What's your SPRING RATE?

[crzycav86]

I wanna know the spring rates on your cars.

Lets start by having you list your spring rate, strut, and ride quality... I just wanna get an idea of what everyone is driving on...

Thanks..

[Q45tech]

Spring rates [manufacturers published data] are not the end of the story! Wheel rates of the spring is what one needs to know.Because a 1" movement of the wheel always has less movement on the spring.......thinking 93%of spring rate is a good approximation of the wheel rate. [on 240sx].

Newer cars like the G35/Q/M have springs attached inward of the knuckle [on a lower suspension arm] so the springs are stiffer because the geometry only moves them half to a quarter as much for every 1" of wheel movement.

Camber correction plates affect the wheel rates [differences in angles from the perpendicular].Wheel widths/offsets affect the wheel rate since the bottom spring attachment is offset from the center of the wheel by the knuckle.

[Ceptos]

i think what q is getting at is you should only be asking fellow 240 owners what their spring rates are =)

i have a small question for q45, are the spring rates and other things such as camber/toe directly comparable from an s13 to an s14?

IF SO, i drive a 95 240sx, my spring rates are 8/6kg. in my opinion, plenty soft for the street, i have a set of jic flt-a2's, and i could not be happier with the lump of cash missing from my wallet =) but its way too much for someone who is just casually improving handling, the money would be more well suited towards sway bars and other pieces.

[crzycav86]

Spring rates [manufacturers published data] are not the end of the story! Wheel rates of the spring is what one needs to know.Because a 1" movement of the wheel always has less movement on the spring.......thinking 93%of spring rate is a good approximation of the wheel rate. [on 240sx].

Newer cars like the G35/Q/M have springs attached inward of the knuckle [on a lower suspension arm] so the springs are stiffer because the geometry only moves them half to a quarter as much for every 1" of wheel movement.

Camber correction plates affect the wheel rates [differences in angles from the perpendicular].Wheel widths/offsets affect the wheel rate since the bottom spring attachment is offset from the center of the wheel by the knuckle.

I think I understand what you mean. Since the springs aren't 100% perpendicular to the road, it doesn't absorb the bumps as efficiently...... I think. In other words, it would take more torque(force[a bigger bump]) to make a spring that is angled at 45 degrees(theoretically) to bottom out than a spring thats perpendicular to the road. This is what you mean, right?

Although I didn't ask for that, its still good to know. So... whats your spring rate?

[Nismo_Freak]

6 / 5

Spring rate doesn't really have a large bearing on ride quality as much as dampening.

Think about it... you can push down on a spring and compress it quite far, quickly, but when you push down on a damper you need to exert much more force to compress it.

[Q45tech]

Actually you measure the free length vs the length with the cars weight on the spring to determine the natural frequency of the spring: Ideally the frequency should be 1.2 Hz for a lux car up to maybe 2 Hz."Spring rate doesn't really have a large bearing on ride quality as much as dampening".....but you have to damp a spring or the car will bounce off the road!

http://www.eibach.com/ERS_Worksheet.htm

http://www.smithees-racetech.c....htmlhttp://hometown.aol.com/EURORALLY/Suspension1.htmhttp://bsing.ing.unibs.it/~gad...1.htm

[Nismo_Freak]

Actually you measure the free length vs the length with the cars weight on the spring to determine the natural frequency of the spring: Ideally the frequency should be 1.2 Hz for a lux car up to maybe 2 Hz."Spring rate doesn't really have a large bearing on ride quality as much as dampening".....but you have to damp a spring or the car will bounce off the road!

http://www.eibach.com/ERS_Worksheet.htm

http://www.smithees-racetech.c....htmlhttp://hometown.aol.com/EURORALLY/Suspension1.htmhttp://bsing.ing.unibs.it/~gad...1.htm

I was more or less pointing out that in general the ride quality is affected moreso by the dampening rates and valving than the spring rates.

Case and point... Teins you can adjust them 3 clicks harder and it makes the same ride difference as 8 / 6 kgf/mm spring rates do. Not trying to disprove your scientific theory, but I'm going by my a$$

[Nismo_Freak]

Good reading BTW... I understand your point now.

[Q45tech]

They aren't scientific theories they a proven scientific LAWS!The science of springs has been well known and proven for 200 years.

But in a sense you are somewhat correct in that under damped springs may feel better [to some] in the car seat than correct damped or over damped. Depends on the velocity of the spring and the design/make of the seat, your weight in the seat............different humans respond differently to different frequencies of vibrations.

Time has lots to do with it [tolerance of vibration] how are the springs on an 8 hour drive on a bad expressway.

I get fooled all the time in my short 1 hour drives [with Eibachs and tokico blues stiff rear sway bar], then turn to jelly on my monthly 8 hour excursions.

[Nismo_Freak]

As you well know the rear sway bar your running will act like an increased spring rate in the rear. Not to mention the Tokico blues are nothing in terms of harsh dampening compaired to something like a 45 - 50mm Tein damper that's valved to be operated on a track.

I've ridden in a variety of different setups in the 240SXs so what I lack in scientific proof I make up with experience. There is a HUGE difference between a 5 / 4 kgf/mm RSR + AGX combo even set on it's hardest setting, and a Tein HA damper w/ the same rates on an S13. Fact of it is, the dampening force on the Tein is alot higher than the AGX is physically capable of. And thus the ride quality is worse because of the harsh dampening.

Spring rate plays a role, yes, as does sway bars (which as I understand directly affects lateral spring rates), I wasn't denying that at all.

I more or less stated that the dampening has moreso of an effect on the ride quality from what I've experienced.

[F4ucc]

Front 6.6 Kg/mm (times 59 for Lbs/Ft)Rear 5.5 Kg/mm With HTS shocks around, well not true coilover but they do a nice job.

later

[WongFeiHung]

What happened to the spring sticky with all the rates???

[Q45tech]

To answer an earlier question 90 Q45 [without active suspension have 123 lb/in rears [941 # AVG unsprung load] and 146 lb/in fronts [1080# static unsprung load] with full gas tank and a 170 pound driver.......nothing in trunk or glove box. There is a side to side load difference which I averaged. Obviously the left side weighs more than the right due to driver.

369 lb/in [6.6 kg/mm] vs 146 lb/in would change the front max body roll from 3.5" to 1.4" without any front sway bars, but the Q has a 29 mm front bar so the roll is limited to 2.8" roughly twice what the very stiff sprung 240sx might be???????????

The 240 sx has mcpearson struts [coil overs so there is no camber gain in suspension] vs the Q twisted angled upper link which provides enough gain to offset the tire going positive so the roll gets compensated for [if the tire sidewall is stiff enough to survive the loaded weight].

Loaded weight under cornering is pretty much the limiting factor and spring selection matters little as the weight shift is always the same - nearly. Actually body roll is the positive indication of the weight shift.

Too much stiffnesss reduces the warning time for drivers when the tires are about too lose it.

Impossible to make a 4300 pound car handle like a 3500 pound car no matter what tires, springs, sway bars you use.