TransAm
Well-Known Member
I found a stress/fatigue crack in the frame of my 2020 V20 w/4000mi on it:
This is in the upper seat-stay attachment to the hydroformed tube (note the rear brake adjuster in the corner of the image). It is a longitudinal crack in the base metal at the toe of the fillet weld. It has propagated all the way around one side of the weld. I assume the crack initiated at a stress point and has been growing in the heat-affected zone ever since. I understand this can happen when the base metal is not sufficiently pre-heated before welding, and/or the weld is allowed to cool too quickly afterward.
I had noticed a creaking sound on the last few rides, but thought it was in the seat. I installed the new adjustable seat, but the creaking persisted. I found the crack when I turned the bike upside-down--it's not noticeable when the bike is upright. I don't know how long the crack has been propagating, but it could be an extended time period, because I have not been looking at this area. The crack is open enough now to catch a fingernail.
I have not had any major/injury crashes with the bike, and the frame has no crash damage. But this is my first recumbent bike, so I have had several low-speed tip-overs when I could not get a foot down quickly enough.
I just found the problem today, so I have not been in contact with CruzBike to see what my options are. I'm posting this to let V20 owners know this is a possible failure mode, and to be on the lookout for it in case other frames have the same issue.
This is in the upper seat-stay attachment to the hydroformed tube (note the rear brake adjuster in the corner of the image). It is a longitudinal crack in the base metal at the toe of the fillet weld. It has propagated all the way around one side of the weld. I assume the crack initiated at a stress point and has been growing in the heat-affected zone ever since. I understand this can happen when the base metal is not sufficiently pre-heated before welding, and/or the weld is allowed to cool too quickly afterward.
I had noticed a creaking sound on the last few rides, but thought it was in the seat. I installed the new adjustable seat, but the creaking persisted. I found the crack when I turned the bike upside-down--it's not noticeable when the bike is upright. I don't know how long the crack has been propagating, but it could be an extended time period, because I have not been looking at this area. The crack is open enough now to catch a fingernail.
I have not had any major/injury crashes with the bike, and the frame has no crash damage. But this is my first recumbent bike, so I have had several low-speed tip-overs when I could not get a foot down quickly enough.
I just found the problem today, so I have not been in contact with CruzBike to see what my options are. I'm posting this to let V20 owners know this is a possible failure mode, and to be on the lookout for it in case other frames have the same issue.
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