Helmet design question

[Fencer]

The full face street helmets we wear are rounded with no points to speak of presumably for both areo-dynamics and safety.

Why then are Moto cross helmets shaped to a "V" more or less at the mouth/chin area with a long visor at the top? The visor I can see for a sun shade. is there another purpose? I just don't get the "V" though.

Just curious.

 

[TriggerT]

I THINK it is to allow the rider to breath more easily, and provide additional room to keep your chin from contacting the front of the helmet. Just my $0.02.

 

[James Burleigh]

I have wondered the exact same thing. Put another way, Why are those helmets so GD funky looking??? :huh:

 

[HaulinAshe]

The shape of MX helmets is to give more space for a face-plant without contacting the mouth. It also has to do with the fact that us MX folks wear goggles with the strap over the helmet. That requires the sides of the helmet to be slimmer and helps contribute to the funky shape. The visor is used as much for roost deflection as it is for sunshade, actually more.

When you are about to get a blast of dirt/mud/rocks in your face, you tuck your head down and use the visor to prevent getting your face filled up.

Another, less-known use of the visor, is for aerodynamic steering. When you screw up and don't realize it until you are about 20 feet up, you can tilt your head back for drag!

 

[SkooterG]

A most excellent response by JeffAshe!

All I know is I wouldn't want the visor from one of those MX helmets catching air at 120mph+. Things could get, errrr, a bit exciting.

 

[Bustanut joker]

A most excellent response by JeffAshe!
All I know is I wouldn't want the visor from one of those MX helmets catching air at 120mph+. Things could get, errrr, a bit exciting.

Been there done that! Well kinda like that.

I forgot to drop the face sheild during a 1/4 mile blast against a buddys warrior :dribble: . Needless to say when came outa my tuck and the wind caught the sheild and lifted the chin bar over my eyes :gah: , Well lets just say it was interesting

:jester:

 

[shokdimn]

Jeff,

Impressive!

 

[jestal]

To add to what Jeff said.....the visor is also handy when trail riding in the woods when a branch or limb is in the way. If you don't duck or have some way to deflect the branch it whips you across the face thru the open helmet port. Tip your head down quickly as you approach the limb(s) and the visor deflects them over the top of the helmet. If you don't duck down far enough it can deflect the limb so it whips you across the neck so you want to keep the visor down but angled up. Don't ask how I know this....

The chin bar is elongated to allow more clearance from your mouth to the bar for a face guard attached to goggles and just to give more room for movement and breathing. You are usually breathing pretty hard halfway thru a moto so the extra room to the face bar definitely helps with the ventilation if you catch my drift.. I think the extra distance to the face bar also adds significantly to crash protection. There is no question that you are MUCH more likely to "use" the helmet on a dirt bike and your first face plant will help you appreciate the extra room from the face bar to your teeth.

 

[Rickster]

While Jeff and Jestal may be technically correct, i really believe it's all about marketing....

see---

if all you needed was a single helmet, sales would drop, and people would lose their jobs, there'd only be one brand winner.

There must be specific helmets designed for dirt, road, cars, trucks, 4-wheelers, etc.. they gotta have style... they gotta sell... they gotta make new markets.

 

[Fencer]

To go with Rickster here:

Apart from Jeffs air drag on the visor and a little more mouth room over a full face. Why could you not were a full face for dirt?

The only other thing I can come up with is fogging. By wearing goggles and seprating your breath from the shield area you are less apt to fog. Unless you have a no fog Scorpion helmet like me

 

[HaulinAshe]

Apart from Jeffs air drag on the visor and a little more mouth room over a full face. Why could you not were a full face for dirt?

You could certainly wear a full-face street helmet for general dirt riding, just not motocross.

It would be possible in the cooler temps. In the summer I would absolutely suffocate. A typical MX moto is like running up and down a hill, just as hard as you can go, for 10 minutes. Also, the weight would be a huge problem. There have been many times that I've suffered whiplash from a violent landing or sudden stop on a MX track. Not sure what the exact specs are, but I'm pretty sure my MX helmets weigh several hundred grams less than the typical street helmet.

The visor would be another issue. Without the specially designed sides to allow for goggle straps, you would be forced to use the shield on a full-face street. That would last about five seconds before it became so covered in mud/dirt/dust that you had to flip it up. Tear-offs would be pricey and BIG.

I'm sure it COULD be done. But you would not last one lap behind me. My aim with the rear tire is legendary!



If I did occasional recreational dirt riding and didn't want to spend the extra bucks for dirt helmet, I'd have no quarrels with using a full-face street helmet. And the same thing applies for using a MX helmet on the street. I actually have more confidence in my MX helmets when it comes to protection. Mainly because I have tested their design over and over and over and... Oooooh bad memories!

 

[jestal]

It goes way beyond marketing. There are definitely different helmets for different purposes. No way would a standard full face helmet work on a motocross track. Goggles are absolutely the only way to ride a bike in the dirt and they just will not work with a normal full face helmet. And if you have ever been pelted in the face with a roost from a rear tire there is absolutely no way you would with a helmet without a visor to deflect it in the future.

There are other differences in MX helmets besides just the shape and visor mentioned. Due to the exertion of MX the MX helmets have MUCH more ventilation and very "open" padding to allow air circulation and prevent the absobtion of sweat. A normal street full face helmet would weigh 5 more pounds by the end of a moto due to the sweat it would soak up in the padding. And you would sweat far worse in a street helmet due to the closed shield and less ventilation. MX padding is open mesh like materials...kind of like soft scotchbrite material to prevent soaking up sweat.

Even on snowmobiles there are several different helmet styles for different purposes. Full face and shields work fine for normal trail riding but snowcrossers revert to the MX style helmet and goggles due to the roost problem and fogging. Trail riding with goggles and an open MX style helmet just doesn't work due to frost bite at continuous speed. There you have to have the full coverage and a shield to seal things up....and an electric shield to prevent fogging.

There's definitely more than marketing going on in helmet designs for different applications.

I used to ride a jet ski a lot and several of my buds and I would meet once a week at a specific lake for a bit of jet-ski-X racing around buoys. Those standup jet-skis were about as tiring when racing like that as MX racing on a bike. We would also wear helmets as there was frequent "contact". An MX style helmet worked pretty good on the water for as long as it could drain easily when you went in. That is where the open mesh padding really would prove its worth.