Interesting. Where is the evidence to support your claim that BMX helmets provide 'greater' protection?
I'm trying to find something, it's the internet so I will be able to find something to back up my unsupported accusations LOL. But essentially, being harder they don't grip into the ground (especially grippy tarmac) which causes massive deceleration & neck injuries, they slide instead hence skid lid, they tend to cover more of the head offering more protection & as a side effect of that, come off proportionally less in accidents.
Didn't you know, they protect the torso when being run over by tin boxes saving 100% of lives in accidents, every time guaranteed (unless rider dies whilst cycling which causes the accident)
Where is the evidence that they don't grip the ground? We're making presumptions again. Despite this oft mooted claim, and the large ventilation ports in many cycle lids, there is little actual proof that they are any more likely to grab the surface as the impact.
Covering more of the head might possibly be good in impact protection, but that's not absolute. It also has the potential to impact on visibility and hearing. To say that covering a greater surface of the head is automatically 'safer' is simply unproven.
Indeed, the word 'unproven' is quite apt as that's where it's at. There has been no large scale long term study into the issue with any degree of authority. The small scale studies are poor. They're often not objective, setting out to try and prove the researchers viewpoint. They're often not actually srudies at all, but simple reviews of figures.from differing sources who themselves are not empirical in their data.collection. in short, there is little firm evidence cycle helmets work as intended. Conversely, there is little firm evidence that they do not.