Terminal Velocity

[gbs]

[maybe the hill you are riding down is just not very steep..??[/quote]

Sorry for not being clear in the OP. 50kph is the conclusion of someone who rides the Alps for a week or so each year where I guess the major Alpine passes average 10% or so.

 

[ColinJ]

Weight is a factor. I regularly overtake other forum members on downhills when I am freewheeling and they are pedalling. That's because I weigh nearly double what some of them do so there is nearly double the force dragging me downhill, but much less than double the wind-resistance holding me back.

I hit 50 mph freewheeling from Blackstone Edge to Littleborough a few months back. I was on the drops and had my head down. but I had a Camelbak bag on my back which would have been producing some extra drag. The slope in question averaged 7.1% for 2.4 km.

 

[ArDee]

On the London to Brighton ride a few years back, on the final hill down into Brighton achieved 83 kph (51.8 mph); braked when I saw an ambulance at the side of the road picking up another rider, I was on the drops on a tourer with mud guards and somebody on a mountain bike overtook me of nobble tyres.
Regularly achieve 65 kph (40.6 mph) on commute to work down hill into Wadesmill from High Cross.