n2t, I run it at 25 mph on the flats and max out at 31.6 mph. If you guys want more speed. Then look at replacing the cassette (rear gears). Some of the bike racers are using the 48/38 front gears but have a 11/25 cassette. The Denali has a 14, 16, 18, 20, 22, 24, 28 cassette. Racers try to keep between 90 to 110 cadence. So with all that in mind, here is the top speeds at a 100 cadence.

With a 48 x 14 you get a max speed of 27.30 mph.
With a 52 x 14 you get a top speed of 29.58 mph.
With a 48 x 11 you get a top speed of 34.75 mph.
With a 52 x 11 you max speed would be 37.64 mph.
The speeds stated here are all figured at 100 cadence.

Now if you do change out the Cassette for a 11/25 then remember that it will be like start out in 2nd gear.

But then again a average commuter will all most never use below a 17 or 18 tooth rear gear. Which I can run the 48/18 (5th gear) at 23.36 mph at 110 cadence. See I call the Denali a 7 speed bike because I almost never use the middle chainrings. And never use the small chainring. I'm looking into changing the crankset for a 52/42 crankset. How ever, you guys that don't live in the flat land of Florida may need the lower gears for hills.

Hope this helps.