Weight Bags

All vehicle manufacturers specify maximum kerbside weight and maximum permissible axle loads for each model in their range.

Car manufacturers, importers, dealers and specialist workshops often need to place loads in their vehicles to simulate passengers and luggage.

Typical examples would be to simulate ride and handling at maximum permitted loads, or to check steering geometry in a laden condition, or to check ground-clearance when laden, or perform dynamic brake testing carrying a full complement of driver and passengers plus luggage.

Many of these requirements can be driven by warranty claims which are impossible to verify without imposing similar loads to the loads carried when the complaint arose.

A motor industry standard vehicle occupant weighs 75 kgs. 

The need therefore exists to have a method whereby loads can be applied in multiples of 75 kgs, and also for some specialist purposes fractions of that 75 kg.

For example, most vehicles have a clearly defined rear-axle max. load, but do not define what the maximum weight can be placed in the boot (trunk).  In this case, 75 kgs are applied to each of the 2 front seats, and 75 kgs are applied across the rear seat and the weight is measured under each rear tyre footprint.  The difference between the sum of the rear tyre footprint weights and the maximum represents the available load in the luggage compartment – or more importantly – as a nose-load imposed on the tow-bar.

Many tow bars are sold as an accessory with a clear maximum nose-load (typically between 70kg and 100 kg) but almost never is this additional load at the extreme rear of the vehicle taken into account when calculating spare load capacity in terms of rear axle maximum load and free suspension travel.

Comptek were asked to come up with a system which allowed typical occupant plus luggage loads to be imposed in the correct areas of the vehicle (seats, boot, etc.).  Two main criteria were evident –

1. the loads must be easily handled without the need for mechanical handling equipment

2. must not soil or damage the interior upholstery.

Comptek have designed and manufactured a unique set of weight bags to solve this problem.

Each bag weighs exactly 12.5 kgs   ( calibration certificates can be supplied)

Each bag is manufactured to Comptek’s registered design using a dual-cell of an RF-welded impermeable polyurethane bag encapsulating lead shot sealed within a canvas outer sheath with carrying handle. 

The inner cell ensures two vital elements:

1. Atmospherically sealed, the weights cannot corrode or change value
2. Leak dust which could stain or mark velour or leather upholstery

The outer canvas sheath performs two functions:

1. Wipe clean outer surface to eliminate risk of soiling customer’s upholstery
2. Provides handle to ensure that loading, un-loading and storage all fall within Health & Safety guidelines for manual handling

Storage is provided in the form of a trolley.  It must be remembered that MPV’s which have up to 8 seat capacity require 8 x 75 = 600 kgs to simulate passenger load, plus additional load in the luggage compartment.

Therefore, we are talking about storing and deploying up to 800 kgs – and a trolley to get the dummy weights as close as possible to the test vehicle during loading and un-loading is highly desirable.

The trolley can also accommodate vehicle weighing equipment consisting of 4 weigh-pads with associated ramps and digital read-out display which enables users to achieve  accurate foot-print weight values to the nearest kilogram.