I noticed a new noise on my 2001 R1100S for the first time today. Starting at between 75 and 80 mph I get a high-pitched metallic humming. It goes away if I slow down. It happens at the same speed, regardless of gear, so I don't think it's rpm / engine related. Brake usage has no effect on the noise, so I don't think it's brake related. The ABS is working fine.
It doesn't come on slowly as I accelerate. It's like a light switch. It's no noise, no noise, no noise, then noise. It doesn't happen every time I reach the speed either. Maybe 90% of the time. It does not change in pitch as I change speeds.
Any thoughts? My first thought is wheel bearings. I think I can eliminate the alternator and alternator belt because it's speed-related instead of rpm related. Right? I don't think it's brakes either. Tires are a thought, but the sound is pretty metallic and it doesn't change pitch or volume when I turn the bike.
I plan to pull the wheel this weekend. Will a bad bearing be obvious using the "stick my finger in the hole and turn it" test? I can't say I've ever felt a bad one.
Thanks in advance,