Even a good fitting helmet will not prevent the possibility of it becoming detached from your head in a crash.
I was the expert in the case of Finnis v Caulfield where the well fitting helmet on Mr Finnis came off on impact with the car driven by Caulfield.
The third party insures admmited liability in respect of causation, but stated that the injuries were as a result of the helmet being eith a poor fit, poor quality or it was undone.
To cut a long story short, I was able to prove that it was a perfect fit, it was secured and it was in good condition.
As part of my investigation, I interviewed the chief medical officer of the FIM who is based at the John Radcliffe who had undertaken a study of helmets coming off as a result of a crash even though they were fastened.
3 GP riders in the 250 class had crashed, all of them had factory sponsored and fitted helmets and all of them had them done up at the time of the crash.
There were also a number of examples of diffuse brain injuries again where the helmet had come off in a crash involving ordinary road riders.
The nub is that in certain circumstances, the head can shrink momentarily, but sufficiently for it to allow the helmet to roll off the riders head.
It happens so quickly you won’t know it has happened, but it will give the illusion that it was unfastened or a poor fit.
Subsequently I have dealt with several similar cases since Finnis which was in 1999 and was one of the reasons why I was asked to become a consultant to some of the big helmet manufacturers and why I was a member of the BSI helmet technical committee for many years.
With a flip front helmet, you increase the chances of a fracture to the base of the skull (broken neck) by about 60% and there was a time when they came very close to being outlawed because of the number of fatalities that occured in this type of helmet.
They have improved to a degree, but you still run the increased risk of breaking your neck fataly wearing a flip front compared with a conventional full face.
Australia is still considering banning flip fronts and they are also on the verge of banning open faced.
As a by the by, in the Finnis case, the third party insurers offered £50,000.
The case was settled for £1.5 million (brain damage) and is the most reported motorcycle accident case in UK legal history, so I am quite proud to have played my part.