Quote:
Originally Posted by MaysEffect
Good info, and also good point about it being plusher oppose to softer. That i believe is the correct term. But this doesn't explain how it changes its specific force output when comparing two similarly rated springs. It only explains for any specific rate, you have less mass and subsequently more available travel. Would this actually make 400ib/in rated spring respond differently? Possibly, but what is being changed here dynamically? Wheel rate? The springs mass is balanced 50/50 between unsprung and sprung mass, so 2-5ibs loss in mass on the unsprung side would make a huge difference on its inertia over bumps. The other caveat is fatigue resistance and resistance to sag. Both of these go back to what i said earlier.
So in actuality the new spring would actually be stiffer, possibly resulting in a smoother more responsive wheel control. This intern is misconceived as "softer", but as you pointed out, it is actually "plusher". 
Similarly to reducing the mass by adding smaller diameter and lighter wheels and tires, the overall change here is a reduction in weight and inertia. |
I don't think there is a difference in force output andI don't believe anyone here is actually thinking that. I believe this whole thing got derailed because of nitpicking terminology. I don't believe anyone is actually claiming swifts are "softer" what they mean is they ride more sensitive and give a perceived "softer" or probably more appropriately named "plusher" ride. This allows a user to jump up one rate without having the added "harshness" when doing so.
As you stated yes they will have less unsprung mass (although I'm not actually sure if that's right, is 50% the spring considered unsprung?) allowing the suspension to react quicker and just like wheels/rotors and everything else which all drastically help suspension.
As for an old vs new spring the spring on my bike was only one season old and had about 1-2 turns of preload (which in less than 1/16 and in on this shock) and unlike a vehicle there is no load on them without a rider (the rider is the main mass) so as for it being fatigued after only one season and being my dedicated dh bike it only sees about 6-8 trips a season so I highly doubt it was fatigued when I changed to the alloy spring.
As stated though it is a very slight difference but I'll bet the weight savings difference for this size size spring isn't as much as a car spring.