What's the difference between front and rear springs on NA?

mxfive95 · Postby **mxfive95** » Sun Dec 09, 2012 3:16 pm

Hi,

I sold my progressive rate springs and swapped them with standards. We did the change over on the spot as were swapping already installed springs. I made sure we swapped the front springs first but have a feeling the springs might have been put in the wrong way (there were many people helping out so not too sure).

The result is the front sits almost an inch hight than the rear. I haven't had the wheel Alignment yet so if the forint wheels are toed out, this might be the cause of the front sitting higher. Not sure.

Any help much appreciated. I tried google but as I'm on a mobile I'd rather ask than rack up a huge phone bill :/

Thanks

Steampunk · Postby **Steampunk** » Sun Dec 09, 2012 9:59 pm

obviously length and number of coils and hence rate of stiffness.
It's not a linear relationship either, the fronts will be much stiffer because it has to support the weight of the engine and much heavier components than the rear, not to mention more cornering loads, so the front springs are even more stiffer than the rear to compensate.

Postby **NitroDann** » Sun Dec 09, 2012 11:24 pm

Weight balance is almost 50/50, it has nothing to do with having an engine in the front, it has to do with suspension geometry, leverage ration on lower control arms etc.

However the front is longer and 50% stiffer than rear.

Dann

aka_juffa · Postby **aka_juffa** » Tue Dec 11, 2012 11:25 am

As already mentioned, the front springs are longer than the rears. Also the front damper body may have a mounting point for ABS, where as the rear doesn't
Lastly, were the suspension nuts/bolts tightened with the weight of the car on the suspension?.....if not the car will take a few days to settle.

I have also read, but have no experience with, that the bushes will suffer long term damage if the suspension is not tightened as mentioned above.

J.

RedMX · Postby **RedMX** » Tue Dec 11, 2012 5:22 pm

I don't know if this will help but for easy identification of the springs for your na8

on the na6 there is a stripe of paint on one of the coils on each spring.

Red - Fronts
Blue - Rears

This is consistent with the 2 sets of complete stock shock/spring combos I have in the back yard for the Na6 :roll:

Cheers Gareth.

mxfive95 · Postby **mxfive95** » Sun Dec 16, 2012 6:48 pm

Thanks guys.
All suspension was tightened while of the ground and my sway bay links are mania ones without bushes. The springs I put in where on an na6 with clubman bilsteins and where put on my na8 with clubman bilsteins. The car has been dríven over 1000k since and still sit higher at the front, so just going to swap the fronts with the rears. Can't see any painted stripes so guessing they've been painted over or flaked off. I'll measure the lengths, thickness and amount of coils and post up the results for future reference.

Postby **NitroDann** » Sun Dec 16, 2012 6:55 pm

The length difference is huge, AND the fronts are stiffer, if you have them in the wrong way it would be like 3 inches differences ride height.

Dann

mxfive95 · Postby **mxfive95** » Sun Dec 16, 2012 7:05 pm

It's currently 1" difference. I initially thought they'd need time to settle, or may need a wheel alignment incase the front is toed out, but its been almost a month so just going to hoist her up and measure spring thickness etc. should only take an hour.

Postby **NitroDann** » Sun Dec 16, 2012 7:08 pm

Sure, Are you sure the springs are sitting on the purches right?

Also its probably been said but the stock rubber bushes twist and so provide a spring if they have been tightened without the weight on them.

Dann

Steampunk · Postby **Steampunk** » Sun Dec 16, 2012 8:13 pm

I'm really not understanding your comments re:

mxfive95 wrote:...wheel alignment incase the front is toed out, ....

mxfive95 wrote:...I haven't had the wheel Alignment yet so if the forint wheels are toed out, this might be the cause of the front sitting higher. Not sure.

Toe has no effect on height.

mxfive95 · Postby **mxfive95** » Mon Dec 17, 2012 6:21 pm

Yeh, i'm not 100% sure it would either. but logically, If your front wheels are toed out it could create lift at the front end.

Well after checking, the springs are in the right way, so it might be the sway links. I Have adjustable end links on the front and when I'd swapped the springs I installed some on the rear. So off to get a wheel alignment.

Steampunk · Postby **Steampunk** » Tue Dec 18, 2012 10:07 pm

Okay, well... you just made it even more confusing. End links have nothing to do with ride height either. You can have the fanciest links on earth, or none at all, and it won't make a lick of difference.
do you know what "toeing" means?

The only thing I can figure out is you've confused toe with caster:

Caster DOES affect height, but very minimal.

Okay, say you've gotten everything correct, the right springs on the correct dampers front and rear (I hope you also know that the dampers are different lengths too), now it's a matter of the condition of the front dampers, perhaps they have lost a lot of the gas and is sagging. Even though the springs hold up the majority of the weight of the car, dampers also contribute.

Is it easy to push down on the car? and when you do, does it spring back up pretty quickly? to put it another way, can you make the car bounce fairly easily without using much weight to push it down?