An out of the box initial look at a set of Zeta-ProR+ coilover suspension by MeisterR for my Evo X.
For more details visit www.meisterr.com
Many thanks to www.cyberspeeds.com for the quick delivery, support and answering lots of my questions!
----- ****Choosing the correct spring rate**** -----
Credit to GTWorx.com as posted on www.evolutionm.net
Usually when you see spring rates for a set of coilovers it's something like 8kg/6kg. Makes sense, since the EVO is a little front heavy right? Well actually there's another factor at play.
The EVO has a multi-link rear suspension. The rear EVO spring is mounted inwards on the arm just a little bit. Unlike the front strut which is pretty much mounted at the hub, a 5k spring rate in the rear does not mean a 5k rate at the wheel. Essentially the suspension arm is a moment arm....placing the spring inwards towards the pivot point means it needs to be stiffer. Sometimes you'll see people mention the "motion ratio." For the front EVO with the strut based suspennsion, it's close to 1 (almost). For the rear, it's somewhere between .6 to .9.
To get the "wheel" rate, you multiply the spring rate by the square of the motion ratio.
So that 8kg/6kg is really more like 8kg/3.7kg ish.
Can you make it work? Kinda. A lot of front camber and a rear swaybar help. But a lot of front camber reduces your contact patch in a straight line and a rear swaybar reduces suspension independence. And then there's the suspension frequency to look at too. So basically yes....you want a slightly stiffer rear spring than the front for the EVO 8 and 9.
The X's motion ratio's are more even, so if anything, spring rates should at least be matched front to rear.
Kevin MacLeod (incompetech.com)
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