For all my motor biking life I've sorta been under the impression that altering the pre load on a shock made the ride firmer or softer, but lately I've been in a bit of a quandry. My thought is, if there is say 200kg compressing a spring, that spring will be exerting a force equal and opposite to that which has been applied, so when in equilibrium, it will be exerting 200kg against the collars. Ok, so now we wind up the pre load an amount, that will apply an extra amount of force, let's say 20 kg ( Yes I know kg is a mass not a force, but if we multiplied everything by 9.8 we'd have it in Newtons, but that's not my point), so now we have 220 kg against the collars, but won't the spring just move out the appropriate amount until it's back at the 200kg reading and all that we've done is altered the ride height ? I'm sorta saying that no matter what pre load you apply, when at rest the spring will still only be supporting the mass that is compressing it. Very happy to hear opinions 'cos I'm not sure that I've got this right.
