Bike Fit Leg Length Discrepancy

In many a bike fit leg length discrepancy comes up.https://youtu.be/ahkIEHe-HAE1. I always question by what method was it determined that you have a 13 mm LLD? The ONLY way to get an accurate measurement is through the radiology department and have it measured directly from the scanograms. No one can measure the bony landmarks through the skin and soft tissue with any serious degree of accuracy. So I wouldn't necessarily worry about the actual amount of the LLD.2. The goal is never to try to correct the full amount of the LLD (especially when the accuracy of the measurement is in question). If you can correct 30-50% of the difference then you're probably going to be doing well -- over-correcting can be significant;y more dangerous than not correcting at all.3. Are you sure that it's a problem (or that it's causing a problem) on the bike? Many LLDs are muted or absorbed on the bike because we have so many ways to dissipate their effect due to the fact that we have so many points of contact. There's a reasonable chance your LLD might not be as big a problem as you think, so I would investigate further into what specific bike fit deviations you have on the bike (start with the basics -- check saddle height, see how the ankle is moving through the pedal stroke, is your saddle far back enough behind your feet so that you have the right balance?, and is the reach to the bars allowing your pelvis to remain balanced and neutral on the seat or is it drawing you forward?) It's true that shimming toom much under a cleat can cause trouble if it gets excessive -- the further you displace the bottom of the foot from the center of the pedal axle the more instability you can breed through that foot/ankle. But a couple millimeters is probably not going to upset things drastically. Keep in mind that many early road and mountain bike shoes had very think soles on them before they improved the materials to allow for thinner stiffer soles. These were orders of magnitude thicker what you would add through a shim under your cleat. I wouldn't blink an eye at using one of the 3 mm shims that I have at my disposal for this.