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Author Topic: Progressive fork spring orientation?  (Read 155 times)

potboiler

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Progressive fork spring orientation?
« on: October 28, 2013, 06:19:38 AM »
Do the closely wound coils go at the top or bottom in the front forks - I'm fitting the ones supplied by Hitchcocks for a softer ride (hopefully). Or doesn't it matter much?

Thumper

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Re: Progressive fork spring orientation?
« Reply #1 on: October 28, 2013, 06:56:54 AM »
Technically, it should make no difference. Typically, however, people often put the softer rate coils on the bottom. The softer rate portion of the springs will compress first, regardless of whether they are on the top or the bottom. If you turn the fork upside down and compress it, the spring rate would not change. And, BTW, you can always ask Hitchcocks tech support if they have a recommendation.
« Last Edit: October 28, 2013, 06:59:24 AM by Thumper »

barenekd

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Re: Progressive fork spring orientation?
« Reply #2 on: October 28, 2013, 12:10:07 PM »
Most progressive springs work by having a smaller gap between a portion of the coils so they bind which cause the wider portions of the springs to stiffen up and increase the spring rate. Understand that a spring is a torsion bar than 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 make 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 give 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 where the shaft is to possibly keep a bit of dirt out.
Bare
« Last Edit: October 28, 2013, 12:24:41 PM by barenekd »
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potboiler

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Re: Progressive fork spring orientation?
« Reply #3 on: October 29, 2013, 03:02:00 AM »
Hitchcocks have just told me that the 'soft' (closer coils) go at the top.