SO, WHAT DOES ‘KERB WEIGHT’ MEAN ANYWAY?

LET’S TAKE AS AN EXAMPLE THE BMW Z4 M Coupe of 2006-2009. Conceivably, the quoted weight of the little coupe could vary by as much as 150kg depending on which standard it is measured against.

The kerb weight that we like to quote here at evo is the the DIN figure – that’s Deutsches Institut für Normung, or German Institute for Standardisation. This is the weight of the car with all the fluids necessary for operation, including a 90 per cent full tank of fuel. For the Z4 M Coupe this is 1420kg.

BMW also quotes an EU kerb weight (sometimes called EEC kerb weight) of 1495kg. This is the DIN figure plus an extra 75kg for ‘driver and luggage’, and is the weight declared for emissions testing.

There is also a ‘dry weight’, which has no standard and is open to a number of interpretations. The most straightforward is the car with an empty fuel tank (as sometimes quoted by Lotus), but there is also a ‘shipping’ dry weight, historically used by some race car manufacturers and Italian sports car makers. This means no fluids whatsoever – no oil in the engine/ gearbox/differential, no coolant, no air con refrigerant, no battery acid – and also no toolkit, spare wheel, handbook, etc.

Quoting a dry weight can therefore make a car’s weight, and by extension its powerto-weight figure, appear far more favourable than those of rival cars using DIN or EU figures. This is why we mark dry weights in the Knowledge with an asterisk.

A separate issue is Gross Vehicle Weight (GVW). This is the maximum the vehicle can weigh on the road when loaded with passengers and cargo.