Stories of FDs failing in the middle of Patagonia, or Tunisia are scary. Typically, the main bearing fails fails in some God-forsaken place, causing the rear wheel to wobble with a near loss of control, the seal is shredded, and gear oil covers the rear wheel. End of vacation/adventure.
I have been wondering why BMW would continue using such a pitiful wheel bearing on most of its line for some 10 or more years. On top of that, there is the obvious feel that BMW holds us in contept for these failures. Well, from my single experience of a FD failure, perhaps I am begining to understand their point of view.
Here is the test that I recommend: lift the back of the bike with your left hand and spin the rear wheel with your right. Mine felt more like a patio screen door, while a good FD feels like a damped refrigerator door. I rode like that for some 1500 miles.
By the time I replaced the bearing, there was still no free play whatsoever. I found some flakes on the magnetic drain plug, a severely pitted section on the outer race, and one pittted ball. I am sure that my FD could have gone for another 1000 miles before being noticeable while riding. My bike had 42,750 miles, and I was using Redline Shockproof Heavy gear oil.
Morale of the story? Check your FD for smoothness and free play every time you wash it. Bearing take a long time to disintegrate. The bearing replacement takes 2-3 hours, and the bearing costs about $110. Steptoe can even do it on the side of the road with basic tools. The only difficulty I had was with the removal of the old bearing: there is not enough room for a normal bearing puller. I used a pair of thick chisels and a mallet, but I think Steptoe can do it with tire irons. (Steptoe, can you tell us how you do it?) One trick Steptoe does give us is that he heats the new bearing on the exhaust so that it drops in without the need of a press.
I chose not to replace anything else because it all looked perfect. The gears and even the seal looked brand new. Here are the pictures of the flakes I found and my failed bearing:
