My 78 BMW R100S hack torched it's front wheel bearings a few weeks ago. I had noticed the front end intermittently diving, as if I had applied the front brakes hard on and off, while cruising at any speed. Then one day, I was approaching my street, started to slow down, heard a metallic grinding noise, came around the corner, and the entire bike nose dived to a sreeching hault. I let the bike cool down for a few minutes, then rocked it back and forth and freed up the wheel - rode it home 1 block without using the front brakes and parked it in the garage. I initially thought my calipers had locked up and had them rebuilt. Re-installed them, bled the brakes (for 2 hours!) and went for a test drive. All seemed fine until about 10 minutes down the road when I started hearing that metallic grinding/crunching noise again and the nose started to pop up and down. I immediately pulled over just in time (was doing 50mph at the time) just before the front wheel locked up. Was able to rock the bike back and forth to free up the wheel and then limped home at 10 mph, stopping a few times to unlock the wheel.
Turned out the wheel bearings were totally torched, disintegrated and fused themselves to the axle. Had to cut the axle to get the wheel off, in the process of taking out the axle I accidentally cracked the fork lower, but thats a another long story and $600 mistake I made ; {
My BMW mechanic put it all back together, new axle, bearings, spacers, oil seals, etc.. Had to add some pretty large shims to get the wheel to spin free at the BMW axle bolt spec torque of 36 foot pounds to keep any pre-load off of the new bearings. The ride home was nerve racking as I listened for any hint of metallic grinding noises. I thought I did hear a crunch or 2 on the ride home, no nose dives, but it could be I am a little apprehensive because of my past experience with the wheel lock up. I called the mechanic and told him I thought I heard a grinding noise/pop but it was possible it could have been a rock running through the front fender. I did heard a ping type of noise after I turned off the bike in my garage - that sort of tinging noise you hear when a hot motor cools down, but it seemed to come from the front. I sat next to the wheel for a few minutes to see if the noise would reappear, but nothing. I jacked up the bike so the front wheel was off the ground and gave her a spin. It did spin mostly free, just some noise which I am pretty sure was the brake pads. I wiggled the wheel and it seemed tight, and spun it again, this time it seemed to spin more freely. I can't imagine that wheel bearings would torch so quickly (only 40 miles or so). My mechanic did mention that he needed to use some red locktite on the bearing that sits against the "race" on the wheel because it didn't seem to want to stay put. It did bottom out, so he didn't think the wheel was toasted, but he did need to use some locktite. He didn't believe that locktite would break loose, but if I had bearing issues again, he thinks I will need to replace the wheel and start over. He also believes my apprehension and concern about the bearings is making me believe I am hearing things and that I should not worry but just ride it and have fun.
Has anybody else had wheel bearing issues like this? Do sidecars add a significant amount of stress on the front wheel that bearings wear out quickly?
Thanx.
