Multiple Spoke Fragmentation

by Andrew Ruscoe 24th May 2008

In January this year (2008) I made a complaint to ****** about the quality of some bicycles I purchased late in 2005. My complaint was that the wheels (specifically, the stainless steel spokes) should not have failed after such a short time and in such a dangerous way (particularly given such light use). Several spokes failed simultaneously on my daughter’s bike in November 2007. The rear wheel buckled as a result and could no longer rotate. The spoke failure appeared to be due to a manufacturing flaw. I complained to ****** on the basis that this particular manufacturing flaw in the spokes poses a safety hazard to the community as a wheel can fail to the point of seizing at any time without warning. This is what happened to my daughter’s bike. Fortunately for us, we weren’t in traffic, we were going slowly, and we were close to home.

Figure 1: Corrosion visible in broken “stainless steel” spokes

Over the course of my inquiries I have received several statements confirming this fault to be a manufacturing flaw in the stainless steel spokes. It seems these flawed spokes were used in bicycles made by many different manufacturers in the years 2005 and 2006. I gained this information from talking to bike shop personnel and the following sources. A representative for ****** wrote, "Information that has been received from numerous specialist bike shops indicates that there has been an issue with spokes breaking in the industry which is related to a lack of Chromium 6 in the metal. This has affected bikes right across the industry from cheaper brands to expensive brands." A representative of ****** wrote, “the issue of premature spoke breakage on bicycle wheel is well known to us. Spokes, which were supposedly stainless steel, had been made with faulty material resulting in these spokes breaking early in their life. This affected many new bicycles up to 2006 models and bicycle distributors were involved in replacing or repairing a large number of wheels.” Although ****** and ****** have known about this problem since before I experienced it, they believe that this flaw does not pose a significant threat to safety.

After further correspondence between myself and ****** over a number of months they requested a sample of the spokes which I supplied to them early in May. I do not know why they are testing them when the problem is known to them and industry. I do not know why they are only testing 2 spokes out of the 36 that are on a wheel.

I describe this problem as multiple spoke fragmentation. The manufacturing flaw appears to be that the spokes (which are supposed to be stainless steel) corrode internally at points along its length. Corrosion is not visible on the outside of the spoke but can be observed looking end on at a broken spoke (see Figure1). This hidden corrosion is dangerous because a weakened spoke looks to be in good condition. This corrosion seems to require no special circumstances. Some people’s spokes are breaking while their bikes are in storage. The weak points along the spoke allow it to be broken easily into fragments (see Figure 2 & attached video files). I have found that corrosion has become visible on the outside of spokes some months after some of them have failed.

Figure 2: Spokes break easily into short fragments.

My aims in writing this article are:

1. I would like to raise public awareness of the problem. Stainless steel spokes should be carefully inspected before riding. Particular attention should be paid to bikes purchased in 2005 & 2006. Owners of bikes purchased during this time period may like to discuss the likelihood of this problem occurring on their bikes with the place of purchase.

2. I would like to gain feedback from people who have had similar problems with spokes.

3. I would like to encourage people who have had this problem to lodge a complaint with their state’s government department for consumer protection. When I have raised this issue with ****** they say that no one else in Australia has complained about it, so (in their view) it can’t be much of a problem.

Please contact me, Andrew Ruscoe, at spoke_fragmentation@hotmail.com.