Spring question ?

[bccap]

Sorry, I have no intention of changing the oil. Was just commenting on what I would do if I was doing the job now. I think I would have put those Progressive springs in as well. But at the time I didn't want to wait or spend the money.

[7981GS]

You can always add a spacer to increase the preload.

Daniel

[RichDesmond]

Really?

I thought that the tight ones compressed first.

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Actually, all the coils compress together, but the tighter end coil binds first, reducing the effective length of the spring and making it stiffer.
The spring has no idea which end it's being compressed from, the only advantage to putting the tighter coils up top is that reduces unsprung weight by a tiny amount. Completely insignificant effect in a motorcycle fork.
Put them in with the tight end up, down, mixed, whatever, you'll never feel a difference.

[Agemax]

Actually, all the coils compress together, but the tighter end coil binds first, reducing the effective length of the spring and making it stiffer.
The spring has no idea which end it's being compressed from, the only advantage to putting the tighter coils up top is that reduces unsprung weight by a tiny amount. Completely insignificant effect in a motorcycle fork.
Put them in with the tight end up, down, mixed, whatever, you'll never feel a difference.

how does it do that then? considering the springs are part of the mechanics that all the unsprung weight is attatched to!

[RichDesmond]

how does it do that then? considering the springs are part of the mechanics that all the unsprung weight is attatched to!

The top of the spring is 100% sprung weight, the bottom of it is 100% unsprung. A linear spring has its weight evenly distributed over its length, so 50% of the weight is unsprung. A progressively wound spring has a heavy end though, the one with the tighter coil winding. So if you install it with that end down you might end up with 60% of the total weight being unsprung.
A pair of springs weighs around 35ozs, so 10% of that is 3.5ozs. Compared to the weight of the wheel, tire, brake disks, calipers, fork sliders etc. that's insignificant, less than 1%. Ergo, it doesn't matter which end goes up.

[Steve]

Actually, all the coils compress together, but the tighter end coil binds first, ...

That's what I meant, you just used better words.

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