Regarding the possible problem of the bike computer not registering a correct speed when going fast, I wonder if the sensor on the fork might not pick up the magnet passing the sensor if the magnet is passing too quickly. For this reason, I have tried to mount my sensor and magnet as close to the hub as possible. My reasoning is that the closer the magnet is to the centre of the wheel, the slower it will be passing the sensor.
Also (more on the topic of the Rohloff hub), I haven't noticed any drag from the Rohloff while coasting at speed. But then, I don't have any other similar bike to do a comparison. My other bike is a 2002 Cannondale hard-tail mountain bike with an aluminum frame and 2x1.75 commuting tires. It is much lighter than my Nomad. There is a big hill about a km from my house, and on my Cannondale, I once hit 69 km/h. At that speed, I was actually scared, because the bike felt like it was floating. I gently applied the brakes to slow down, and hoped that I didn't need to do an emergency stop. I wouldn't want to go faster than that speed on that bike. After I got my Nomad, I rode down that same hill (on 2x2.00 Duremes), trying to go fast. It was night, so I couldn't read my speed until I got home. On the way down, the bike felt completed balanced and stable, not "floating" at all. I could easily have gone faster, if I had a steeper hill. (I couldn't pedal to go faster, since my 38/16 gearing means my pedalling tops out at 55 km/h.) When I got home, I checked my "maximum speed for trip": 69 km/h. What a difference between the feel of the bikes.
- Dave