]

I'd go with camber gain and the lower arm parallel to the ground with you in it ready to ride.

"The car will be used on dirt/gravel roads,feilds and pastures",How much travel do you really need to do this?I would rather have better handling.

Look at any redline revolt video then decide if you want camber gain.

[fabr]

I'd go with camber gain and the lower arm parallel to the ground with you in it ready to ride.

"The car will be used on dirt/gravel roads,feilds and pastures",How much travel do you really need to do this?I would rather have better handling.

Look at any redline revolt video then decide if you want camber gain.

I don't know about your pastures but ours............................ Seriously this is something that must be decided on an individual basis and there's really no "right" answer. Up to you now stomper.

[Engineer]

The whole point of camber gain is to try to keep the tire as close to vertical when you turn a corner and experience body roll.  When the body rolls over towards the outside of the turn the wheels lean with the body.  Because the weight is transferred to the outer wheel, the suspension is compressed.  If you have camber gain, when the suspension is compressed the tire starts to lean in at the top which is the opposite direction of the body roll so the camber gain brings the tire back closer to vertical.

Now on asphalt with a 10" wide tire where the face is basically flat, keeping the tire flat to the ground yields huge benefits.  Depending on the type of dirt tire you are going to run, if it is rounded from bead to bead and there is not a flat face on the tire, I don't see how the camber change would matter.  Many of the ATV style front tires have no flat face and the rears have minimal flat face.  IMO on dirt with ATV tires there will be minimal advantage to camber gain in the rear.

The other thing to consider is with longer travel it is very difficult to make the camber change useful.  If you have 10" of travel and ride height is at 6" and you set it up with zero camber at ride height and 6 degrees at full compression the question is how much camber gain are you seeing when you corner?  I would hope that the outer suspension doesn't completely bottom out when you corner hard.  If it did you would get the full 6 degrees, but I would suspect that under hard cornering you wouldn't see more than 2" of additional compression which would give you approximately 2 degrees of camber change.  On a short travel setup the change can be much more radical and useful because you don't have the extremes of the long travel.

Just my $.02

[Hammerworks]

I think theres more to it than just the tire being "square" to the ground.It also effects instant center,roll center,and mostly center of gravity.

[fabr]

Explain.

[sandracer1]

I want to touch on the revolt vid. I noticed when my brother drove mine that there does seem to be alot of lean on the back tires. And it is a little roll happy. I have lowered the ride height which helped. So my question is, is the rear suspension a design flaw or is it good for it to act the way it does. Seems F'ed up to me.