In the UK, Bowmonk brake test meters are
approved by the MOT and DOT departments for use in the annual vehicle-testing
scheme. Wherever brake testing is mandatory by law the Bowmonk Brakemeter/Dynometer
is an approved brake test instrument. We are a fully approved UKAS/NAMAS testing
laboratory and we recalibrate and repair both the Tapley as well as our own portable
The Bowmonk Brakemeter/Dynometer MKIII is a scientific instrument, indisputable in its accuracy as it is based on one of the basic laws of applied physics. It consists of a finely balanced pendulum free to respond to any changes in speed or angle, working through a quadrant gear train to rotate a needle round a dial. The dial is black with silver white graduations and having a linear length of 5 1/2 inches (114mm). To damp out all vibration, the instrument is filled with a special fluid not sensitive to changes in temperature. No maintenance is necessary.
The dial is calibrated in percentage "G", the accepted standard throughout the world for measuring acceleration and deceleration. There are no connections to the vehicle other than mounting either with two self-tapping screws on to a heavy stand (as pictured above) or the suction cup operated by the small side lever. In the latter case smear the suction cup with glycerine, or Vaseline to increase adhesion.
Test the vehicle on reasonably level road. The meter is set to zero by releasing the thumbnut, tilt the bowl in its pivots until the main needle points to zero and re tighten the thumbnut. The meter is now ready for use, it is not necessary to watch the instrument continuously as it is fitted with a recording needle. Depending on the test to be performed the recording needle is positioned to left or right of the main needle by turning the centre chrome knob, and will accurately record the maximum reading.
Bowmonk Limited, Diamond Road, Norwich, Norfolk, NR6 6AW, ENGLAND