BARE BONES: FINDING THE PERFECT BALANCE
The manufacturers have a tough job coming up with the perfect valving spec, spring rates, air pressures, linkage ratios, etc., to make everyone that rides their bikes happy. Bikes can’t come stock with one setup that works for Supercross, Arenacross, EnduroCross and now Snocross. Each of these disciplines requires extreme internal changes that have to be specifically dialed in; however, the factory engineers have to take a shot at finding one setting that makes everyone happy, so how do they do it? Let’s take a 450 and a rider who weighs between 155 pounds and 195 pounds. Within this range there are certainly different spring rates that could be applied to tailor the suspension to a certain rider, but the manufacturers have to pick one. The manufacturers’ U.S.-based R&D departments are usually tasked with making this decision. They test with riders of different weights and speeds, and they get opinions from different riders who ride different tracks. Sounds easy enough, but there is a glitch in the system. When they send all that information back to Japan, they get a memo stating that it’s too expensive to build the bike that way. To meet budget constraints, they have to tweak their optimum setup. Now the perfect bike isn’t so perfect anymore.
Over the years I have learned that it is actually possible to have one setting that can make a lot of people—and I’m talking really different people—happy. Of course, it is much easier to pick one rider and set the bike up for him (like we do with our Pro Circuit race team guys), but in the real world that is not always possible. Now, I’m not just saying this because I write a column in Motocross Action magazine, but working with them over the years has taught me to broaden my scope of thinking. MXA always has many different riders race the bikes. At times, it has been frustrating to not be able to work with just one MXA test rider, but dealing with a Pro, Intermediate and Vet at the same time taught me a lot about bike balance.
When setting up a bike to be versatile enough to be raced by many different riders, the most important goal is balance. My first experience with this came from working with teams that raced Baja and other offroad races where multiple team riders must share one bike. I had to focus on internal valving specs and internal parts that exhibited a good balance of both compression and rebound in the front and in the back. With both the MXA test riders and offroad teams, I found that if I could get the forks and shock to work in harmony with each other, it was possible to apply a middle-of-the-road spring rate to complement the fore and aft balance. Suddenly, you have a bike that is very comfortable no matter who is riding it. It may be a little on the stiff side or on the soft side, but anyone can ride it and feel comfortable. With a few clicks here and maybe a turn on the spring preload there, the inherent balance of the chassis is retained, whether the rider is fast or slow, young or old.
Is it possible to have one magic setting for everybody? No, but it is possible to have one ballpark setting that is close enough that it can be tuned with minimal adjustments for a wide range of racers. Is it better than suspension set up for a specific rider’s speed, weight and track conditions? No, but it is still based on finding the perfect balance.
Jim “Bones” Bacon has tuned the suspension of the biggest names in motocross, including Jeremy McGrath, Ricky Carmichael, Ryan Villopoto and Adam Cianciarulo. If you have a suspension question, send it to [email protected]