If you have never had a bigger motorcycle you might think this is alright for freeway I have a Suzuki LC 1500 you can go down the freeway 80 mph one hand and smoke a cigarette,I live 1/3 mile from a un busy freeway I've put a total of 5 miles on that freeway the other 2000 miles on back roads,I had a 6 cylinder Goldwing before the 1500 suzuki,So I'm uses to big motorcycles.

I have an almost 6 mile stretch of interstate on the daily commute where it's marked 55 and 65 and the traffic typically moves at 70+.

Prior to adding the windscreen, 70 was work since spent most of my time working at holding on.  After the 'screen, the S40 will run 75 and still has about 1/5 throttle left.

I've only tried it once, but I did have it up to 90 indicated before I backed off.  Too many "I'm getting off at this exit from the high speed lane" drivers to keep going that fast.

   Its not underpowered just under weight and to much rpm for freeway driving

I have ran my stock s40 up to 92mph on the highway here in Atlanta with no problems. The speed limit is posted at 55-65 but everyone drives 70 minimum and I have no trouble keeping up with traffic. I guess to each is own. For me the little thumper that could......should.

Interesting that this thread should pop up now. I just walked back in from a lunch run where I ran a few miles on the interstate.  This is not common for me as I usually stick to smaller highways simply because they are more fun.  I hit 75 with no trouble (same vibration at 60 that most experience) and my only two issues were; 1. passing big rigs at that speed was pushing my bike to the limit due to the wind resistance from the front of the rig and 2. it was a very windy day in general so a headwind at 75 pretty much kept me from going much faster.  I did have a little throttle left though but at that speed it just sounds like I am pushing the bike too close to the edge of its comfort zone.

  I only weight 165 I have no problem doing 85 mph

I just got back yesterday from a 1200 mile round trip to the Oregon coast. 65-75 all day long, with no problem from the vibration. However, the seat needs a little more work, and I'm probably going to add some highway pegs.

Most of my riding is on the freeway, at about 60 -65 mph indicated. My '08 has no trouble. I've had bigger bikes, even a Goldwing in the mix. This bike could stand to be a bit heavier, but will do the freeways and highways just fine. I pass semi's and every other thing as need arises. To date, I've had no problem getting the job done with throttle to spare.