I have heard of progressive springs and this concept makes sense to me. Why does Race Tech recommend Straight Rate Springs for forks?
When setting up the spring forces in a bike you want a setup that is progressive enough yet not too progressive. A setup that is not progressive enough will have a tendency to feel too harsh yet when a big hit is encountered bottoming occurs. A setup that is too progressive will either drop through the travel feeling mushy and then feel as though it hits a wall or can feel good until it hits that wall. On front forks there are two forces we consider to be “spring” forces. First is the coil (mechanical) spring and second is the force due to air pressure and oil level. Even if you run zero air pressure the oil level causes the pressure to increase as the forks are compressed. By its very nature this increase in pressure is very progressive. We have found that in combination with a straight wound spring we have a good level of progressiveness. If we want more progressiveness we simply raise the oil level.
