LINKAGE ARM 143.75MM Pro Circuit’s Linkage Arms are CNC-machined from billet aluminum and are designed to stiffen up the initial linkage curve and lower the chassis, making the bike much more stable. This will also help eliminate the initial loose and wallowy feel. Turning and cornering capabilities are greatly improved as well. Although having your suspension revalved by Pro Circuit would make a considerable improvement, the Linkage Arms alone provide a major improvement over the stock set-up. Each link arm includes all of the required bearings and seals.