why are stock front springs lighter than rear on r32 gtr

[Scooby]

Guys;

Many aftermarket springs seem to be heavier in the front than the rear for reasons ie - ENGINE is there - that make sense.

However the stock spring rates are the opposite, the front is lighter than the rear. one explanation is that this reduces squat under acceleration, which also makes sense.

Does anyone know for certain why this is?

Regards

[Sydneykid]

Reason #1. Movement ratio and leverage ratio, they are different front to rear. The spring rates are therefore not directly comparable. The chassis only sees the spring rate at the tyre, it doen't matter what the rate of spring itself is.

Reason #2, the front can tolerate a much higher spring rate than the rear before it looses traction. If you went up substantially in the front spring rate and still kept the factory balance front to rear, you would have a wild oversteerer. It would also not power down very well.

Reason #3, you can't look at the spring rate in isolation. The stabilser bar rates are also important and the front bar has more anti roll than the rear.

Reason #4, the damper rates are also relevant.

Reason #5, as are the relative anti dive and anti squat geometry.

Reason #6. the front and rear role centres and centres of gravity are quite different. This is particulalry evident in the GTR, GTS4 and Stagea where the roll couple is not the same as the GTST, GTS, GTT etc. This is due to the front/low weight of the 4wd hardware and the altered front suspension geometry necessitated by the need to accommodate the drive shafts.

There are a couple more, but I think I that's enough for this post.

[Scooby]

Thanks SK, unless I'm missing something you've explained why the front springs are heavier than stock in aftermarket applications.

But why then are stock springs softer in the front? Wally factor?

Regards

[Sydneykid]

  Scooby said:

Thanks SK, unless I'm missing something you've explained why the front springs are heavier than stock in aftermarket applications.  

But why then are stock springs softer in the front? Wally factor?

Regards

Refer to Reason #1, the stock front springs might be softer, but the front tyres don't see it that way.

[Scooby]

Thanks SK, that makes sense. One last question; at what point (if there is one) does the transition occur in set up from greater front rate than rear rate (ie stock) to harder front rate than rear rate (as per what seems to be aftermarket)

Regards

[Sydneykid]

  Scooby said:

Thanks SK, that makes sense. One last question; at what point (if there is one) does the transition occur in set up from greater front rate than rear rate (ie stock) to harder front rate than rear rate (as per what seems to be aftermarket)  

Regards

I am not sure that there is a "point", more like the font rate slowly catches up to the rear as you increase the rear spring rate. The changeover occurs when the rear can't tolerate any more spring rate and traction is reduced. Personally I don't see a need for rear springs much over 250 lbs per inch. You really have to be using full on racing slicks before the car will benefit from a higher spring rate than that. Even using "R" type tyres, 250 is at the upper reaches. However on the front there is benefit up to 400 lbs provided you can tolerate the ride deterioration and the roads (even tracks) are smooth enough.

So maybe you could says the change over point is around 200 to 250 lbs per inch in the rear. Don't go any higher there, but you can go higher in the front.

Hope that answers your question:cheers: