I thought that everyone selling bike parts has to adhere to the ISO4210 testing protocol anyway as it is obligatory in most countries. Maybe someone with more background knowledge in the world of engineering and standards can explain better.
But what that means is that fatigue testing of sample frames doesn’t really set Chinese frames apart from the big brands. It is the level of QC (or its existence in the first place) that makes the difference. Right? What good is fatigue testing of one sample frame if they then crank out thousands of these frames without ever looking at any of them before they get shipped?
Maybe I could share some more on this topic.
For a bike manufacturer, no matter legit or fake, they got all sort of QC failed frames, but those that really are unsafe to ride, usually will be disposed and will not be sold, simply because it could lead to fatal accident, no one wants to risk that, even for a factory that makes replica.
Then, this part people probably would be more familar, the rest of the products would go into different class, Class A, B, C etc.
A could be the best product, such as perfect paint, alignments etc..
B could be less than ideal, some minor issues.
C could be merely acceptable, maybe some alignments are off, but still won't give you too much trouble building that bike and you could still ride safely.
Here's the thing, those you bought from legit brands, most of the time they are Class A (please note "most of the time"), you are paying big money for the best products after all.
Then where did those from Class B & C go? No way in hell they are disposing them because there are a lot of money involved in making them, they might be secertly sold to different retailers, usually to those not so well-known retailers, or they might just sell them themselves, get a promotion going and sell them with a discounted price.
There are a lot of retailers out there, some constantly bought Class B product and sell as cheap frames, some bought Class C and sell even cheaper, that's just how it works. Some evil retailers exist, they might somehow got their hands on those disposed failed frames, and sell them with a dirt cheap price. That's the reason why I would stay away from those $200 USD carbon frames. It is difficult for a factory to get away if the frame eventually breaks, but a lot easier for a retailer.