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On Saturday, while ice racing, the rear wheel assembly tore off of the beam arm of my Festiva, where it is bolted to the beam arm. The results were a bit exciting, ending in a snow bank.
Inspection showed one lower bolt sheared, and the other lower bolt, nut and all, pulled straight through the nearly 1/4" thick steel plate in the control arm that it is bolted to, leaving an exploded cauliflower of steel on the arm. The upper two bolts go into a thinner plate that is mounted just above the main body of the beam arm, which has a variety of welded buttresses on it to give it strength. That whole upper tab simply ripped off.
Anyone who runs these cars on the track with upgraded suspensions ever seen a failure of this type?
At first, I thought the bolt sheared first, but once I realized how thick the steel is where the lower two bolts are used, I have to conclude the upper plate gave way first, allowing it to rock enough to apply the force that pulled a nut through 1/4" steel and shear the other bolt. That seems to point to metal fatigue, does it not? As someone pointed out to me, there is almost no weight on the back end of the car. But one does spend a lot of time sliding the rear end sideways when ice racing.
Inspection showed one lower bolt sheared, and the other lower bolt, nut and all, pulled straight through the nearly 1/4" thick steel plate in the control arm that it is bolted to, leaving an exploded cauliflower of steel on the arm. The upper two bolts go into a thinner plate that is mounted just above the main body of the beam arm, which has a variety of welded buttresses on it to give it strength. That whole upper tab simply ripped off.
Anyone who runs these cars on the track with upgraded suspensions ever seen a failure of this type?
At first, I thought the bolt sheared first, but once I realized how thick the steel is where the lower two bolts are used, I have to conclude the upper plate gave way first, allowing it to rock enough to apply the force that pulled a nut through 1/4" steel and shear the other bolt. That seems to point to metal fatigue, does it not? As someone pointed out to me, there is almost no weight on the back end of the car. But one does spend a lot of time sliding the rear end sideways when ice racing.
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