Re: helmet
 

Maybe a helmet dealer or tech guy can confirm this but it's my understanding that a M rating is constructed differently than a S rated one. The difference is a M hat is designed to protect a one hard hit, ie fly off your scooter and slam the pavement while the S hat can protect multiple hits ie slapping the inside of your roll cage when barrel rolling thru the lights.

Re: helmet
 

Hacksaw, no helmet is built to take multiple hits. And no matter the construction five years is recommended as the replacement interval. The SA rating affords fire retardant materials and my experience is the nomex or similar interior fabric is softer...kinda like sleeping on high count sheets vs Walmart brand..to each his own.

Re: helmet
 

I love my HJC CL-17 helmet. Very comfortable and very affordable. I wouldn't trade it straight-up for my brother's far more expensive Simpson Bandit.

Jeg's site still has them at Snell 2010, but Summit lists them as Snell 2015.

Re: helmet
 

Checked the Snell website. A rating of SA does have fire protection in the liner, a smaller opening and must pass a roll bar impact test.

Re: helmet
 

That is my understanding, the M is not designed for repeated roll bar contacts.

Re: helmet
 

M rated helmets have a larger peripheral vision.

http://www.smf.org/helmetfaq#aSAMKdiff

What are the differences between the SA, M and K standards?

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:

The SA standard requires flammability test while the M and K standards do not.

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).

The SA and K standards include a rollbar multi-impact test while the M standard does not.

Re: helmet
 

Think you guys are misinterpreting the cert tests...just because a SA helmet is tested for impacts which you cannot measure doesn't mean it will be free of damage and able to sustain subsequent impacts. But everybody has to make the call to their satisfaction, just pointing out a SA helmet is an added safety measure but doesn't offer any guarantees.

Re: helmet
 

A helmet with SA rating must pass a roll bar impact test. Helmet with M rating does not need to meet this requirement. They may be made by the same company, same construction or MAYBE NOT. Why take the chance, unless your one of those racers that leaves first and spins his head around like Linda Blair at the 300' mark and having a larger view window is more important than your brain being scrambled. Also note that any impact, like dropping your helmet on the ground can damage the crushing properties of the inner liner. Manufacturers recommend you return it for checking/repair or replace it.

impact 1320
 

I have been trying to buy a impact 1320 large in white for 6 months, they keep pushing the build date ahead.

Re: helmet
 

I never ran at a track that didn't have full metal guard rails at a minimum (US-13). All the tracks I run at have the Jersey Barriers. I'll stick with them. I'm not relying on my helmet to protect me from inferior race tracks, too many good ones around here to take a chance.