Rear wheel camber curve question

SpeedRacer

Well-Known Member
How much camber change should I try for and why?

It’s a trailing arm (+10") race buggy with approx 20”+ of rear wheel travel. I have seen others set up at 0° to +1° at full droop (down), -2 ° at ride height and -6° at full bump (up). Does this sound right or is a flatter curve better? Why?
 

Mike_HKmtrsprts

Well-Known Member
I would contact Jerry Penhall on this he would be able to answer it no problem his number is 949-650-3035.....Mike

<font color=red>The dump you take is the gold I make so I can afford to play and race!</font color=red>
 

KitRacer

Well-Known Member
when i made my car, i put the trailing arm pivots on a 15 degree angle, it cam out to a preety nice curve. I didnt pull this out of nowhere either, i measured some of the other cars out there, the more degrees you put in at the pivots, the more camber change you get, and the more camber change you have, the more wheel travel you get. This is cause there is less CV angle when the camber is angled towards the transmission.

At baseball games they play organs, in motorsports they donate them.
 

michael_loomis

Well-Known Member
Eric your talkin about your prerunner im assuming ?

or did you cut off the pivots on the former "barney car"
 

KitRacer

Well-Known Member
yeah, the prerunner, not the "barney car". And its a total of 13 degrees. I put a 13 degree bend in the torsion housing, so that would mean 6.5 degrees per side right? All i know is that it cycled 25.5 inches of travel with 26.5 inch axles, but will be limited to 23.5 for ground clearence issues.

At baseball games they play organs, in motorsports they donate them.
 

FABRICATOR

Well-Known Member
You need to find out if you really have that much choice. Unless that thing is front wheel drive, or grossly under powered; at 20-plus inches of travel, you need to give the CV's and axles all the attention you can.

<font color=blue>"A Ship in the harbor is safe, but that's not what ships are built for"</font color=blue>
 

MNotary

Well-Known Member
We messed with that and picked up less than a 1/4in wheel travel. The CV would "bump/bind" when turned over at full droop. With the camber change it seems like it should be more, but that is all we got. At full bump the chassis is in the ground anyways.
 

KitRacer

Well-Known Member
thats interesting, i just learned of the whole camber curve thing, it sounds like a good theory. Oh yeah, and i meant 25.5 inches of travel limited to 23.5. If you only pick up a quarter inch of travel is it really owrth the angel (its way to late now anyways). i also heard that the camber change above center to bump is good for cornering, cause the tire is leaned in, anyone ever hear that or know if that really helps??

At baseball games they play organs, in motorsports they donate them.
 

MNotary

Well-Known Member
I should have added that the "bump/bind" of the CV at full droop did not change when the caster was changed. It is easy to check, just pull the pivot bolt. I think the spring plate bolts were loose... been awhile since we did it. You would think that because CV bind is at 30? somethin axle degrees, a extra couple of degrees of caster would give you that extra travel. Maybe on a long travel car it would make more of a difference. We did the check on a 1600 car.

Negative caster is preferred, keeps the contact patch flat. Like 2 degree spindles... Maybe not so important in the soft stuff.
 
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