toplessPolak

Car Analogy

The stiffer rear springs will understeer less. That is the configuration of the original ap1 cars. 'Nuetral' balanced.

Since the majority of the customer base for this car was raised on front drive sport compacts, and terminal understeer, too many cars were spinning out and wrecking. So each iteration of the car went more and more front biased, towad familair understeer.

Then the CR took it a step further. Its the most front biased of them all. Turns out that setup is faster around a track, if not as much fun on the street. In the great tradition that if its good for racing, it gets used on be street, even if its detrimental, this seems to have become the go to standard for our cars. At least on this continent.

We have well researched and documented specs for factory spring rates for us market S2000's. I wonder if the same factory rates were used worldwide...

Chibo

Nah, he's got a point. Japan tuners do some really weird things with the spring rates when they set cars up. In this case, I'd guess that the car has a staggered tire setup, rather than most of the US running a square tire setup, which leads to how some of us run stiffer springs in the front than the rear.
The other thing is you don't really know what they are doing with the valving.

I don't buy the 'Japanese tracks are glass smooth' thing as reasoning (they aren't). I can buy them wanting to be more inclined to oversteer on very tight roads / tracks so they can get the car to rotate, but that can be done through other methods than huge spring rates.

Chuck S

"most of the US running a square tire setup" ?? Where do you get this idea from? Or am I misreading this?

Oversteer is slower around any set of curves, racetrack or street. Drifting -- oversteer carried to a stupid extreme -- is much slower.

-- Chuck

Chibo

Head out to a trackday with a bunch of modified S2000s, almost all will be square. Just because the setup is square doesn't necessarily mean it's overly inclined to oversteer.

Slowcrash_101

Higher spring rates in the rear because they use more aero, or run lower ride heights. Springs determine how much the suspension moves, the dampers determine when it moves. And higher rear rates don't necessarily mean more oversteer, the motion ratios lower the spring rate, so even if the rears springs are a little stiffer, the motion ratio in the rear is a little larger than the front, therefore the overall wheel rate will be the square, if the spring rates are square, then the wheel rate will be front biased.

Don't worry about the spring rate, worry about the wheel rate, that will tell you how stiff your suspension actually is.

Chibo

I'm thinking in relation to spring rates run commonly in the US. 900lb/in up front isn't all that uncommon here, but 1100lb/in in the rear kinda is. Perhaps they've changed rear suspension geometry and altered motion ratios, which is possible.

I guess it's just hard to get a complete picture.

Afterfire

I dont see anything that denotes whats front and rear. Dont the Japanese read right to left. Unless that overlay is meant for outside Japan. Ive also seen typos on those overlays before so its possible theyre not always 100% correct. Just an optional theory.

thomsbrain

Don't assume that the cars are "oversteery" simply because they have stiffer rear springs than fronts. Springs are just one part of the tuning package.

They set up with the rear springs stiffer because they are tuning their suspension based on staggered ride frequencies (a function of wheel rate, target speeds, and motion ratios), which is the way you are supposed to do it. If you want maximum grip from a car with little to no aero (including any street car, even an S2000 with track aero), you start with stiffer rear ride frequency and tune everything else around that to achieve the desired handling balance.

The stiffer front springs you see on common off-the-shelf coilovers sold in the US are side effects of an attempt to add stability to the handling balance without changing anything else about the car (bars, tires, geometry, aero). That's a back-asswards approach to grip, but coilover manufacturers have to go with the assumption that you aren't smart enough to tune the rest of your car to achieve the desired balance. So they just play it really safe and push the car more towards understeer, even though that approach leaves grip on the table. Then on the forums, everyone goes "the car feels more stable now with these new coilovers," so everyone incorrectly assumes that means it's the fastest setup. You have to understand that the stock sway bars are sized the way they are because the stock suspension is too soft (grip is compromised for comfort), and they are forced to use big sway bars at both corners to keep the roll in check, instead of simply using them as fine adjustments for handling balance. The issue is further complicated by the autocross people, who prize transitional response over steady-state grip, and therefore do all kinds of weird shit with their spring rates and sway bars that aren't ideal for a track car.

Fat Cat Motorsports is one of the few coilover companies marketing in the US that's willing to shoot straight on this topic and deliver the "bad news" that tuning for grip means rethinking the order in which you make changes and rethinking the role of the sway bar from a stock street car (roll control) to a race car (small adjustments to balance). They sell suspension packages complete with appropriate sway bars so that they can use the correct spring rate staggers. I've never used their products but they are respected in the Miata world. Also check out the Autocross to Win book and website for additional info on how to tune a suspension for grip. This was also the approach to suspension used by Gordon Murray for the McLaren F1.

As for me, I built a spreadsheet, targeted my frequencies based on desired speed for flat ride syncing, and had my Ohlins rear shocks custom-valved so that I could run the appropriate stiffer rear springs than the fronts. Then I fine tuned the handling balance with an adjustable front sway (no rear sway needed at all) and I've never once questioned the decision.

andrewhake

Nothing strange about it at all. People in the US are the ones running strange spring rates and setups. Stop listening to autocross people when setting up your track car.