bokals

Front wheel drive cars handle different from rear wheel drive cars obviously.

BUT

Theres alot of controversey over rates, Some say stiffer rear rates belong on drag cars, while circuit road race cars have a stiffer front rate.

Some companies like PIC think road race cars rotate better with a stiffer rear rate. Tein does not

Japanese Coilovers, I.E Tein, Ksport/function, Tanabe etc Have stiffer spring rates in the front and lower rear rates.

Example
Tein Monoflex 14k/9k rear
Ksport 13k/6k

Also what comes into play is Sway bar sizes etc also.

I am running PIC coilovers
There rates are different then Teins/Ksports etc.

8k/10k
14k18k
12k/16k



My setup
8k/10k
21 mm rear sway

Car rotates real nice.

Everyone has there own personal preference when it comes to spring rates. Some like a stiffer front end, others stiffer rate in the rear. What does having a stiffer rate in the rear do for a car that is fwd?

Thank You

Progress Technology

In short, a stiffer rear spring will help the car rotate more. A softer rear spring makes for a more comfortable ride.

bokals

What about the front?

14k front 8k rear

Whats that doing other then having a smooth ride

Progress Technology

Well there's a lot more factors involved here than just spring rates. Suspension geometry, weight of the car, anti-roll bar size, etc.

The front spring you want to find a happy medium where you are reducing the body roll but at the same time not sprung so high where you're going to lose traction over bumps.

Egezzy

iTrader: (2)

this also has alot to do with the valving of the shocks too.

i am on my phone. i will type more in depth in the morning.

PIC Performance

There's no controversy over spring rates - there is simply more than one way to get a car to turn, and different performance needs require different setups. We've chosen one route, others choose a different route, and at the end of the day there is much more to how well a car and driver perform on the track than a spring rate. Spring rates are only one part of a complex equation involving the shocks, swaybars, tires, chassis, driver, etc.

Egezzy

iTrader: (2)

well what pic wrote is basically very short clif notes of what i was going to say. it.s too early in the morning soooo ill leave it at that for now. lol.

ps pic you have pm.

Flint707

Stiffer springs in the rear are for drag racing purposes simply because on a launch, all the weight gets distributed to the rear.
You don't launch on a road race track, and most of the weight is distributed to the front when breaking and turning at the same time, hence stiffer rates on the front of the car of a road race setup.

Egezzy

iTrader: (2)

so weight transfer doesnt apply in road racing??

Flint707

It absolutely does. But launches transfer weight to the rear, breaking sends weight to the front. There is no breaking in drag racing, however there is heavy breaking in road racing.

turbociv910

Japanese shock companies have the soft rates in the rear, but are always running a very large sway bar to compensate.

Egezzy

iTrader: (2)

ok. well acceleration also transfers weight to the rear. and in road racing there is also of accelerating.

Wai

Stiffer front vs stiffer rear has been a big debate in the past, and what it comes down to is the complete package. JDM race cars with stiffer front springs also comes with things like staggered tire sizes, wider track in front than rear (with spacers or low offset wheels), much more negative camber, clutch pack LSD, much lower ride height, etc.

The US race cars with stiffer rear springs approach it differently, and it works very well in compromising the variations in track surface condition, and DOT R compound tires "generally" not as grippy as the JDM slick tires.

That's not entirely true. They run bigger bars, but in no way as big as those crazy PIPES they run in the Honda race cars here in the US. The JDM theory is that, the thicker the bar, the more "independence" you take away from the L/R suspension.

Flint707

Correct, but corner exit acceleration is very different from an 8k launch on a car that makes ton's of horsepower.
Accelerating out of a turn is a lot smoother than a dead stop launch.

Egezzy

iTrader: (2)

i dont know how you define smoother since when accelerating out of a corner there is alot of weight on the outside rear tire. i agree that the type of acceleration is different obviously in g loads/direction of the load. but point being the physics of it is the same...weight transfer loading the rear.

Flint707

They physics are very much different. Taking a turn at 65mph and having weight transferred more to one side is entirely different from launching a car from a dead stop. The weight gets distributed to the rear evenly with a launch, a chassis gets some kind of body roll meaning the weight gets transferred to one side of the car rather than a portion of it.

Egezzy

iTrader: (2)

thanks for clearing up what i just said. lol.

Flint707

Are you serious? You said it was the same (physics wise), when my response was a rebuttal. Where is the similarity?

Egezzy

iTrader: (2)

yes i am serious. reread the whole post. and yes the physics is the same. weight being transfered to the rear.

i guess long story short is i have driven front bias and rear bias sprung cars. i myself like a rear bias feel alot more. is that for everyone. NO. is it for me with the current setup i have. YES.

i am just debating with you because you say rear bias should only be on drag cars. which is not true. i along with many others track or autox rear biased cars.

Flint707

I never said it should ONLY be used for a drag car, but often is. Bottom line, people can put a different rate on every shock... and if they like it like that, then they like it like that. It's all about preference.

Egezzy

iTrader: (2)

take out the term mainly and well call it even. lol.

Flint707

Ta Daaa!!!

string

I run rear biased with no front swaybar and I like it much better than any front biased FWD I've driven. My car is road registered so I have follow rules about ride height. This means I have plenty of front suspension travel for my soft front springs. The track I go to also has a top-speed of around 150kph on the straight and an entry of around 90kph to the first corner so braking isn't all that heavy.

There's more elements to balance than springs alone - for starters: not all of the lateral weight transfer happens through the springs so it is only one element of the balance.

I can understand how the Japanese tuners get their setups - they run very low and very stiff at the front. If you have a 1200lb/in+ front spring you can you really expect to run stiffer at the rear? Sacrificing a bit of rear spring [less slip angle] and making it up with a narrower track and skinnier tyres seems fair to me. If it's faster then it's faster. Lowering the centre of gravity all else equal is a very good thing.

Egezzy

iTrader: (2)

yeah while on the topic of "jdm" setups and all that jazz. there is an old article in super street about the top fuel civic. look at their wheel/tire size setup.

nukeONE

so what a good spring rate to run on a ek?

i drag race.. but i want to get into road racing too.