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Author Topic:   Swingarm Zlink question
driver27
Member
posted April 22, 2002 10:04 AM
Depends upon the amount of anti-squat but jacking forces on accel typcally make rear spring changes to work backwards. So a softer lr spring would tighten both entry and exit in that case.
I have run upwards of 54% diagonal and 55% left on my z-link with no problems.
I would look at shock travel as an indicator to too soft of springs. Jammin has a handy calculator in the toolbox for calculating spring rates on swingarms.


WPP
Member
posted April 22, 2002 08:18 PM
WFO I AM GLAD YOU ANSWERED ON THE SWINGARM.Are you saying if the car lifts the springs work backwards I run a 325 lr and a 300 rr does this mean i can go to the 300 on the lr and still tighten the car up or maybe a little softer on the left rear I also like useing my pull bar to tighten the car by moving it too the left.


wfoondirt
Member
posted April 23, 2002 08:35 AM
wpp, you are correct, Although if a large percentage of anti-squat is present you probably won't notice a large difference on exit with a softer lr, but it all depends on suspention geometry.


WPP
Member
posted April 23, 2002 07:20 PM
Would running a softer left increase the lift on the left rear I believe it could help the car going in with the softer spring on the left rear .I BELIEVE the pull bar will keep the car tight coming off the corner running it toward the left LAST YEAR Inever could get the car to lift it stayed the same i also ran 18 degrees in my pullbar and i never really understood why the car would not lift this is a swingarm any comment on this would be good


wfoondirt
Member
posted April 24, 2002 09:02 AM
With the spring on the swingarm its not going to affect anti-squat (lift). You need to look to the linkages to change anti-squat. Is this on a z-link or a 3-link?


WPP
Member
posted April 24, 2002 09:50 AM
It is a swingarm with the springs mounted on the swingarm and the rear control arms running to the rear and they are adjustable were I can angle them straight or downhill I have always thought anti-squat come from the pullbar and also the foward bite . THANKS FOR THE HELP


wfoondirt
Member
posted April 24, 2002 12:47 PM
Anti-squat is defined in terms of percentage of weight reacted by the linkages vs springs. I know the fomula to calculate it but i don't have it infront of me so i don't want to give you bad information without double checking my memory.
You can visualize or sketch on paper and get an idea of the amount of anti-squat you will have by finding the ic and its relationship to an imaginary line from the contact patch of the tire to the cg. If the ic is above that line the car will lift under accel, and vice versa if it is below that line.
To find the ic on a watts link type suspension you have to extend the upper and lower links until they meet then draw a line from that point to the center of the axle, this gives you the side view swing arm (svsa). Then extend the svsa and the pull-bar until they meet, that point is the ic.

I hope you can follow that, its hard to explain without drawing it out. In a nut shell anti-squat is determined by the angles of all the links controling the rear axle and the amount of torque applied to the axle.



WPP
Member
posted April 24, 2002 02:38 PM
I have done a little research on the instant center and i done understand were the point cross between the upper and lower controlarms WHAT I have not figured out when you put alot angle in the upper control arms that moves the line up are you saying that were you mount the pull bar on tha chassis should be above the line the line when it cross between the upper and lower control arms.I will stop here were we will not get confused. LET ME KNOW YOUR THOUGHTS


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