How does the plugin work out my side LED count?

Two numbers describe your device on LED Devices > RPM Telemetry > Configuration, and the plugin sets both for you when you install the RPM profile.

Number of centre LEDs is the rev bar itself, the long run in the middle, so 10 for a device laid out 3-10-3. The car's shift points are fitted to whatever you set, which is why one RPM profile now covers every device instead of a separate file per layout.

Number of side LEDs (per side) is the LEDs either side of that centre, so 3 for the same device. It carries the flags, spotter, brake pressure, pit lane, ERS and low fuel.

Only one number ever fits:

strip total = (2 x side) + centre

Your hardware fixes the total, so once the centre is set the sides are whatever is left over, halved. That is why the side slider is usually greyed out: there is nothing left to decide, and a slider you could drag would look like it worked and then quietly revert. The line underneath shows the sum for that device.

To change how the bar is split, change the centre width. On a 16 LED strip a centre of 10 leaves 3 either side, and a centre of 8 leaves 4. There is no file to reinstall.

Every device keeps its own pair of numbers. A wheel and a DDU of different shapes no longer compete, and the plugin handles up to 16 devices.

The side slider stays live only where nothing can be worked out, such as a device that reports no LED total. If you are entering it yourself, count one side, not both, and leave the centre out. A side split into more than one run is still one side, so a 9/3/10/3/9 wheel is 12 per side.

If a device has no side LEDs at all, the plugin says "No side LEDs configured" against the settings that depend on them. That is expected rather than a fault.

If your rev lights fill from the wrong end, turn on Reverse strip under How this strip is wired. The whole strip is read the other way round, so the effects on the sides swap over with it. That is a wiring difference, not a count problem, and no number needs changing.

If it looks wrong on track, the symptom names the fault. The left side correct, the rev bar spilling into the right side and the right side effects sitting too far along, means the centre width is too wide for that strip. Lower it. Both sides wrong means the side count itself is wrong.