Portable Brake Meters New Zealand Limited

Bowmonk Analogue Brake Meter Usage Instructions

Instructions on how to use a Bowmonk analogue portable brake meter.

Please note: Waka Kotahi NZTA are phasing out analogue brake meters
- from 1 June 2024 all inspecting organisations must use an approved electronic decelerometer.

Brake Test Procedure - Bowmonk Instrumentation


Position the vehicle at the start of the test run and place your Bowmonk brake meter on the level section of the vehicle floor.

Installation and Set Up:

  • The meter is set to zero by releasing the thumbnut, tilt the bowl in its pivot’s until the main needle points to zero and retighten the thumbnut.
  • (The meter face should be facing the rear of the vehicle.)
  • Position the recording needle to the left side of the main needle by rotating the chrome knob in the centre of the face.
  • The meter is now ready to use.
Bowmonk Brake Meter


  • Drive vehicle at steady speed of not less than 32 Km per hour and apply brakes smoothly and progressively to bring the vehicle to a stop.
  • Brakes must not be jabbed or snatched or an incorrect reading will be obtained.
  • You do not need to watch the meter. Record reading.
  • Reset recording needle to left of main needle and carry out same test for hand brake. Record reading.
  • Always check manufactures guidelines for the correct test procedures as damage can result to various models. (ie. 4WD, foot applied type, Holden and Ford separate shoe type).


Return the meter to the meter box with this test procedure instruction.


The Bowmonk brake meter is a scientific instrument, indisputable in it’s accuracy. 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 vibrations the instrument is filled with special fluid not sensitive to changes in temperature. The dial is calibrated in percentage ‘G’ the accepted standard throughout the world for measuring acceleration and deceleration.

No maintenance is necessary, however, all brake meters must be sent to an approved certifier for an annual test and calibration as per New Zealand Land Transport Safety Authority regulations.