Bicycle Mechanics - Shimano Dura-ace rim crack questions!

Was washing my bike yesterday and replacing a worn tire and noticed 2 cracks in my DA rear rim. This is only my second season on the wheels, probably 4000 miles on them.

The 2 cracks are on one side of the rim, parallel to the arc of the rim, maybe 1/8th on an inch below where the spoke enters the rim. Larger crack is maybe an inch long.

1) Will this likely be replaced under warranty?

2) Is this typical for lightweight rims? I really don't want to be going through this every 1-2 years. I am 6'2" 195, not the lightest rider out there, but no clydesdale by any measure.

Was washing my bike yesterday and replacing a worn tire and noticed 2 cracks in my DA rear rim. This is only my second season on the wheels, probably 4000 miles on them.

The 2 cracks are on one side of the rim, parallel to the arc of the rim, maybe 1/8th on an inch below where the spoke enters the rim. Larger crack is maybe an inch long.

1) Will this likely be replaced under warranty?

2) Is this typical for lightweight rims? I really don't want to be going through this every 1-2 years. I am 6'2" 195, not the lightest rider out there, but no clydesdale by any measure.

I am surprised to hear that - they are supposed to be rather resilient wheels. I have been running my Dura-ace wheelset for just under 6000 miles, but I weigh 43 pounds less than you do, and I guess when I hit a small pot hole, it does not cause the same stress that it would if you hit the same thing. Let me know what happens vis-a-vis the warranty, but I would assume the only way you could sustain a warranty replacement would be with evidence that the wheel simply failed without something unusual happening to it. It will be interesting to see what Shimano's attitude towards customer service is.

It really looks like the failure is one related to spoke tension, but I am no expert. Other than these cracks, the rim looks as good as new.

It really looks like the failure is one related to spoke tension, but I am no expert. Other than these cracks, the rim looks as good as new.

Did the wheelset come with your bike, and if "yes" was it tuned at the LBS? If you had a spoke tension discrepancy I would think it would have shown up as the wheel being out of true.

No - I bought the DA wheels last year from Performance along with the DA10 grupppo. Wheel was not out of true last time I checked.

No - I bought the DA wheels last year from Performance along with the DA10 grupppo. Wheel was not out of true last time I checked.

If it was not out of true, then the spokes must have been fine. I am amazed the abuse these wheels take without going out of true. I ride on some rough streets.

Most rim failures are caused by rough roads not spoke tension, at least that's what Jobst Brandt says.

Al