To clearify what Lizard said, the forks act together on the triple, and it keeps them the same length. Now the one with a stiffer spring (or more oil, thicker oil, etc) may be taking on more of the bike's weight, but it would take something bending/twisting for the bike to pull to one side or the other because they act as one system. Your mental experiment is flawed. Consider this system: This is similar to the forks on a bike. To assist the visualization, image that the black object can slide up and down the blue pipes while the blue pipes stay stationary. The forks act in a similar way. Now back to the visualization, try to slide one side of the black object further than the other. It wont happen, because it pulls the other side with it. Now pretend that the black object is two forks connected by a triple. For your experiment to work, you would have to force your metal bar to always be perpendicular to the two springs is that clear? (I have to ask because I think a little... "differently" sometimes, )