SA helmet on a motorcycle?

Just making sure I understand this correctly - There's no good reason you can't wear an SA-rated helmet on a motorcycle, but the opposite is not true since it is ill advisable to wear an M-rated helmet in a race car because of it's lack of Nomex lining, right? Otherwise, the impact protection standard is the same, or no?

There's probably no issue with wearing an SA helmet in an M application, as described here; http://www.racinghelmetguide.com/auto-helmet-ratings.html

The issue I think you would find is how much venting the SA helmet has and how it was done. The SA helmet would probably be extremely noisy in a road speed M application. Earplugs as always are suggested but it may still be a pretty loud situation.

Right from the Snell Foundation:

The SA standard was designed for competitive auto racing while the M standard was for motorcycling and other motorsports. The K standard was released to accommodate helmets used in karting. There are three major differences between them:
1.The SA standard requires flammability test while the M and K standards do not.
2.The SA and K standards allow for a narrower visual field than the M standard (Some SA and K certified helmets may not be street legal).
3.The SA and K standards include a rollbar multi-impact test while the M standard does not.

Bottom line is that in a pinch I would, but not on a recurring basis.

I've done it for years. Many years.

Something to note is that the my SA helmet is heavier than my M helmet. I have an entry level HJC, so if you have something fancier this may not apply to you. I also felt that there was far more wind buffeting with my SA than my M when I was riding.

The smaller eyeport on an SA is what would make me buy another helmet for the bike.

Some SA helmets also carry DOT approval; I wouldn't worry about using one of those on a bike. The biggest concerns I'd have:

• The smaller eye port allowance, as others have noted. Chances are if it's not DOT approved, that's why.
• A lot of motorcycle helmets have liners that are easier to remove and wash. This is less common on SA helmets, but really good to have if you're wearing your helmet every day.
• Weight or ventilation, at least if you're comparing a cheap SA rated helmet vs a similarly priced motorcycle helmet.

I've worn an SA helmet (G-Force) on a bike a few times before, but the washable liner was a big plus for my Scorpion bike helmet.

I have two Simpson Voyager helmets. One is SA, the other M. Only the lining is different.

The eyeport on my motorcycle helmet is probably twice the size of that on my SA track helmet (in avatar). I don't wear the track helmet on the bike.

I imagine that it depends on the manufacturer but if you examine most mid-range priced helmets (< $400 say) they appear to be exactly the same shell and fixed padding with nomex covers on the SA variant. Maybe different vent snaps or shields... same shell though. It makes sense - they have to pay to test each new design so making one for all three tests is the smart play if you can.

I'm sure companies that sell $1000 specialty stuff for either market (Shoei, Arai, Stilleto, etc) can pay to build specialty shells to one test and not the other but my HJC AR is exactly the same as a the HJC bike variant with the removable lining (CL IIRC) of the same year except one has polyester padding and one has NOMEX.

I use my expired SA helmets on the bike.

Cool - thanks for all the replies! I was just daydreaming about the weather warming up and buying a little Ninja 250 or something like that to save gas money on the daily commute (which has increased 25X in the last year), but since the whole point was to save money, I didn't want to have to buy TWO new helmets this year (my current is SA2005, but a pretty nice one and rigged for audio).

You have the other necessary gear too? Armored jacket, pants, boots and gloves?

The largest difference between my SA and my M helmets is the size of the eye port. I have the "large" eye port on the SA helmet and it's still easily half the size, if not smaller, than the eye port on my M helmet.

My M helmet also breathes and vents far better...

Chris, I've got a '71 CB175 that you can borrow, some assembly required.

And I was going to add that most of the M helmets I've ever had have much better visibility than the SA that I own. I don't necessarily know that's the way it usually is, but that's what my experience has been.

BTW(and slightly off topic), I'm pretty sure my current helmet is an SA2005, is this the year that Chump/Lemons/WRL switches to the SA2010 as the minimum requirement?

Duke wrote: The smaller eyeport on an SA is what would make me buy another helmet for the bike.

This/\ I tried my simpson on a bike in a pinch one time, I hated it.

NGTD wrote: Right from the Snell Foundation: The SA standard was designed for competitive auto racing while the M standard was for motorcycling and other motorsports. 3.The SA and K standards include a rollbar multi-impact test while the M standard does not.

This is what I always understood. M is designed to absorb and deform on the first big hit. On a bike you have one big impact (curb, etc) and then not much after. In a car you are more likely to have several medium hits against a roll bar as a car tumbles. Maybe it's true that helmets are the same, but I would suspect that the foam used (that you can't easily see) is different.

For most laydowns, an SA helmet will be sufficient. But for that unpredictable big one, I would trust my life to an M if I had a bike.