If the tension in a spoke drops to zero, the nipple is free to turn, allowing the wheel to go out of true.

This matters because it implies something important about building wheels: high tension is good. A few minutes with a spoke tensiometer reveals that they don't change, but in fact the tension in the lower spokes reduces. If that was how wheels worked, then the upper spokes in a loaded wheel would have higher tension than when not loaded.

It says: 'when you sit on the bike, the axle pulls down on the rim and acts like an arch … you are, in effect, hanging off the rim of the wheel.'Įxcept you're not. Rider skill, the article concludes, is what keeps a bike upright, which would be fine if it weren't for the fact that you can push a riderless bike off down a slope and above a certain speed it will keep going.Īs well as failing to explain what keeps a moving bike upright, the Beeb repeats common misconception about wheels. It cites Dr Hugh Hunt from the University of Cambridge, as having built bikes with extra, contra-rotating wheels cancelling out the gyro effect of the wheels on the ground.

But unfortunately the article doesn't get even close to answering it, and makes at least one serious error while failing to reach that destination.Īfter quite a lot of waffle about the gyroscopic effect of a spinning wheel, the piece concludes that this isn't actually what keeps a bike upright as it rolls along. With bikes in the news after Channel 5's portrayal of us cyclists as lawless killers, the BBC has gone after a bit of cycling-related website traffic with an article that asks the question 'How does a bike stay upright?'

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