Thread: Front vs Rear Spring Rates

Simply put having stiffer front springs increases understeer, having stiffer springs in the rear increases oversteer. Since understeer is seen as safer then oversteer usually manufactures will put stiffer spring rates on the front and softer ones in the rear, but that doesn't seem to be the case with Nissan and at the very least their beamed cars. This could very well be because Nissan decided to increase understeer by adding toe in prebuilt into the beam.

Now most off the shelf lowering springs seem to follow the OEM convention with spring rates, which is Rear is stiffer then front, except for coilover systems. It seems like just about all coilover sets have stiffer fronts then rears.

Here are some examples from B15 setups:
Drop in springs:
Stock SE/SE-R: 134F/212R - Rear 37% Stiffer
Stock Spec-V: 154/247 - Rear 38% Stiffer
Eibach Pro-Kit: 180F/300R - Rear 40% Stiffer
Tein S-Tech: 170F/270R - Rear 37% Stiffer
Tein H-Tech: 154F/246R - Rear 37% Stiffer

Coilovers:
BC Racing: 336F/224R - Front 50% Stiffer
Tein Basic: 336F/336R - Front 0% Stiffer
Tein SS: 336F/280R - Front 20% Stiffer
Nismo S-tune Kit: 185F/300R - Rear 38% Stiffer

I'm curious on if there is any specific reason for this? It would seem it would be counterproductive to go against the OEM route.

Usually when people get coilovers though they change the camber and toe settings, so they would resort back to more conventional spring rate bias. Just a guess though.

True, but on rear beamed cars you get nothing adjustable, and on B15's and P11's you have no front camber adjustment.

Either way, I'm working on installing Eibach Pro-kit's on my P11 to replace B&G's. I did the front tonight, I was going to do the rears but then I thought I would test something. B&G's are a good bit softer then Eibach's, so I'm trying the whole softer in the back and we'll see how she handles compared to stiffer Eibach's on all fours.

Mike K made a article about it

Nissan wants you to be comfortable, not handle well.

But by making the rear stiffer they are making it handle better .

They are compensating for the beam.

Since you still don't recognize the relationship, let it marinate more.

You missed my point, they could have left the rear to have softer spring rates. Then the car would understeer even more and handle worse. Thus they made the rear stiffer to handle better, it could have been way worse

Unfortunately, you still missed my point.

You are looking at these numbers for what the face value and not why they are what they are. (In other words, you are only looking at two numbers and saying the relationship is what it is, and not Why it is)

Tell me then, why do coilover manufacturers are putting much softer springs in the rear, while drop in lowering springs got it correct like OEM Nissan did?