Both the spring rate and the damping effect brake dive. A massively stiff spring would control it well. That same massively stiff spring will need a lot of rebound damping to control it. The stiff spring will change the resonant frequency of the suspension, drastically changing the ride quality for not only a stiffer ride but in a way that will transfer a lot of road iregularities to the rider. A gold wing uses a 0.85kg spring rate in the forks and not because Honda engineers are stupid. A ton of compression damping will also control the dive, that is what is happening in the intiminators. Lots of compression damping will also transfer bump energy into the rider. As suspension tuners, we want to match the spring rate and the damping profile to work together in an application and in a way that provides the correct amount of chassis rotation, bump control, rider feel and traction. Peoples preferences also vary and some folks fixate on one aspect. If a 170 lb rider puts 1.1 kg mm springs and 15 wt oil in their wee forks, the brake dive will be greatly reduced but the bikes going to ride like crap in many people's oppinion. At the end of the day, most of us will want a good degree of chassis rotation as a performance and handling benefit. Coming into corners on paved or gravel roads, I want the front to settle in a controlled manner while I am on the front brake, as I tip the bike into the corner, I am trading that fork compression from my braking load to the cornering forces. Doing that gives weight transfer and even potential advantages in chassis geometry for making the turn. Once the bike begins the turn, picking up on the throttle and the relaxing of the cornering force transfers the weight for my acceleration traction at the rear. Even the rear shock effects the "brake dive". Balance, control, traction and comfort; those are what we want to look for. I dislike anti dive suspension systems like the ols DKW I owned or the BMW link type forks that don't brake dive until I am in the corner and let off the brakes. I also personally don't like the inertia valve system for some of the same reason and others. Anyhow, I think if you have the opportunity to ride a properly setup strom, you will be impressed how smooth and controlled they can be.
All that said, if all your riding is on the freeway and brake dive is your big and perhaps only complaint, I agree with Todd, put in our competitors Intiminators with your stock springs. That inertia valve will really add a lot of control of the brake dive at the lowest cost.
Rick - Asheville, NC
Last edited by NC Rick; 10-29-2013 at 09:54 AM.