For the hipermax III sport the spring rates are 11F 12R and standard hipermax III its 9F 10R.

Afaik almost all setups have higher spring rates in the front or at least the same. What could the reason be for hks using higher rear spring rates?

 

Oh man this is not going to be easy.

What to do based on based on so called dynamic laws of tuning/car setup.

What to do based on how certain elements of suspension design effect or alter the above (example anti dive and anti squat geometry and oem suspension bushing {deflection/compliance}).

What to do based on testing and wanting certain properties over others in spite of the two things mentioned above (example, at what point can you apply power as cornering loads begin to ease). And I will add in the possiblity that some may not watch or chase proper dampning control as this may effect their rate choices.

Look at say a 10 car field of 350Z's (Fairlady) campaining in what I guess are a few different spec races in Japan and look at their suspenison specs. You will not find common ground, some will be on front biased setups, some will be on equal bias setups and some will be on rear biased setups.

Remember, spring rates are one thing, what really matters is how much of the springs power actually makes it to the wheel, we call that number wheel rate.

Math example
616 X .688 X .688 = 292
672 X .649 X .649 = 283

Hks Hypermax III Sport
Spring rates 616/672 (wheel rates are 292/283)

Hks Hypermax III
Spring rates 504/504 (wheel rates are 239/212

2003/2004 oem 350Z
Spring rates314/342 (wheel rates are 149/144

2004.5/2007 oem 350Z
Spring rates 314/427 (wheel rates are 149/180)

Just for fun

Tein Mono Flex
784/784 (wheel rates are 371/330

Zeal XS with springs in oem locatoin
560/448 (wheel rates are 265/189

Zeal XS with springs on rear dampner (true coilover)
560/448 (wheel rates are 265/448 {because rear lower mount is attached diirectly to the wheel hub})

Stance GR+ with springs on rear dampner (true coilovers)
672/280 (wheel rates are 318/280

Stance GR+ with springs in oem location
672/616 (wheel rates are 318/259)

Stance GR+Pro springs in oem location
896/784 (wheel rates are 424/330

Ohlins PCV or DFV
560/392 (wheel rates are 265/165

TcKline DA shocks with Nismo T2 springs
Spring rates 690/690 (wheel rates are 327/291

Truechoice Phase III/IV coilovers
Spring rates 500/425 (wheel rates are 237/179

 

Wheel rate = wheel "spring" rate? Does this also take into account the rate of the tires you choose?

 

No. Without writting a book. Each given setup above shows you the spring rates. But, that doesn't show you how much of the springs power actually makes it to the wheel for perform work. Seeing the wheel rates, is seeing that number, how much of the springs power makes it to the wheel. Numbers shown are in the same format as the spring rates, lbs per inch.

I've never heard of tire choice being a factor in wheel rate.

 

i think those springrates might be wrong...

 

So let me get this right. Theoretically, two coilovers of different brands A and B. A has a spring rate of 12, and B has a spring rate of 10. A could still "feel" softer than B because it's wheel rate could be made lower than A?

So then buying a coilover for comfort, based on spring rates is going to be a bit of a cackhanded afair!

 

comparing 2 different coilovers based on spring rates has always been useless as **** on a bull.

 

Important to analyse the ratio between fore and aft springs to optimize the ride otherwise you get serious pitching and undulation on highway at different speeds based on wheelbase and chassis stiffness.

As springs get stiffer the amount of tire sidewall stiffness becomes less material.

 

I notice that the wheel rates rated on your setup are midfield in the 2-300s, while some are much higher.

wheel rates still don't tell you how much grip you have since it doesn't take into account rebound dampening over bumps, etc correct?

What are you trying to show with the wheel spring rates? what does it mean to me when I am shopping for a coilover setup.

thanks.

 

Yep, HKS lists the standard Hipermax III as 9f & 9r.

 

Everywhere i post you seem to be right there busting my a$$.
Granted you can't compare coilovers just on their spring rates, but at least you get an idea of how harsh the ride might be. So what i'm saying is that you can't even do that apparently. So the only way you can find the right setup is by trial and error, which is going to be expensive, or by taking someone elses word for it. And everybody knows that no 2 people are the same. So what might be comfortable for you, might be harsh for me, and viceversa. Know what i mean?

 

you need to find out alot of info that most coilover manufacturers don't release to really get an idea of what the coilover feels like.

 

clarifying a post is suddenly busting your ***? wow

thats just the thing...you really can't get any idea how the car will ride based on spring rates alone.

Yes I know exactly what you mean - everything in life is relative, from coilover comfort, to exhaust volume, to wheels being light, to tires being grippy, to a car being fast, to a restaurant having good food. That's why when you can't experience every option for yourself, you weigh the opinions of people smarter than you, or with more experience than you, and make your decisions based on that information.

 

Would the sports and the regular Hiperman IIIs have the same shock valving?

 

Rates are pulled from HKS Japan. It has not been HKS's practice to change the rates once the product makes it to our shores, LS LS+ and II have the same spring rates here and in Japan. The RS was never listed on the HKS site in Japan.

A much more troublesome issue needs to be resolved with the III. If for the first time from HKS, Z33 application's have moved to a truecoilover setup in the rear, either posted spring rate represents far too much rear spring power at the rear wheels. IMO, get your vendor of choice to verify where the rear springs mount before buying as in they open up the box and look. I've never been impressed with whoever picks up the phone at HKS, for everyone's sake I hope they are not a true coilover setup in the rear.

 

not sure where that rumor was started but its not a true coilover in the rear - it retains the same configuration as stock (ie the "right" way ), and has the spring separate from the damper

 

Gsedan, what about my question (that was for you) earlier in this post?

 

Your applying something in a way that you really should not. We are bringing up wheel rates for the soul purpose of showing how much spring is making it to the wheels. Yes the math will tell you things, but what it won't tell you is how well the dampners are controling said spring rate, that's something that is harder to quantify, but does seperate the men from the boys in the business so to speak.


For a comfort based coilover Tein has offered the CS for quite some time, that product and the Bilstein PSS9 would be hard to beat for someone looking for comfort. Not sure if the HKS III CLX represents a advance on comfort vs the LS, you gain full height adjustablity, but spring rates are higher.

 

Correct, dampning does matter. Compression and rebound dampning both matter, if for instance I want to up my front spring rates. Even though I have seperate rebound and compression dampning in the front, I will have to have the front's revalved to lower the compression dampning level and raise the rebound at the same time.

I wanted to show the oem wheel rate baseline so owners could refer to how their car is setup now and maybe consider where a given setup may take the car, especially setups with a very high bias in the rear. My own testing agree's the Unitech team that did the R&D for Truehoice, higher level's of rear spring rate compromises rear grip on corner exit. Though in the end, your supposed to be willing to run different rates to get the car setup how you like it rate wise, then fine tune at the limit behavior with adjustable sway bars.

 

Is the "sport" version also not a true coilover setup in the rear like the regular hipermaxIII version and the stock configuration which have the spring and damper seperate?