Rushmore bikes may be exempt from horror stories like The Harley Wobble but the rigidity of their swing arm still depends on rubber mounts and bushings. Based on this perspective, I decided to try The Alloy Art Frame Stabilizer on my 2015 Road King because towards 40K km (25K miles), the bike started to feel a bit less stable than when it was new. Unless the pavement was silk smooth, the curves became a bit less confidence inspiring, despite wheel alignment, suspension settings, tire pressures, triple tree bearings, etc., all being as they should be. No rubber mount or bushing was defective (but they may have softened up a bit during the miles).

Installation was easy but the instructions sheet was an extremely poor photocopy with terribly blurred pictures. Fortunately, the design is simple. What is what and what goes where do not require a degree in rocket science. I had to perform some simple Dremel work on my right side heat deflector but I did not have to remove my H-D brand heat deflectors for good.

Unlike the instructions sheet which is not up to the standards of any self-respecting business; the design, materials and workmanship are top notch. Every component is perfectly machined and carefully finished. Longer bolts are supplied to compensate for the thickness of the support plate. What impressed me most is the angle of the rod that connects the starter to the frame. It remains parallel to the width of the frame. That is; perpendicular to the vector of the forces that it counters. This position has a great multiplier effect to the strength of the already beefy rod.

The instructions do not call for installing the stabilizer when the bike is upright but IMO, this must be the case. When the bike is on the jiffy stand, the heavy engine/transmission assembly must be compressing the rubber mounts on the left. I lifted the bike before aligning the rod, in order to be certain that the engine/transmission assembly is in its neutral position.

The alignment process is to be performed only once, for good. The stabilizer is not an alignment tool to alter the position of the engine/transmission assembly relative to the frame. It is for keeping this assembly in its neutral position against the forces that try to shift it. Therefore, the adjustable rod does not have left-hand threads in one end. That is; it cannot be adjusted when both ends are connected. IMO, this serves the purpose better than an adjustable turnbuckle because one needs to feel the ease at which the bolts pass through the holes. Locking nuts at both ends secure the length of the rod, as well as the position of the joints relative to the rod for good. No further adjustment will be needed, unless some rubber mounts/bushings are replaced.

With the stabilizer installed, the 103 idles as if it had a tranquilizer pill. I may say that it does not shake vigorously at idle but it still vibrates proudly. I don’t know where the surplus between “vigorous shake” and “proud vibration” goes but I feel that it does not reach the handlebar. I surmise that the rubber mounts/bushings may now be forced to further dampen the shaking forces.

At speed, my Road King is more stable in curves, significantly more so in bumpy curves and on irregular pavement. To give you an idea on how much more planted my bike now feels; I had a similar sensation of “sure footedness” when I had replaced my stock shocks with Progressive 444s. I conclude that improving the rigidity of the swing arm pays dividends and this is exactly what frame stabilizer kits do. They reduce the movements of the engine/transmission assembly relative to the frame. Since the swing arm is connected to the engine/transmission assembly, flex in this area is mitigated. I do not mean that this mitigation transforms a Harley to a super sport bike but it surely makes the behemoth feel better planted and more agile. I recommend the Alloy Art Frame Stabilizer to those who are looking for a way to improve the stability of their Rushmore bikes.

Nice piece and well built, install about 25 mins.
Rode a few times the motor didn't shake thst muck.