So I have my bike about a week and its showing 65miles on it.  Getting real comfy with shifting.  I took it out today and I had to get on a 2 lane highway.  State route 9.  Anyway.. the speed limit was 55 mph.  Well i never gone that fast and i was a bit surprised by the wind factor at that speed.. boggles my mind how people can go 115mph.. My question is what type of posture are you supposed to be in at that speed or higher.  I will in the future venture out into a real highway with 4 lanes and will need to be going between 60 and 70.  Just want to prepare myself for that wind factor effect. 

Am I supposed to keep the same posture as riding around at speed of 30-45 miles? 
Am I suppposed to lean downward more toward the motorcycle gas tank?  I think this is what i ended up doing and my whole back started to ached when i got home.

When Im 80 plus or so I lay on the tank with chin resting on the tank and feet on the rear passenger pegs.  You can really feel the difference from sitting upright with wind resistance, RPM at certain speeds, and mpg. 

Are you dressed properly? While there's some force to the wind when riding upright, it's not all that great, though it may seem so if you have not been riding - or if you are underdressed (aside from protecting you if you end up on asphalt, you should be able to withstand June bugs hitting you at 65MPH...)

As an old creaky person, I don't do the sportbike crouch, but I have no trouble facing into the breeze at 65.

I find that at about 70 mph I start to get beat around pretty good on my naked GS.  Anything below that is not too bad.

Ya know... ive never had any problems with the wind on my naked GS. I tend to keep the same posture for all speeds but if im trying to get a few extra miles (per gallon or per hour) I'll tuck.
if you keep your knees pressed against the tank you shouldnt ever be holding on for dear life by the grips.

BUT there is an EXTREME difference between riding with my mesh jacket and riding with my rain suit or leather. With the mesh i just seem to cut through the air so nicely.

If you dont want wind on your chest than get a windscreen. If you have an F modle tuck below the windscreen and you'll be fine. me I sit which ever is comfy for me at the time whether 60mph or 90mph. But then again I had lower bars than you and higher pegs also so my position is less upright than stock