Hey folks – I have a size 7 3/4 head (US) or size 62cm head (EU) – the only helmet that has ever worked for me is the POC Octal. The new POC Ventral Air version does not.
Unfortunately, I took a header the other day and cracked my lid and am now looking for a new helmet.
Any other riders out there with similarly generous proportions above the neck who could tell me what they wear?
Thanks! 
7 3/4" here, pretty oblong shaped. My Rudy Wing57 TT (L) is the best fitting helmet I’ve ever owned, though it’s a TT helmet. S-works Evade (first gen) fits me well too and is plenty adjustable. Many helmets are too “circular” for my head, but these two are among the best fitting I’ve owned.
Honestly, there’s something to be said for finding the helmet that works for you, and it sounds like the Octal was it…so my recommendation would be just to get another Octal and not worry about it.
Also, I own/wear/like my Octal so I’m a little partial.
Ebay is a pretty good place for finding old model stuff like this. Local shops look to unload inventory. I’ve bought new (to me) shoes and helmet at deep discounts this season. I’d bet there are some Octals out there.
Octals are also still available directly from POC…though probably not that much of a discount.
Edited to add: might be worth reaching out to POC to see if they have a crash replacement program, or at least a discount on a new helmet if you told them you broke yours in a crash.
Fellow man of impressive cranial stature here (7 3/4). I currently wear a Bell Z20, and it fits pretty damn well without making my head look ridiculously huge. I previously wore a Lazer Z1, which I found very to be very low profile and non-bulbous, and a bit sleeker than the Z20. Obviously, helmets are a personal thing and I have not had luck with POC helmets, so your mileage may vary.
It depends on your head shape…I have a big dome and some helmets fit front/back but squeeze the sides of my head.
I’ve recently switched to Specialized Prevail and it works well, as it seems to be wider - still has plenty of room for adjustment on me including with thin winter hats.
I don’t have a big head, but I have an Octal — an excellent helmet. Why don’t you just get another one? Most helmet companies will give you a significant discount if you have had an accident and send in your old one.
I have a 7 3/4 head, used to wear a POC octal which fit fine but just bought a large Giro Synthe which fits great too. Don’t buy an Oakley as they are tiny!
Fellow big head here and i’ve got a Spec Prevail (L) and a Kask Mojito in XL (wish they did other styles in this size rather than just up to an L).
As an aside any tips on an aero helmet for a big head, considering the Giro Vanquish, need decent ventilation as chances are the race will be a warm one (IM Italy).
As mentioned previously, my Rudy TT helmet (Wing 57) fits my large, oblong head shape the best of any helmet I’ve ever worn, and some of the Rudy road helmets don’t fit me very well (Windmax).
Too bad its one of the slowest tested TT helmets out there. Check out Kask or Specialized Evade, or if you’re looking for a TT helmet the Giro Aerohead.
Also mentioned above, the Evade (gen 1) fits me well. Haven’t tried the gen 2. YMMV, but I’ve not found any issues with the Wing57 in terms of speed myself, at least while riding with the visor in place as designed. FWIW, if I found that my Evade was 30s faster than my Wing57 over a 70.3, I’d probably wear the Wing57 because the fit is that much better.
Anyway, it’s an option that works for this n=1’s big head.