Educate me.

My owners manual for the 07 SD says 4.9 gallon tank, with .9 gallon reserve. I take that to mean 4 gallons usable fuel. Figuring a conservative 35 to 40 MPG, this bike should get 140 to 160 miles before hitting reserve. Yet I read online guys are getting 80 to 100 miles before reserve. What gives?

I do understand that different riders get different economy depending on how they ride the bike, but 80 miles a tank seems ridiculous.

I get around 130 miles before my light comes on. Sometimes a little more, sometimes a little less.

I can safely say that I can go 150 miles between fill ups. Some slabbing and some blasting...