SNELL helmets transfer more joules of force to your head than the softer DOT helmets do. This is a proven fact. Cycle World did a test on numerous helmets (Blowing the Lid Off was the name of the article) and the best performing helmet, trnsmitted the least amount of joules to the head form, was the cheapest. SNELL helmets are made to withstand SNELL testing which call for unrealistic hits "pointed projectiles" (page 7 of the SNELL standards
www.smf.org/stds.html ) which require a harder shell which transmits more energy, joules, to the brain.
Of course you don't have to take Cycle Worlds word for the amount of joules transmitted, you can take SNELL's word instead-
www.smf.org/articles/dot.html
As you can see SNELL standards accept a max of 150 joules, much higher than the amount of force allowed by DOT. From what I've seen the EN (European standards) would be the best. Where SNELL is better than DOT is in the peak g's allowed in a crash.
According to the SNELL site
www.smf.org/articles/mcomp2.html
DOT does require a retention test, contrary to your post.
Lastly bear in mind that SNELL is nothing more than a business who makes money off of its certifications, period. The SNELL Foundation has ignored anyone, including Harry Hurt (for those of not familiar he was the author of "The Hurt Report"), who dared to question them. Ironically they are in the process of changing their standards to come in line with the crticism.
The controversy will go on for as long as the advertising companies can convince people that more expensive helmets are safer. Unfortunately that was NOT the case of the study done by Cycle World where the cheapest helmet outdid all others.
At the end of the day we each make our choices based on available info and our convictions, at least we're wearing helmets.
Edit: My bad, the article was in Cycle magazine.
I dont think I ever said that DOTs actual standards were insufficient or faulty I did however comment on there implementation. The DOT standard i actually pretty good for what it does test, it isnt comprehensive enough though. You mention the Joules used in testing, dont confuse joules, or the energy transmitted to the
helmet with G's or accelerative forces transfered to the
head. Yes Snell uses 150J whereas DOT uses a max of 109(BSI is closer to Snell at 141, and EN is the highest at 157) but this is GOOD, they are providing the largest hit but requiring the head to recieve a lower maximum force. So even though Snell beat on the helmet harder the head isnt allowed to feel as much as the DOT is. Where the DOT is superior is in its time limits even though it has a higher peak, it isnt allowed to receive as much force for any extended amounts of time, even though Snell belittles this portion of the DOT standard and instead stays by their way of only recording max levels the DOT way is better(even though their max is too high) Think about, Snell doesnt car how many times you get hit at 299G's(299 times the force of gravity) or how long you are subjected to that force, so long as you dont hit 300. Sounds f'd up when you think about like that doesnt it??? Ever been hit in the head?? Every blow compounds the pain/injury doesnt it??? So the DOTs exposure limits are a GREAT idea. the EN standard has the lowest max acceptable force, obviouslt good, combined with the DOT exposure tier and youd have the perfect impact regimen. Snell also poopoos on the idea of the EN's kerbstone anvil, I think its a good idea, if you look at why Snell says it bad....well thats actually why its good. Snell also belittles the range of motion allowed in the helmet during EN testing, well again if youve ever hit your head you know that it moves around, so I say a more natural test is better, eh?
Snell(and BSI) also only test with one weight headform, they claim that head size doesnt affect head mass.....um, really??? Do we need to discuss this one? DOT and EN for the win here as well.
I stand corrected, the DOT does test retention, but only static retention(no movement involved) and thats where it falls short, Snell uses dynamic retention tests and so do the BSI and EN, who get the win on this category by having the more comprehensive and in some way tougher tests, the DOT nor Snell test for harm caused by the strap to wearer, retention/release durability, strap movement, or accidental release.....all things I think are important, how bout you?
All except for the EN standard test for puncture resistance, a good thing. BUT the reason the EN doesnt test for puncture resistance is because they dont allow punctures, they instead have a maximum deflection, meaning the shell must must deform no more than a certain amount and must return to within a certain amount of new after the deformation. Lets call it a tie....but I prefer no punctures
A key test that the EN and BSI perform and the Snell and DOT dont is an oblique test, or one for glancing blows. BSI and EN helmets are both tested on an abrasive rig that measure how well a helmet slides or how aggresivley it or any of its parts grip or snag on the ground, potentially twistig the helmet and neck. BSI/EN FTW.
We have discussed the shortcomings of DOT qualification and its administration but not Snells. Snell performs their own independent post release testing, meaning the Snell foundation itself tests and certifies the helmets(a good thing) BUT they do it once the helmets are already on the market. meaning the you could be buying a helemt before its even tested, to make matters worse they test in very very low numbers(reported as low as .004%, thats 4 out of 100,000!) and dont retest throughout production. BSI however is a prerelease test, meaning the BSI testing is done to helmets ready to be shipped, the test is performed on the helmets from that batch, and only certifications for that batch are given. Significantly more helmets are tested(5 for a production batch of 500, 13 for a batch of 501-1,200 and 20 for batches of 1,201-2000) no helemts reach the shelf without an earned certification, and the factory itself is inspected 4 times a year. This is BY FAR the most demanding certification procedure.
Again, no one standard is perfect, some are significantly better than others and hopefully a new standard in the very near future will combine the best of all for the safest helmets ever.
