[darkr]

I regularly exceed 40mph on my road bike, on downhills at least. It's fine.

I'd agree that you shouldn't be in the bike lane at those speeds (though in much of the UK they are few and far between and mostly consist of a bit of paint on the side of the road). That's what roads are for.

[anon4]

40mph? Really? Not 40kph? Because holy fuck -- once I managed to go 50kph for a minute and that's incredibly FAST.

[darkr]

Yeah. I hit 46mph the other week on a long fast descent. That's nothing particularly out of the ordinary; especially compared to pro cyclists - Fabian Cancellara reportedly exceeded 80mph on the Tour de Suisse in 2009.

Here's a fun video of a 2011 TDF descent: https://youtu.be/MSmhgOFGl_M