How tight is your full-face lid?

If it’s I uncomfortable after 10mins then it’s too small. Snug, not tight.

Also remember that different brands are different shapes, so worth trying as many as you can get

I bought a motorcycle helmet, slightly on the small size, with the hope it would break in and become more comfortable. It didn't. £300 mistake.
Find the full face design that fits. Not the one that you want to fit but doesn't.

I’d try a different brand, preferably one with swappable cheek pads so you can alter the size. A too-big helmet will wobble around and make glasses or goggles a nightmare, as well as being distracting and probably not as safe in a crash. A too-small one will give you a headache pretty rapidly, and probably make you feel like you can’t breathe as easily. Different brands have different shapes, I reckon you’ve just tried on one that doesn’t suit. If you’re really struggling for fit, look for one that has a cradle adjustment inside like you’d get on a trail helmet.

Echo above, try a different brand. I'm on the cusp of medium and large in Giro (open face) helmets and wasn't happy with the fit of recent ones I tried. I'm now very comfortably within the middle of the sizing on a large Lazer helmet.

My DH full-face is an old 661 Comp in large but rarely gets worn. It's a great fit though, near perfect for me in that it doesn't really move around. I've also got a Giro Switchblade in large which is superb: benefits of the cheek pads for snugness along with the adjustable cradle at the rear for extra secure feeling. Most stable 'full face' helmet I've used.

My first Proframe was a medium & the chinguard was pretty close to my face. The helmet did it's job the way it should when I did crash.
Now I've got a large with the fatter cheek pads and a bit more space to the chinguard. Probably what I should have got all along.
The new Proframe RS looks bloody good.

I’ve tried a small and medium size of the same lid.

Try a different brand.

Yeah - just try more brands on until you find a good fit. Snug but not tight.

I’d say my 7idp cheapie one is the perfect size for me by our luck (impulse purchase at BPW quite a few years back).

On the flip side my Ixs Trigger feels so good on I forget it’s a full face helmet. I think this is mainly due to the light weight, plus it has an adjustable cradle with a dual in the back like normal half shell helmets. I think it’s DH certified too.

as others have said, try some other brands or models.

I was after a FF for the Megavalanche this year.

Tried a few...

IXS Trigger FF - Medium - too small, Large - too big.
TLD Stage - Medium - too small. Didnt try a large.
POC Otocon - Large - too big. Medium - good fit. bought one in green, fitted well. wanted white, so bought the same size... didnt fit, was too small?!?!
Fox Pro-frame - medium - a bit small. Large - felt good. Then i had my hair cut and it was too big?!

A few of them felt like a good fit, until i grabbed the chin bar and rotated the helmet forward, which it would then totally rotate and cover my eyes. So a good fit turned out to be a poor fit!

So i ultimately dusted off my old Fox rampage pro carbon and wore that.

Sorry, maybe I've been a bit vague, the medium feels like an absolutely perfect fit fresh out of the box. The basis for my quandary is will not be so secure once it has bedded in. Hence if maybe I should take the small, with the theory that it will feel more like the brand new medium once it is broken in.

I wear a small motorcycle helmet and although that has loosened up over the years is still a tight fit. I'm happy with that on the motorbike, but I wonder if that would be too much to cope with alongside the exertion of a pedal bike.

I guess what I really should have asked was, did your FF lid perfectly when you first got it, but does it feel too loose now?

Ah - both full face helmets feels exactly the same now as when they were new. I don’t think it’s like shoes where they can stretch etc - and if you knacker the pads inside you can usually buy new ones.

Get the medium. The small one will never fit. I have a large 7idp one. It's fit hasn't changed over time that I have noticed. Getting a haircut probably has a bigger effect than worn pads.

TLD say it should be tight enough to pull your face skin, scalp about when you move the helmet.

Does the Medium do that?

I'd be very wary of buying uncomfortable so it'll be comfy when it gives a bit. Wasted money in the past buying climbing shoes and snowboard boots on that assumption.

bot a fox full face and went ip a size form recommended base don google reviews - it was till chuffin tight but after two days of wearing now feels just right.

bot a fox full face and went ip a size form recommended base don google reviews – it was till chuffin tight but after two days of wearing now feels just right.

I think I know what you mean but your spelling has gone to pot, maybe excess pressure on your brain from a tight helmet? 😀

Sorry, maybe I’ve been a bit vague, the medium feels like an absolutely perfect fit fresh out of the box.

Get that one.

They don't get noticeably looser IME.

My full-face lid feels just as snug as when I got it. Bell Super-3R iirc.

the medium feels like an absolutely perfect fit fresh out of the box

Hunt over. Buy it. Wear it. Don't look back.

I tried XS/S TLD Stage having measured my head as fitting firmly within that size bracket. It felt fairly comfortable and snug but after 10 minutes I would get an awful headache, I assume from the helmet putting pressure on my head somewhere. By all accounts the M/L should have been too big and I thought that maybe the TLD Stage just wasn't fit for me, but I don't regret sticking with the M/L and I think it's a good middle ground between tight and loose. Based on your description I would go the medium or a different brand entirely as downsizing helmets is not fun.

Try lots, but the one that fits (and doesn’t look too stupid.

Can you get replacement pads for the medium?