ATV Rear Suspensions
ATV suspension has been evolving over the past 2 decades. There has been constant improvement with new and better shocks and suspension components constantly being developed. Several of the notable innovations to hit this industry include progressive spring rate combinations from Works Suspension, extended A-arms from both Leager and JP Racing (now known as Lonestar), ProTrax front ends by Leager, CR500 linkage setups from Leager, and no link setups from both Roll Design and Lonestar. Most of the innovations have evolved into even better product and setups today as the concepts that brought us these innovations in the first place became better understood and companies continued to build and improve on these concepts.
One example of this is the “Long Travel” front ends that gave shock builders more room to work with when designing progressive rate spring stacks. Some of the innovations were very successful, but not for the reasons that are first apparent. A good example of this is the no-link rear suspension that was brought to us from Roll Design and Custom Axis. This setup worked well and was very successful, not because of the no-link setup, but rather the fact that it was one of the best setup rear ends in its day. With notable input from Mike Hallock , Bill Balance and others, this setup was designed with better attention to detail such as the correct amount of up travel, the correct amount of down travel, and a better combination of springing and valve setup. Anytime this attention to detail is given to something and it is tested and developed to this extent, it will inherently be successful, and remain an industry standard until someone steps up with a better concept and applies it with the same attention to detail and develops it to a higher level. A better concept alone will not succeed without the proper development.
A good example of this is the stock rear suspension on the YFZ450. While the rear linkage is derived from the very successful linkage setups on 2 wheelers, it does not meet everyone’s needs. If you ran a tall tire like used in XC racing and tried to lower your bike, you then spent to much time in the extreme up travel part of the suspension where the progression rate was very high. This gave the quad a feeling of kicking and bucking, while never actually bottoming at the shock. Elka manufactured a link for this that lowered the progression rate. In the near future there will be many companies offering linkages to help setup quad suspension correctly.
Why would we want a progressive rate rear linkage setup when the no link rear setup worked so well?? Take a look at the 2 wheel side of this sport. The Big 4 vs. KTM. For some reason KTM has chosen to stick to a no-link setup and has had to build a more exotic shock setup to compensate for the lack of progression. What does a progressive linkage give us?? It allows us to have a plusher ride in the main part of the travel while still giving us very good bottoming resistance in extreme conditions. How does it do this?? The shock actually moves faster for the same amount of wheel travel as the rear wheels get close to their maximum up travel. This extra shaft speed acts to give the same effect as if we stiffened the valving just before we bottom out the quad. What KTM did to compensate is install a moving internal shaft that actually does stiffen the valving when close to bottoming, and they install a progressive rear spring. Why would someone not want progressive rear linkage?? If the progression rate is to steep – it can be as bad or worse than having no progression at all. If all you ever hit is 2-foot whoops, a no-link suspension could be dialed in to work very well for that but would bottom out badly on a 40-foot flat lander. Or a no-link could be dialed in for 40-foot flat landers but would then be very stiff in the whoops. With progressive linkage suspension that is setup correctly, it is possible to tune the rear suspension for a much larger range of conditions. With a no link rear suspension – it is very easy to add some progressive resistance with a variable rear spring setup. However we still have out hands tied as valving goes with currant ATV rear shock technology.
Progressive rear linkage suspension in not automatically better then no link, but has the potential to be better if the linkage is designed correctly for its use and the shock is dialed in for it.
If you are spending your hard earned money, don’t buy a new linkage just because it is better, but rather buy the correct linkage for your needs. Be sure to get the progressive rate linkage that meets your needs.