Suspension Rant

[SySt]

I have been wondering why all the springs for our cars provide a MUCH stiffer front spring than a rear. True, a softer rear promotes traction better while launching. I do feel the front should be stiffer than the rear on most cars. A stiff front end seems to promote understeer.

My roommate is big into drifting. Some of his friends are sponsored and they are all good drivers. Why this is significant is that he has ALWAYS liked a stiff rearend to break the car loose and he rarely uses "power over" techniques, he generally uses weight transfer and brake power to break a car loose. Also, a LOT of springs available for the usual drift cars have a stiff rear, even though the front is still stiffer, the ratio is far less.

 

[mrnickleye]

The 'normal' spring setup is what you've stated. Stiffer front due to the weight of the front end, with the engine. Normally, hitting dips and bumps, the weight that is 'plunged' into the dip would allow the car to bottom out more often with softer springs.

The springs are what hold the car up. A softer spring in front would allow the car to sag (be lower) due to the weight.

 

[SySt]

True, but I mean taking the eibach springs and keeping the front just as stiff, but making the rear stiffer. You know what I mean?

 

[IJ.]

Won't be much fun to drive when the tanks low on fuel Syst.

My Datto had a 120L tank (31 gallons) and the springs I used were stiff enough to give me the correct ride height but when the tank ran low it was too stiff/harsh and it killed the brake balance!

I got around the balance thing by using a load sensing proportioning valve from a light commercial vehicle.

 

[cjsupra90]

yeah, braking is one of the main reasons as to why the front is stiffer. There is no perfect setup, everything is a compromise. what might be good for one condition might hurt you in another condition. you also pretty much have to increase the spring rate if you are lowering it inorder to keep the car from bottoming out. the hole point is, nomatter what you are using the car for, you have to find the perfect balance in all condition that the car might experiance and therefor making the selection of equipment to try to achieve that balance.

 

[SySt]

Wait, now tell me how stiffening up the rear would change braking. In a turn sure I can see it, but straight line? I do not get it.

 

[Mr.PFloyd]

Wait, now tell me how stiffening up the rear would change braking. In a turn sure I can see it, but straight line? I do not get it.

it will make the car more stable because the back wouldn't lift up as much causeing the backend to be sort of weightless. this give it better blance and weight ratio while braking.

 

[IJ.]

it will make the car more stable because the back wouldn't lift up as much causeing the backend to be sort of weightless. this give it better blance and weight ratio while braking.

WTF?

Maybe if the spring was bolted in at both ends and even then it would be the front springs that would govern the amount of weight transfer to the front and the amount of rear rise.

Please explain how stiffer rears would prevent rear lift?

My only concern is brake balance full tank V's almost empty tank as there is a HUGE difference in the amount of rears you can dial in when it's full.

 

[SySt]

Wouldn't the gas example apply the same for soft rear suspension as well?

 

[IJ.]

Syst: Agreed it would be the same no matter what springs as it's a mechanical relationship of weight over the rears tires not connected to spring rate.(Only time rate would make a difference is with soft fronts lots of transfer to the front with lots of rear rise and maybe the rear geometry changing giving less tire contact patch)(Shock valving on extension plays a bigger part in controlling rise)

eg: I can't think of a race class that doesn't reset balance/bias for full tanks.

 

[Spiv]

I have been wondering why all the springs for our cars provide a MUCH stiffer front spring than a rear. True, a softer rear promotes traction better while launching. I do feel the front should be stiffer than the rear on most cars. A stiff front end seems to promote understeer.

My roommate is big into drifting. Some of his friends are sponsored and they are all good drivers. Why this is significant is that he has ALWAYS liked a stiff rearend to break the car loose and he rarely uses "power over" techniques, he generally uses weight transfer and brake power to break a car loose. Also, a LOT of springs available for the usual drift cars have a stiff rear, even though the front is still stiffer, the ratio is far less.

You've pretty well accidentally answered your own question. Drifting you're trying to break traction, not improve handling. The soft springs they provided were done to make the car feel more controllable and overall better handling. If you tighten the rears up too much it will break free easier on entry.

You can always buy a really tight set of springs and only install the rears, or get a coilover setup with independent preload adjustment and preload the crap out of them.

 

[SySt]

LOL, have you ever driven a car with max preload on coil overs and totally stripped out? My roommate's 240 was that way. He got stock all the time because one of his rear wheels was off the ground.

I know what you mean about breaking traction easier. However many complain about the under steer characteristics of our cars. I think stiffening up the rear a bit would provide us with decent streetability and stability but give a better turn in response.

 

[IJ.]

Torsen Diff fixes the understeer really well in our cars!

 

[SySt]

I imagine thats possible. Though I have heard the Torsen diffs out of the 1JZ supras are not stout enough to sustain nice hp numbers. Especially if I plan on running an LS1/LS6.

 

[IJ.]

I think it's only a problem under high shock loads.

ie: Race launch with sticky tires both of which won't happen in my case .

 

[Nick M]

I have been wondering why all the springs for our cars provide a MUCH stiffer front spring than a rear. True, a softer rear promotes traction better while launching. I do feel the front should be stiffer than the rear on most cars. A stiff front end seems to promote understeer.

My roommate is big into drifting. Some of his friends are sponsored and they are all good drivers. Why this is significant is that he has ALWAYS liked a stiff rearend to break the car loose and he rarely uses "power over" techniques, he generally uses weight transfer and brake power to break a car loose. Also, a LOT of springs available for the usual drift cars have a stiff rear, even though the front is still stiffer, the ratio is far less.

You answered your own question. Drifting, or gross oversteer is not what the engineers want. Or you on the street with traffic. You want balance between the front and rear.