Why are moto helmets the way they are?

Visors are used to duck roost and help when the sun is low. Goggles over a full face shield prevents goggle fog since speeds are lower than motogp and there is less airflow. And lastly, id look so dumb going midpack C class speed with a street bike helmet. 

Dust

Tell me more about getting roosted in the face 

😂 

I think that there was some wicked crash at Saddleback that ended open face helmets. Subsequently banned from pro racing.

As for today why are they look this way,  I think it is the cabal of goggle manufacturers that keep us from simpler designs. /sarcasm. Don't know. 

Most goggles and some helmets come with a roost flap that can be added or removed. 

That could be eliminated with a neck seal.

I think this probably illustrates why they are the way they are today. This is where we started from, chin bar was added, minor tweeks from there. This is what we're used to and going to be hard to get enough people to try something else to ever make it worthwhile for a manufacturer to try. Airflow and weight would be issues as well I'm guessing. 

No one is telling OP he can’t go wear a street bike helmet

Lot of companies already have some version of dual sport helmet similar to what OP is describing 

https://hjchelmets.us/pages/rpha-60

When trail riding I use one of these

Seems like that would be super hot and uncomfortable.  Especially for off road racing/riding where you have your helmet on for hours at a time.

Someone tried this in the 90's, I think. Saw a couple at the track.

It looked like a moto helmet with a visor, but it was closed with a shield like a street bike helmet. 

Maybe it was Scott? I don't remember who.

That would be so incredible hot. 🤣

I use a Bell Moto 9 Flex with 100% Armega goggles.  The close to the face chin piece and slightly larger goggle frame leave me almost 0 space for any rock to get through.  Maybe a new helmet/goggle set up is the answer.  I think the reason we stick to the style we do is likely, as some have stated, better air flow at slower speeds.  Its hot enough already even with the high flow vents in helmets, boots, gear, ect.

I think it is mostly heat related. Speeds are relatively slow in moto/trail riding so air flow is important. 

Years ago I did some pre-production testing for a helmet company and when the discussion of vents with sliding vent covers came up I told them to not even worry about vent covers. That in all but the coldest conditions the vents are always open anyway and when you crash they break.  I said they should put in as much venting as the the good while maintaining strength integrity.  And the helmet will be lighter as a bonus. They actually seemed surprised but the other testers agreed with me. Who knows.  For the OP, you should look into a dual-sport helmet that is basically a moto helmet with a face shield. 

I think it is mostly heat related. Speeds are relatively slow in moto/trail riding so air flow is important. 

Years ago I did some pre-production testing for a helmet company and when the discussion of vents with sliding vent covers came up I told them to not even worry about vent covers. That in all but the coldest conditions the vents are always open anyway and when you crash they break.  I said they should put in as much venting as the the good while maintaining strength integrity.  And the helmet will be lighter as a bonus. They actually seemed surprised but the other testers agreed with me. Who knows.  

For the OP, you should look into a dual-sport helmet that is basically a moto helmet with a face shield. 

Because you'd overheat and cook your head in a street bike style helmet/visor. 

I just recently got sponsored by LS2 helmets. I have the X-Force Carbon and it has a big Darth Vader looking mouth/chin guard with a big rubber roost protector and it looks kinda crazy. With my goggles on, it is a tight fit but there's definitely less room to get smashed in the face/mouth than with my previous Bell Moto-9. It pops out easily if you want to take it out for more ventilation. There's way more ventilation in the shell of the helmet. I know LS2 isn't quite a trendy, big name but I really like mine. They also make an adventure style helmet with a face shield. 

On my dual sport and adventure bikes I usually ride with the face shield up with safety glasses on.  Gets hot in there.

would a street bike helmet safer ? seem like there are room for a more safer style helmet but i cant se it looking good enough for people to use it.

For UTV's and off road trucks they have 'pumper' helmets that have a neck curtain to keep the dust out. But they have an air pumper that pushes fresh air into the helmet to keep you cool and to also help keep dust from creeping in.  Problem is the pumping system isn't exactly small or light so using something like this would be basically impossible for moto.  Air flow and dust is the main reason we are using the current helmet and goggle design.

Way to hot and dusty where i ride but depending on where and how you ride this may work.

XD-5 | Cosmic Yellow | Arai

That's what I bought to use with the 690 Enduro. I wore it once and went back to the full moto helmet and goggles. I think I'm just used to the venting from an open lid vs the closed up face shield... plus there's not much dust only riding around town and to the beach 🙂 

I think that was "Nolan" that made those.  I vaguely remember them.

That would be like wearing Seer goggles.