Progressive fork springs vs Traxxion

[utbrenner]

What are the differences with just basic fork springs between these 2?

[Blind Spot]

Are you referring to the difference between progressive springs and single rate springs?

Progressive springs get stiffer the more you compress them (provide more resistance to being pushed the more they are pushed)

Flat rate springs require the same amount of energy to compress the spring for a given distance throughout the stroke.

For example, .95kg/mm springs require .95 Kilograms of force to compress the spring 1 mm (there's two so you have to do that math too). That's the same whether you're at the top or bottom of travel; if you've compressed the spring 10mm, adding an additional .95kg of force would compress it another mm VS a progressive spring may require .85 kg/mm of force at the top of it's stroke and 1kg/mm at the bottom (arbitrary numbers).

Now, with flat springs the damping requirements of the suspension don't change much through the stroke. That's not the case with progressive springs, the further through the stroke you go, the less compression damping you need, on rebound you need more rebound damping. Unfortunately it's difficult to get suspension damping qualities that will perform in an ideal manner throughout the suspension's stroke with progressive springs.

[utbrenner]

Originally Posted by Blind Spot

Are you referring to the difference between progressive springs and single rate springs?

Progressive springs get stiffer the more you compress them (provide more resistance to being pushed the more they are pushed)

Flat rate springs require the same amount of energy to compress the spring for a given distance throughout the stroke.

For example, .95kg/mm springs require .95 Kilograms of force to compress the spring 1 mm (there's two so you have to do that math too). That's the same whether you're at the top or bottom of travel; if you've compressed the spring 10mm, adding an additional .95kg of force would compress it another mm VS a progressive spring may require .85 kg/mm of force at the top of it's stroke and 1kg/mm at the bottom (arbitrary numbers).

Now, with flat springs the damping requirements of the suspension don't change much through the stroke. That's not the case with progressive springs, the further through the stroke you go, the less compression damping you need, on rebound you need more rebound damping. Unfortunately it's difficult to get suspension damping qualities that will perform in an ideal manner throughout the suspension's stroke with progressive springs.

So the Traxxions are a better choice hands down

[Wonger]

No, they may just be different/easier to set the valving appropriately. If the valving could keep up, the idea of very light compression in the first 20-30mm of travel is a solid one that could make for a very smooth ride.

[fzwhat]

Originally Posted by Wonger

No, they may just be different/easier to set the valving appropriately. If the valving could keep up, the idea of very light compression in the first 20-30mm of travel is a solid one that could make for a very smooth ride.

I agree with this for 'ride comfort' purposes (the 'if the valves...' part being very important), but progressive springs are actually just a compromise that allows acceptable performance for a wide range of rider weights - better performance can always be had with properly selected fixed-rate springs (IMHO).

Jim