Occie gets her rear end up!

Didn't even notice the spacing was different at each end. What difference would that make ? How can hey bit fitted upside down ? Surely it still compresses at the same rate. Will have to check mine now
 
Harvey is right, and I can think of an engineering explanation. Engineers always try to minimise the masses that are subject to movement. In the case of suspension, everything attached to the car is described as "sprung" and everything to the road wheels as "unsprung". So you're trying to minimise unsprung weight. In this case the end of the spring attached to the car is sprung and the end attached to the trailing arm unsprung. So we want the close spaced coils at the sprung end ie next to the body at the top.

The same logic applies to Harvey's example of valve springs. The moving part is the rocker arm, the stationary the head - so the heaviest part of the spring goes towards the head.

Chris
 
Just had a look at my old springs and can't see any difference in the coil spring spacings, measured them out and they are the same at both ends, the W/S manual does not mention anything about right way up, also did search in tinternet and found a Honda owner who's springs were fitted upside down at the factory, Honda spotted it on a service 3 years later, they fitted them correctly but said it doesn't make any difference it's just they have a dot which goes to the top. Had a look under my car and can't see any difference in the gaps between each coil, mine also from Ian. I can't understand what Chris is saying, in my eyes a spring will compress the same distance either way up. Am I missing something here.
 
Yes I think.... You are talking small differences but the weight in the spring is at the top....

Rich.
 
Happy Days - the bit you are missing is that Stan has a set of Ian's variable rate rear springs. Yours will be standard springs. The variable rate springs have different coil spacing at one end t'other. Yours have the same spacing throughout. So yours can indeed be fitted either way up. Stan's are heavier at one end than the other and so the heavy end (closest spacing) goes towards the body.

Chris
 
happy days said:
Ahhhhhh mine from Ian were the heavy duty ones, so thats different from Stan's ?
Click to expand...

Hi Mick,

If you've had HD springs from Ian, then they are indeed progressive i.e. variable spring rate through the travel.

Spoke to Ian this morning and we've both arrived at the same conclusion as Chris (and Harvey), but only on the basis that with the closer coil spacing at the top, the spring resistance is likely to increase as the load increases.

This may be totally spurious thinking, and maybe it doesn't make a big difference whichever way they go, but that's the way I'll fit them.

Also Mick, I'm not sure whether the variation in coil spacing will be so obvious once fitted. :?:
 
The diferent gaps might not be so apparent when they're compressed and fitted to the car Mick.

I have a different theory on the correct way to fit progressively wound springs in order to reduce the unsprung mass - the narrow spaced coils should be at the bottom, ie on the trailing arm.

This is because it's the softest part of the spring which will move first when you hit a bump - it's the trailing arm that moves not the car body. The stiffer part further up the coil (closer tot he car body) will only move as you hit bumps with bigger force or height. Fitting them with the narrow spacing toward the body means that you'll have to move the stiff part of the spring to compress the soft bit at the top on small bumps effictevly using it as a push rod - hence fitting the narrow spacing at the bottom to reduce the unsprung mass to a minimum and have a supple ride over small ripples.

Of course, the spring will still work when fitted either way and I doubt you could tell the difference.

Good work so far Stan, the clock's ticking on the way to spring now.
 
One minor flaw with that Paul - I was always under the impression that the stiff bit was the close spaced coils?

Chris
 
If the spring is made from a single diameter material (i.e. it the metal doesn't get thinner at one end), then the whole spring will be one rate.
The Progressive aspect comes from the closer wound coils binding and hence no longer "springing", in the same way that cutting coils from a spring makes it stiffer as well as shorter.

Obviously that has no bearing on which way up you put them, and as testrider says, I don't think you would be able to tell the difference either way up.
 
Mmm. Operating beyond my knowledge here, but I don't think that's right, Richard. The angle the wire lies at must make some difference. Have to go away and have a deep think.

Chris
 
You guys know more than me, checked drivers side and it was " upside down" this has now been corrected. But the manual says only tighten the nut and bolt on lower suspension link to de dion tube when the spring has been compressed to " approximate static unladen position" explanation please from anyone
 
That's due to the suspension bush. They don't rotate in the housing, the rubber just stretches, so if you tighten them up before putting the car down they get over-stretched when the car hits a bump. Sitting the car down before tightening puts the bush in it's mid position to allow for bump and rebound.
 
But is their enough access when the wheel is on and the car is on the ground. The W/S manual says torque It up before putting the wheel on. Even they say to approximate unladen position
 
I'm planning to get it all together, then up onto ramps at all 4 corners before squidging under to do the final torqueing up.

Wouldn't be happy jacking up the De Dion to simulate it.
 
chrisyork said:
One minor flaw with that Paul - I was always under the impression that the stiff bit was the close spaced coils?

Chris
Click to expand...

No, the wider the spacing between the coils, the stiffer the spring for a given wire diameter. So on a progressive spring the section with coils close together is easy to compress. You can see this by simply pressing down on a spring when it's off the car. The wider spaced coils barely compress until the shallower ones are coil bound.
 
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