Spring Rate Explanation

So the time has come for me to order coils for the y33. I keep reading about people switching their spring rates but I would like to know why? Can anyone explain the difference between them? 

Mine is a 2000 q45 with 272k (if that matters), no stretched tires (245/35-20) (proper wheels are next), and im favoring the tucked look over cambered. 

Tapa'Talkin on my Galaxy Note

:slap:

There goes Pat talkin sh*t lol. 

Im tryna stay smooth with my ride. Its a y33 it barely goes 0-60 lol. 

Tapa'Talkin on my Galaxy Note

just stay with 8/7 you nancy lol

I wanna set up for a future stance but still need to be able for the ladies to ride and tell me how smooth the ride is :D

Tapa'Talkin on my Galaxy Note

then get air. cant have the best of both worlds in this game

spring rate is the amount of weight (kg/lbs) it takes to compress the spring a certain distance (mm/in). hgh spring rates are used to limit suspension travel. the trade off is comfort and performance.

Ok my debate right now is 10/12 or 8/7. I think.. I want to retain the most comfort but i am looking at upgrading wheels in the winter

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[QUOTE=OG;454146]spring rate is the amount of weight (kg/lbs) it takes to compress the spring a certain distance (mm/in). hgh spring rates are used to limit suspension travel. the trade off is comfort and performance.[/QUOTE]
that makes sense, thanx for that detail. spring rates is something that i always wanted to figure out, i just didnt think it would be something this simple lol. 
 
[QUOTE=BossMaxima;454150]Ok my debate right now is [B]10/12[/B] or [B]8/7[/B]. I think.. I want to retain the most comfort but i am looking at upgrading wheels in the winter
 
Tapa'Talkin on my Galaxy Note[/QUOTE]
 
now on these 2 rates, why is it single and double digit? isnt 1 kg 2lbs roughly?

Depends on how low you'll be and how your wheel fitment is. If you have conservative fitment (not too low, wheels easily tucking under compression), which it sounds like you want, you'll probably be okay with the lower spring rates. People generally get higher spring rates to prevent too much compression under load to prevent rubbing, bottoming out, etc, especially when the car is extremely low.

Since I want the tucked look versus "stanced", I think I want to go with a softer setup. If I decide to get more aggressive later, I will look into Swift springs at that point.

I was going to place my order for the BCs today but now I have a misfire on cylinder 8. Went to autozone and bought a coil pack just to find out the problem is still there. Tomorrow morning Ill go get a spark plug to try and if it works Ill replace them all when I replace my rotors (whenever the company ships them).

Thanks for the help everyone, hopefully I get this all straightened out so I can get my coils!

[QUOTE=MaxiNone;454169]that makes sense, thanx for that detail. spring rates is something that i always wanted to figure out, i just didnt think it would be something this simple lol. 
 

 
now on these 2 rates, why is it single and double digit? isnt 1 kg 2lbs roughly?[/QUOTE]

I'm no expert on Spring rates and suspension parts, but 12/10 means 12kg/mm and 10kg/mm front. Which is stiffer than 8kg/mm front, 7kg/mm rear. But I'm sure you already got that. Anyways, If you convert kg/mm to lbs/in, you'll see that a difference in 2kg/mm is tremendous in lbs/in. 10kg/mm is equal to about 560lbs/in, while 12kg/mm is equal 672lbs/in. To your answer, yes 1kg is about 2lbs. But it's not just a mass issue, but also the height difference as 1inch is about 25.5mm.

Here's the math which shows how it's converted via. NASIOC forums:
(1kg/mm)*(25.4mm/1in)*(2.2lb/1kg) => 1 kg/mm = 55.88 lb/in
=)

[QUOTE=Ren335;454223]I'm no expert on Spring rates and suspension parts, but 12/10 means 12kg/mm and 10kg/mm front. Which is stiffer than 8kg/mm front, 7kg/mm rear. But I'm sure you already got that. Anyways, If you convert kg/mm to lbs/in, you'll see that a difference in 2kg/mm is tremendous in lbs/in. 10kg/mm is equal to about 560lbs/in, while 12kg/mm is equal 672lbs/in. To your answer, yes 1kg is about 2lbs. But it's not just a mass issue, but also the height difference as 1inch is about 25.5mm.

Here's the math which shows how it's converted via. NASIOC forums:
(1kg/mm)*(25.4mm/1in)*(2.2lb/1kg) => 1 kg/mm = 55.88 lb/in
=)[/QUOTE]
^ Point?

To the OP:
My 2 cents for choosing the right spring rate: for a heavily lowered (= tucked or "stanced if you may, doesn't really matter) I would always choose the stiffer option. The std. spring rate on an any given street coil-over is always on the soft side, track spec'd coils are different. 
Just an example from K-Sport's street spec line-up: Lexus IS (~3000lbs) std. SR is 12.0/7.2 kg/mm, MKIII Supra - ~3400lbs - 14.0/7.2 (soft as a mofo), LS400 - ~3800lbs - 18.6/9.8, GS300 - ~ 3600 lbs - 18.6/9.8.... so as these working as an example you can make some assumptions on the std. SR for different sized cars. 

For my Aristo (GS300 turbo) I would get something around 18-30 kg/mm springs. And currently it weighs about 3500 lbs, your Q weighs around 4000-4200lbs right? So does that make you want some bouncy ass little springs for a big ass car like you have...? :shrug:

Of course you can't compare Toyota's/Lexus' to Infinities because they have different suspension layout, too bad I don't know enough to take that into calculations as an correction factor on the Spring Rate/Vehicle Mass equation...

i've noticed a lot of people trying to go higher than they should for no reason. typical overkill mindset, but the reality is it's a tradeoff; meaning the higher you go, the more you lose in comfort and performance. precision is always the way to go. finding the lowest possible spring rate you can get away with should be the goal. i doubt there's many cats, if any, on this site who need more than a 20k, and most would be fine with <15k.

True true... and then there's the strut itself, how it's valved / external reservoir etc. etc...