wheel axle looks bent second opinion wanted !
- Thread starter lgordonhobbs
- Start date
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mickle
innit
- Location
- 53.933606, -1.076131
Absolutely right.
Yellow Saddle
Guru
- Location
- Loch side.
Rear axles don't bend, they crack.
A rear axle on a freewheel hub experiences cyclical stress from pedaling forces. Basically, chain tension comes and goes with pedal strokes and pulls the freewheel and hence, axle, forwards. This constant bending and relaxing induces metal fatigue into the axle. This fatigue has a nice starting point in the valley of the threads. Eventually it becomes brittle and breaks. The break appears as a bend, but it isn't. It is easily demonstrated by blocking one end of the hollow axle and putting that end in a glass of water. Now blow on the other end. Bubbles will emerge from the broken area.
In the old days of hyper light spaceframe racing cars and dune buggies, this "feature" was used as a trick to show cracks in the tubular spaceframe of the car. What they did was to seal the frame off completely and put a air valve in somewhere and a pressure gauge. The frame was then "inflated" and the pressure noted. As soon as the gauge drops, you know there's a crack somewhere and you should stop racing and find it.
A rear axle on a freewheel hub experiences cyclical stress from pedaling forces. Basically, chain tension comes and goes with pedal strokes and pulls the freewheel and hence, axle, forwards. This constant bending and relaxing induces metal fatigue into the axle. This fatigue has a nice starting point in the valley of the threads. Eventually it becomes brittle and breaks. The break appears as a bend, but it isn't. It is easily demonstrated by blocking one end of the hollow axle and putting that end in a glass of water. Now blow on the other end. Bubbles will emerge from the broken area.
In the old days of hyper light spaceframe racing cars and dune buggies, this "feature" was used as a trick to show cracks in the tubular spaceframe of the car. What they did was to seal the frame off completely and put a air valve in somewhere and a pressure gauge. The frame was then "inflated" and the pressure noted. As soon as the gauge drops, you know there's a crack somewhere and you should stop racing and find it.
