Shock mount failure

[Don Bradner]

Did your tear look at all like mine (mine looks almost exactly like Pete's)?
Presumption is that the slamming downward when the wheel bottoms into a pothole
or similar is the issue. Countless slams, and the metal gives way. Note that it
is not the frame, but rather the steel mounted to the frame - that steel is a
part of the axle assembly and was presumably not welded by BB.

The repair done on mine comes close to matching the original assembly, making it
possible/likely that sometime in the next 20 years it will fail again. I'm going
to try to remember to stick a camera in there for photos every few months (more
often to begin with!) that it is driven.

On 3/10/2009 at 2:22 AM Eric Perplies wrote:

>My front left shock mount broke just before the Q rally in 08. CCW in
>Riverside fixed mine shortly after the Q rally. On my coach the shock
>mount ripped out a chunk of metal on the frame. A piece of steel about
>1/2" x 8" x 6" was welded onto my frame. A hole was drilled in it to
>accommodate the brake air line. The original shock mount with it's three
>gussets were removed from the broken out piece. That original shock mount
>was then welded back onto the 1/2" plate mentioned above.
>
>The welds made during the repair were VERY thorough. There was an
>indication that the original BB welds may not have been as through as they
>could have been. (One side of one of the gussets had not been welded onto
>the frame.) That having been said this could not be the reason for the
>failure. After all the frame on my coach had a section ripped out of it.
>The shock mount itself did not fail.
>
>A far more interesting question is: What causes the failures on the shock
>mounts?