The specifications of some small-to-middle-weight new bikes have caused disquiet on the forums of MCN this year.
One user wrote of the new Honda CBR250R, which weighs 162kg and makes a claimed 26bhp: “I can't believe how heavy these things are. Modern four-cylinder 600s are down to this sort of weight.”
Another user said both the CBR250R and the 169kg Ninja 250R were “about 25kg too heavy”.
BMW’s new G650GS, at 192kg, has also raised eyebrows.
But there’s good reason the numbers seem high. It’s because manufacturers have started quoting kerb weight, with bikes full of fuel and oil, instead of dry weight, with no fluids.
According to an insider at one of the Japanese manufacturers, tricks played in the past to keep dry weight figures low include removing tool kits and draining batteries. He said kerb weight was now used instead because “all the manufacturers agreed that the figure should refer to the motorcycle complete”.
A 600cc sports bike with a claimed dry weight of around 160kg could actually have a kerb weight of around 180.
Bike weights are also under European Commission scrutiny thanks to licensing rules.
A raft of changes from 2013 include new power and power-to-weight ratio limits for new licence holders.
At the moment they are restricted to 33bhp and 0.16kilowatts per kg for two years after passing, but this will rise to 47bhp and 0.2kw/kg.
The 47bhp G650GS meets these restrictions precisely. It makes exactly 0.2kw/kg. If it weighed 1kg less, it would be too light.
Similarly, the Ninja 250R, based on its kerb weight, makes 0.14kw/kg, not far off the current limit of 0.16. And the CBR250R isn’t far behind at 0.12kw/kg.
However, our source said: “If the switch to kerb weight coincides with European licensing directives, I think that is coincidence.”