I must admit that I struggle to rationalise the spring rates combining in this situation.
I’m struggling too.
The only way I can see rates accumulating is if the springs were permanently mechanically connected in the system rather than independent. Then if one went into compression and the other in tension the rates would combine? [/quote]
I can see the logic of that Roger, even if it's not the case.
Let's suppose we have a stub axle with equal rate springs on a test rig. If both springs are just at the static unloaded length, but touching the stub - my logic tells me that to move the stub either way - the resistance would be the rate of one spring, not both combined.
So now if we shorten the kingpin so that both springs are part compressed, and we move the stub, why doesn't the expanding spring assist in moving the stub against the compressing spring? Obviously the stub wouldn't move freely so clearly the rate of one spring doesn't overcome the rate of the other, but how it can be a combination is the thing which I just can't compute. I need a test rig.............
