Wildguzzi.com
General Category => General Discussion => Topic started by: amamet on November 11, 2019, 12:25:11 PM
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I’m in the process of rebuilding my forks since the seals were leaking anyway. I noticed my springs oriented differently on each fork. Is this a normal modification? I believe these are FAC dampers and wirth progressive springs. While everything is a
(https://i.ibb.co/VQtC820/4-A1-E8800-845-B-4801-A9-C4-2955-C68-BA69-C.jpg) (https://ibb.co/VQtC820)
part, do I need to take the springs off the damper and measure anything? I’m not familiar with rebuilding forks… Yet. And yes, if you notice the fork tubes are quite pitted, I am ordering a new pair
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It really doesn't matter which way round the springs are installed. Maybe someone had doubts, so put one each way to hedge their bet. No need to disassemble farther unless you'd like to check damper function.
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Supposedly springs are to be assembled with the loosely wound side up. I never could figure out how that could possibly make any difference.
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Most progressive springs work by having a smaller gap between a portion of the coils so that they bind which cause the wider portions of the springs to stiffen up and increase the spring rate. A spring is a torsion bar that is curved into a coil. The wire twists from one end to the other. Twisting a short wire of a given diameter is harder than twisting a longer one over the same angular distance, so shorter wire makes stiffer springs. The spring wire itself is the same diameter from end to end, which, if all the coil spacing is the same, the coils will bind at the same time, have an equal spring rate throughout the distance of the stroke. By closing the space for a few coils at the end of the spring, which prevents them from twisting any more and that makes a shorter functional spring (wire), increasing the spring rate. Some shock manufacturers will use a short softer spring on top of a longer stiffer one. It gives a similar result, with a little more abrupt transition between the harder and softer rates.
It doesn't really matter which way they are put on, but I usually put the closer coils on the top to reduce unsprung weight as they compress.
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Most progressive springs work by having a smaller gap between a portion of the coils so that they bind which cause the wider portions of the springs to stiffen up and increase the spring rate. A spring is a torsion bar that is curved into a coil. The wire twists from one end to the other. Twisting a short wire of a given diameter is harder than twisting a longer one over the same angular distance, so shorter wire makes stiffer springs. The spring wire itself is the same diameter from end to end, which, if all the coil spacing is the same, the coils will bind at the same time, have an equal spring rate throughout the distance of the stroke. By closing the space for a few coils at the end of the spring, which prevents them from twisting any more and that makes a shorter functional spring (wire), increasing the spring rate. Some shock manufacturers will use a short softer spring on top of a longer stiffer one. It gives a similar result, with a little more abrupt transition between the harder and softer rates.
It doesn't really matter which way they are put on, but I usually put the closer coils on the top to reduce unsprung weight as they compress.
The best way, at least to my simple mind to understand compression (or tension) spring rates is to imagine the spring wire is unwound and straightened out. Now lay the wire horizontally and model it as a cantilever beam with a single point load on the very end that is not fixed.
Thinner wire deflects more, longer wire (tighter wound coils or larger spring OD) deflect more, lower spring rate.
Thicker wire, shorter wire deflects less, higher spring wire.
Anything more than that confuses my puny brain.