Free electricity for Christmas?

[Andrew Gabriel]

I'm miles off being a top cyclist, actually I'm quite out of shape at the moment, not having done much this summer so far, and nothing last summer.

Tried on an exercise bike last night and this morning... I can do 80W very comfortably for 30 minutes[1], and could probably do at least a couple of hours without difficulty at that rate. I can do 120W for 30 minutes[2], but probably couldn't keep it up more than that without a long break, although a fan would have helped. I can do a short burst of sprinting at 700W (could probably go a bit higher but the artificial wheel resistance doesn't go high enough).

So, where's the F.I.T. scheme for exercise bikes? ;-)

[1] equivalent to a Penguin biscuit. [2] equivalent to a Mars bar.

[PeterC]

In the TdF, even over undulating terrain, they'll do ~25mph for 5h+.

Most are 3W; some are 5W. I don't know about modern hub dynamos - mostly 5W I think.

[Alan Braggins]

Almost all are nominally 2.4W for front light only, or 3W for front and rear, but the hub dynamos are actually roughly constant current devices which will deliver 6W at reasonable cycling speeds if you give them twice the load.

are secondary dynamo lights designed to be switched in at speed (with the switch shorting across them when not used), but there's less point with modern LED lights.

[Alan Braggins]

It was relevent to TNP's "A TOP cyclist".

[PeterC]

All of mine are 3W, usually run as 2.4W and O.6W, and most are modded systems to have LED rear and 3W front.

My only hub dynamo was a Sturmey-Archer, built back-to-back with a hub brake and with a Campag. rear QR axle all in the front wheel of a trike. Bloody good light front and rear! Modern hub dynos are much better. My Father had a Miller 12V dynamo on his tandem in the late '30s - cars used to pull in and stop as their headlights just weren't competitive!

[george [dicegeorge]]