Bell vs Alpinestars

No problem 

The "big open port in the face area" is called a "goggle port." Motocross helmets have goggle ports rather than visors that cover the face as motocross riders use goggles for eye protection rather than face visors.

This is for multiple reasons, such as ease of clearing dirt and debris (known as "roost") kicked up by other motorcycles and ventilation.

If you would like me to provide more information about motocross helmets I'm happy to help. Alternatively you could attempt to reach out to Western to hear his thoughts on the Formula's safety. 👍

I have two SM-10’s a Bell Moto 10 and a Moto 9 flex. The SM-10’s are light and used to be my favorite. A few small crashes have kind of got me thinking I should go back to the Moto-10. I quit wearing the Moto-10 because since new the visor wouldn’t stay up. I didn’t know there were little pins on the back of the visor that hold it up. I called Bell and they sent me a new visor and nose piece with no questions asked. That’s pretty freaking awesome. I had a pretty hard get off in a Moto-9 Flex and I never had any issues. The Moto 9 Flex is my mud helmet.

I crashed at speed in the SM-10 and don’t remember a thing. Helmet looked fine but that one has been relegated to pit duty when the promotor requires it. The other SM-10…..man. I’ve had a few small crashes where I face planted and the damn visor didn’t come undone. Both crashes wrenched my neck pretty good and I’m still feeling some stiffness 5-6 weeks later. Also, both crashes I’ve got up seeing double. This is concerning. Apparently seeing double doesn’t mean a concussion. It is consistent with hitting the part of the skull that is over the occipital part of the brain and eyes (front corners) and knocking the vision out of whack for a few minutes. I’m not a doctor but I can Google and I have doctor friends. I’ve never had this problem with any other helmet. 

I know this is all anecdotal so take it for what you will. 

Well, let me educate you just a touch on my personal experience. Maybe my friends Daniel or Vincent can chime in here or Westin.  
I’ve bent a cross bar with my face on a set of renthal 997 breaking my bones just under my nose and my nose itself,  knocking out my teeth as well as my teeth puncturing through my upper lip.. I’m very aware of the space in the goggle port area. Now I did this with a bell moro 9 flex and a set of Oakley air breaks on.  Engine cut out on a wall jump that had a set of rollers before it which I was jumping deep into it.  Sudden stop landing into a roller face did a bit of damage to myself.  Some broken ribs and beat up my knee with a torn meniscus , mcl and a fractured knee cap.. besides the point but I’m very aware of my helmets . I’ve been knocked out quiet a few times as well.  All this shit I’ve just said is mostly irrelevant but it is relevant to my knowledge of helemets and riding. Like I said , the port to the fly is large. I’ve worn just about every new model helmet in the last 10 years.  I ride with a bell moto 10 now, I have 4 of them and they seem to work just fine. Now I’m not talking shit on fly , don’t get me wrong. I could be wrong but I am honest, I don’t know the exact dimensions of the fly but it looks very wide open in the face area. 

I went from a Bell Moto 9 w/MIPS to a Alpinestars SM10. The SM10 is way lighter than the Moto 9, however, I think the Bell fits better. I'm having problems with the SM10 pushing my goggles down on my nose on hard landings. I wear a large in the Moto 9 and bought a large SM10. I did try the SM10 on before I bought it but didn't know it would do that until I went riding with it. If this adjustment doesn't work I'm going to order a size medium forehead pad to see if that remedies the problem. If it doesn't I'll just sell it and order a Bell Moto 9 Flex. The SM10 looks cool and is super light but it doens't matter if it doesn't fit well.

Bell makes helmets, Alpinestars makes boots and fancy road racing leathers.

I personally have many MIPS helmets. 
 

while this report is for bicycle helmets, they say non MIPS perform just as well as MIPS helmets. They reference other brands, maybe they are tested somewhere else. 
https://helmets.org/mips.htm

Helmet and brand rankings: 

https://www.helmet.beam.vt.edu/bicycle-helmet-ratings.html

I hear you, but Alpinestars is pretty dedicated to motorcycle rider safety. Bell is a large helmet company with hundreds of products. Hard to decipher what one spends more resources and talent on their dirt bike helmet.

I think the adjustment will work for you. You can adjust just the front two snaps or all of them. I’ve seen a number of people surprised what a difference it makes. 

Exactly, astars is a protection company and makes some incredibly technical pieces. I would say the fact they developed by far the best stand alone airbag system for road race and now rally should give them just a little bit of street cred. They are heavily invested in helmets and are about to come out with a roadrace helmet too. 

I have an SM10 and a Formula Carbon and love them both. The Fly fits my head a little better. They feel like they weigh about the same. No complaints on either. Tried a bell 10 and felt heavy and uncomfortable. 

I was just about to post a link to the Virginia Tech helmet site. I have used it a few times for helmet decisions, especially since May 2020 when I sustained a TBI in a cycling crash. I do like that it objectively shows some mid-range helmets outperform the top-dollar offerings from the same company.  There is absolutely no way a company like Giro, Specialized or Bell would ever publish that information.

I am surprised they have not tackled moto helmets yet, but maybe they will work their way up to it.  The dynamics of a moto crash are much more complex than (IMO) cycling, hockey, football, etc.

Shoei or Arai, but that’s just me.