Shimming A Faith Forgotten Choppers Springer
Article And Photos By: Will Ramsey – faithforgottenchoppers.com
Originally Published In The May 2019 Issue of Cycle Source Magazine
Springers often get a bad rap due to handling issues. Sometimes this is due to poor geometry in the design that creates excessive trail (either negative or positive), and sometimes it is due to a poor spring rate that is inappropriate for the weight of the bike. But quite often, the handling issues can be traced to the rockers. If you’ve ever sat on a bike with a springer and noticed that you can turn the handlebars a few degrees right or left without the tire actually moving, then you’ve seen this problem. Believe me, it’s more common than you would think. In order for the rockers to work properly they must be allowed to articulate on the 4 pivot shafts that connect them to the springer legs. In cheap springers these shafts are simply threaded bolts, which will not hold up for any amount of real riding time. Well designed springers use some sort of a ground shaft against a bearing surface. At Faith Forgotten Choppers, we use 316 Stainless Steel shoulder bolts. When fitted to a bushing with a bearing fit there is no concern about rotational slop in the system. However, if not shimmed properly there can still be lateral play. Shimming has to be done during final assembly and if done precisely, it is rarely ever the same as chrome and powder coating finishes can vary in thickness.
During final assembly, the Rockers are the last component to be fitted and torqued. The assortment of stainless-steel shims are designed to lengthen the shoulder bolt. The goal is to achieve full torque without binding the rockers or allowing any endplay.
The shoulder bolts that we use are polished 316 Stainless Steel. This follows the entire design of a Faith Forgotten Springer, in that there are no plated fasteners. Chrome fasteners have a nasty habit of rusting after being torqued by a wrench.
The head of the shoulder bolt is spaced from the rocker by an iron impregnated oil lite thrust washer. Since the rocker is moving, the joint between the head of the bolt and the rocker is a wear point and can gaul if not separated by a bearing surface.
The joint between the rocker and the leg is spaced by the flange of the oil lite bushing that captures the shoulder bolt.
This picture illustrates the assembly of the rocker to the two corresponding shafts and oil lite bushings.
Before the assembly can be fitted, the springer legs must be reamed to remove chrome or powder. In this case a clear powder coat is being removed by the 5/8” hand reamer.
Once in place, the lengthening shims can be added. This is a trial and error process and must be done on each of the four pivot points.
In most cases it is necessary to stack a couple shims to get a precise fit. This is just a matter of patience and care.
I simply use a hardware store nut to bottom out the nut against the shoulder bolt as I will most likely have to remove it two or three times to get the correct fit with the shims. Once the shims are determined a final torque is made with one of our polished lock nuts.
If the fit is correct, I should be able to rotate the shoulder bolt with slight friction. This indicates that the rocker is not bound, and that no endplay exists in the joint
With everything assembled and torque our final product is a reliable American made springer that responds and handles to every movement of the rider.