I recently had the opportunity to test the reserve capacity on my R1200GSA. The reserve light comes on when I have about 35 to 40 miles range remaining. On my last ride I got down to 0 miles range remaining (display shows "Range --") and still couldn't find a gas station. I ended up going about another 10 miles and when I filled the tank I put 7.6 gallons in it (which meant that I had .3 gallons left in the tank). Total miles on the tank was 283 miles which means I got 37.2 mpg on the tank. Most of the driving was on a turnpike at 80-85 mph, except for the last 35 miles which was on side roads at anywhere from 15-55 mph (in driving rain).
You can read about it in my ride report https://forum.ironbutt.org/index.ph...-and-some-ill-advised-racing.3342/#post-45812
You can read about it in my ride report https://forum.ironbutt.org/index.ph...-and-some-ill-advised-racing.3342/#post-45812