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Author Topic:   Swing arm spring rate?
dawg9
Dirt Roller

Total posts: 12
posted April 10, 2005 08:06 PM  
What is a good spring rate to start at.On a DW8 with 4bar on LR spring behind.I was told 250 but that seems pretty light with a 12.5 inch swing arm.I know on my Rayburn with a 15.5 swingarm he starts at 400.Of course thats a late model.Just looking for a good starting point.

Dman
Dirt Freak

Total posts: 270
posted April 11, 2005 08:01 AM  
The difference is the swing arm mounting vs. the spring on the birdcage.Swing arm requires a stiffer spring rate because the spring is further forward toward the frame mount and on the control arm. This completely changes the leverage or motion ratio at the spring.Usually double the rate of birdcage mounting.Get a book and do a little reading.The more you know,The faster you go!

rpm20
Dirt Freak

Total posts: 338
posted April 14, 2005 05:09 AM  
herE Is the formula, then figure like a regular 4 link rate so if you raN A REGULAR 4 LINK AND WANTED LR 225 AND RR 250 THEN YOU NEED ABOUT LIKE MAYBE A LR 300 AND RR 325 MAYBE. FIGURE IT ABOUT CLOSE AND YOULL BE THERE.
THIS IS FROM THE SWINGARM WHEEL RATE CALCULATOR ON THE TOOLBOX FOR THIS SITE. GET THE INFO THEN GO THERE AND FIGURE THE RATES.


Weight at the wheel for a swing arm!

Enter the required information into the black boxes and click results!

Tips

This calculator tells you what the actual spring rate is on a swing arm setup at the wheel!

You will need these measurements:

A) Entire length of the swingarm(center from bolt hole to bolt hole).

B) Measurement on swing arm from chassis mount to spring(or eliminator mount) to center.

C) Actual spring rate you have on that swing arm.
(A) Length of Swing Arm:

(B) Measurement to Spring Location(from chassis) on Arm:

(C) Spring Rate:


Spring rate at the wheel: >>

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[This message has been edited by rpm20 (edited April 14, 2005).]

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