I haven't tried these one, but I always either try before I buy or order from places with a good return policy. You can never tell if a helmet is shaped for round or oval heads, or is suitably adjustable.
These Riv helmets look too hot for my head, but my head runs hot even if I'm asleep. I have a POC MIPS helmet which has ventilation which works ok for my head.
I understand where Grant is coming from regarding helmets, but he's confusing several different hypotheses about helmets into one confused hypothesis if one is contemplating whether to wear a helmet or not:
1) Does wearing a bike helmet reduce or increase incidence of serious injuries, and which kinds of injuries?
2) Does wearing a bike helmet cause or prevent serious injuries, and which kinds of injuries?
3) Which types/models of bike helmets are better or worse at causing or preventing serious injuries?
4) Which models of helmets are more durable?
4) Does wearing a bike helmet result in a reduction or increase in reckless cyclist behavior?
5) Etc,
One can always avoid becoming a reckless cyclist oneself once you place a helmet on your head. My wife has worked with people suffering from traumatic brain injury, and from what she's told me, wearing a helmet and riding cautiously is the way I want to ride.
John