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Old 03-09-2009, 05:14 PM   #1
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Default caster vs kickup

Short story long...

over the weekend the track had a new layout and it had a big jump that i kept lawndarting the front side of the landing ramp until i got use to it. anyway the car seemed to get easer and easer to drive over the weekend. well after the race i noticed the the arms were bowing from the repeted hits and changing the kickup.

so my question is.

What does changing kickup do differatntly than changing caster in the hubs? Or are the the same?

I have adj front hingpin holders on my 808 and can easely get different degree c-hubs. so working with eather is no problem. i'm going to change the arms but would like to recreate the way the car felt.
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Old 03-09-2009, 05:55 PM   #2
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There are a few main things we use more kick up for.

One thing as you stated is to change caster, but not as much as we use it on rough tracks to allow the front to absorb the bumps.

Also more kick up will make your car jump higher. It allows the front springs a better angle to "push off" of the jump.

Another good (or bad) thing about kick up is that under braking it will transfer more weight to the front for better off power steering.


Hope that helps.
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Old 03-09-2009, 06:50 PM   #3
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The tweak in the arms that you mentioned will only alter the relative caster angle, not the Kickup... If the arms twist in any direction it will change the king pin angle but to change the kick up you have to alter the inner hinge pin angle in relation to the chassis.
So if you want to replicate the handling you found with the tweaked arms, i would suggest (assuming you have stock caster blocks) using 12° caster blocks to start with and see how it feels. You may want to also try the 14° blocks as well, however this may be too much?
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Old 03-09-2009, 08:22 PM   #4
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Kickup is like pro-squat for the front end. The more you reduce the angle of kickup the more the car will resist weight transfer to the front end. Also, the more you reduce the angle of kickup the more aggressive the car will become. If you were to angle the inner hinge pin so that it was higher toward the center of the chassis you would have the front ends counterpart to the rear ends anti-squat. This is called "anti-dive." Anti-dive is for on road only. When you increase kickup you increase caster (unless you change caster to compensate) When you increase caster you do nothing to the kickup. Think of what is happening with caster. Imagine if you were to lean the kingpins back all the way to where they are parallel with the chassis. Turn the wheel all the way and the tires simply lay over sideways. Your car will still go straight. Now tilt the kingpin forward to where it is 90 degrees to the chassis. Very little steering input and the car will turn a lot. This is the affect of caster at both ends of the spectrum, so you can see that a more vertical kingpin will make your car more aggressive off neutral, and vice-versa. In my opinion caster and kickup are two separate entities that perform two separate functions. I don't believe that kickup should be used for the purpose of increasing caster. Kickup has to do with the cars ability to absorb or resist compression from weight transfer, bumps, and jumps. Summary: reduced kickup may be run on smoother tracks to increase steering sensitivity and reduce weight transfer (dive). Increased kickup may be run on rougher tracks to absorb bumps and make the car more forgiving. Notice I'm using the word "may". As with every adjustment there is always a point of diminishing returns, and I really don't change my setup by much at all. Hope this helps.
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Old 03-11-2009, 04:41 PM   #5
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for the record, caster angle is measured from the ground, so kick-up is included in the total caster angle... also, they both help to smooth the high speed steering and priovide more on power steering and 180 degree turn power... less caster angle does the opposite... my .02
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