As one of the reasons we're going to the BMF show is to find a better fitting helmet for my other half, it seemed only fitting (pun intended) that I should post a helmet fitting guide.
So, without further ado, here is one shamelessly borrowed from the UK's Direct.gov website.
We recommend you invest time trying on as many helmets as possible. Once you’ve found those that fit you best, you can then choose the helmet with the highest SHARP rating for the best possible protection.
Every head shape is different, so we’ve pulled together some tips to help you choose the right fit.
1. Get measured
Your safety is too important to simply guess your size. Before trying on any helmets you need to make sure you know your exact head size. Measure around your head just above the ears and take a measurement at the forehead. This measurement is a good starting point and will correspond with a particular brand's size (always bear in mind a medium in one brand may be different to medium in another). Getting the right fit is paramount, so don't be tempted to go for another size if your dream helmet is out of stock.
2. Try it on
Ok, so you've chosen a helmet to try. Now place it firmly on your head, securing the chin strap so you can fit two fingers between the helmet and your jaw. If the helmet has a quick release buckle then take your time adjusting the strap. Once on, you should be able to feel the helmet against the whole of your head - without feeling ‘pressure points' or the helmet leaving red marks. Once you're happy, keep it on for a few minutes to make sure it's comfortable.
3. Check the fit
Secure the strap and try rotating the helmet from side-to-side. If you're wearing a full face helmet your cheeks should follow the helmet's movement, while remaining in contact with the cheek pads firmly and comfortably. If the helmet moves or slips on your head it's probably the wrong size. Next, try tilting the helmet forwards and backwards. Again, if it moves or slips it's probably the wrong size.
4. Will it stay on?
You want to know the helmet you buy will stay firmly on your head in a crash. Make sure the chinstrap is done up and tilt your head forward. Ask someone to try and roll the helmet off your head by carefully pushing up from the rear of the helmet at its base. If you can roll it off in the showroom, then it's sure to come off in a crash.
There's also a snazzy animation, showing how to carry out these steps, here