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Wheel Stress Testing

In a recent review of our Aero 40 wheelset by, Jim Langley set out ten tests for wheels to pass. In it, he mentioned about stress relief and why he feels that all wheels should be stress relieved at the factory. He mentioned he didn’t know if the wheels, which passed the other tests with flying colors, were stress relieved. We took on board this information, and we bought a new piece of machinery to make sure we do it correctly.

The test criteria

1. Trueness (lateral / side-to-side rim runout)
2. Roundness (vertical / up-and-down rim runout)
3. Rim centering (how well the rim is centered over the axle – so that it is also centered in the bicycle)
4. Spoke length (too short or long usually results in problems down the road)
5. Spoke tension (loose or uneven spoke tension causes wheel problems)
6. Spoke twist (the Aero 40s have bladed spokes, which should not be twisted)
7. Stress relieved? (stress on the spokes, nipples, hubs and rims during wheel building should be relieved)
8. Rim strip fit
9. Tire installation
10. Tire removal

The answers all came back very favorably for our wheels. The only issues were that he didn’t know if our wheels were stress relieved and we’ve now shown that we do this properly. The only other issue was spoke twist, and we’ve also taken steps to fix this issue. We love feedback, and we’ll always work to fix any issues that arise with our products.

What is stress relief in wheels?

There are 2 reasons for relieving stress in wheels. The first is that as spokes are wound into the wheel rim, they can then unwind as you ride. If this happens, your wheels will become untrue and a little less stable. By stress-relieving, we are making sure that your new wheels will stay truer for longer.
The second reason is that by stretching out the spokes, we are making sure that they will not be as quickly stretched due to riding or accident. Again the theory here is to make sure that your wheels stay as true as possible for as long as possible. It will also mean that your wheels may only need a slight true as opposed to a shop having to take them to task to keep them true.

Why we use a stress relief machine?

There is such a thing as too much of a good thing. Being too brutal with your wheels when you are relieving tension can damage them. It may be possible or impossible to see the damage that you cause if you are too heavy with your wheels. So, we use a machine to make sure that our wheels are subjected to just the right amount of force. Enough to make sure that all the spokes are bedded in and not too much to damage the wheel.
The other great thing about the machine is that it allows all of the spokes in your wheel to bent into shape. This is a common practice amongst material scientists. If a piece of metal is just manufactured into exactly into the correct shape, it will generally have some trapped stress. By stress-relieving, we are pulling the spokes into the correct shape, and removing the pent up stress. The process then should bring you longer lasting spokes.

  • Oct 18, 2019
  • Category: Articles
  • Comments: 0