You learn something new everyday. I have been using the Roomba for the past 5 years at least without realizing that the front wheel needed cleaning. I clean the side wheels and the brushes religiously, occasionally using the air compressor, but front wheel, nah. That's until one of the Roombas started making a funny noise. When it runs, it would sound like it's going over a hump every second. I have heard that before when the bottom brushes are not properly fitted, but this time the problem is not that. I finally traced it down to the front wheel. I noticed it does have quite a bit of hair stuck in the axle. After struggling on my own for awhile to figure out how to clean the damn thing properly, I turned to YouTube: Turned out it was pretty easy. You just pull the wheel carrier right off with a bit of force, then pop the wheel off with a flat blade screwdriver. Then I found the culprit: It's a tiny bead from my daughter's DIY necklace toy set,...