Abstract: A method of installing or adjusting belt weighing machines to reduce errors in the weights recorded applies to machines having a conveyor belt (25) which is driven over a series of idler rollers (22, 24, 23) in which one or more idler rollers (24) are supported by a weight sensing system. In a first adjustment the isolation of the weighlength is improved in a static test by altering the separation between the first threshold idler roller (A, A') and either the adjacent non-weighed idler roller (B, B') or the next but one weighed idler roller (D, D'). In a second adjustment the theoretical weighlength is adjusted by moving the first threshold idler rollers (A, A') to compensate for the disparity between static and dynamic test results.