The Vitra Eames Aluminium Chairs are tested to 110 kg. If the user is heavier, the chair can still be used but the wear increases. Not only the user's weight plays a major role in the durability of the chair, but also the users habits. If, for example, you regularly "drop" into the chair or used the armrests to help you get out of the chair, localised stress peaks can occur which can be greater than the burden of a "static" very heavy user.