Does anyone have a problem with their kneecaps not tracking properly and have found a knee support that helps, and can be worn comfortably whilst cycling?
It seems to me there are many possible causes of this. I'm simply a cyclist but my experience is that until you identify the cause the best self-medication can achieve is to mask or relieve the symptoms. Like
@ColinJ I have one leg, by 5mm, longer than the other. This has never been described as "significant" is your variation greater Colin? I was in my 60s before this was diagnosed.
By chance a podiatrist with specialities in gait analysis and skeletal bio-mechanics joined my club. We got to know each other well, one day she asked "You know you pronate?" I'll cut a long story short but after addressing the leg length issue other issues became apparent. Over a two year period each problem was relieved and all the discomfort I experienced was relieved.
Imagine 60+ years of compensating for different leg lengths and the damage this causes. I now understand how this impacts on the whole leg from the sole of the foot up to the hip. Correctly positioned but simple raisers in my shoes have resolved all the issues. Correcting leg length is easy, correctly positioning the foot afterwards less so.
One consequence was to dramatically change my bike position and overall fit. Unknowingly throughout my cycling life my set up was very wrong as it was a compromise for my differing leg lengths. The bike position change was NOT the solution it was a consequence of identifying and fixing the underlying problem, the cause.
With respect to other posters I feel a bike fitter might offer a solution, a physio treat any symptoms but neither will necessarily identify the issue. I can't say a podiatrist will but I do feel the OP should consider his knee tracking problem may be a consequence of another underlying issue.
Colin I suggest if your leg length difference is "significantly longer" you need to speak to a good podiatrist.
@travellingwest try Googling "knee tracking cycling issues" this could help you consider your direction. I'm not suggesting you have any particular issue but that you must identify the underlying problem rather than simply mask the symptoms.