i also have a hard time believing those that say they're getting 30+ out of the 2.8 (unless they are on a long, slight decline). the math shows the number you can get. weight and drag aren't factored into those so you will generally see less, unless the bike has the power to do it. i was running 43mph with 12/70 gearing on the stock tire. this was with a modded 6.5 (around 11-12hp). that was spinning a bit over 6,000rpm and i was really pushing it. in my situation, i just didn't have enough gear because it would get up there quick.