Tom Ds editorial and helmet fit

I just read Tom Ds most recent editorial and, among many things, was struck by the fact that I know very little about helmet fit. I try to be careful with a lot of the elements of bike fit, etc… and have learned a ton from reading this and other forums, but I realize that I know next to nothing about how my helmet should fit. I certainly don’t have any real reason to be confident it won’t fly off in a crash.

What I’m using now is an older Rudy Project and, truth be told, I bought it mail order with low price being a principal consideration. I realize now how stupid this is.

So, before I go out to TRY ON helmets, would someone like to comment on how I should fit/size my next helmet? Are there brands that have particularly good fit and retention mechanisms?

Thanks in advance.

How big is your melon? If you can fit a Louid Garneau Med, let me know ASAP and I’ll get off my ass sending you that box. We can’t can’t have Tibsy riding sans lid!

I am not begging parts!!! I have went on the wagon!!!

Shut up and just tell him whether or not you fit a medium!