Hi,

I recently had some samples made in Asia and they performed the ISO4210 test.
During the test the downtube broke. (at the end of the test)

The downtube is an Chromo 34.9 mm ovalised to 40x30 mm (40 mm wide).
We normally use a double butted tube (0.9-0.6-0.9) in our bikes but because of ovalising problems due to lack of a mould, a tube with a wall thickness of 1.0 was used (not butted)

How is it possible that this tube broke. It's quite an heavy downtube.
(We have never performed the test with the double butted downtube.)

Thanks,

Marc