Want to really make your head spin from too much information? Read this write up
on Snell M2010 from webBikeWorld.
I read it twice and still cannot completely comprehend the overall analysis. However, it seems to me that M2010 may be a bit lesser degree of protection on certain criteria than M2005.
From the write up:
For street riders in North America, the differences between M2010 and M2005 should be of little significance. M2010 does not exceed M2005 but it does demand comparable protection. But for street riders in Europe, M2010 may make a considerable difference.
Remember that motorcycle helmets must also meet local requirements (DOT in U.S.A., ECE 22-05 in Europe and the UK, etc.). The differences for European motorcyclists is that the Snell 2010 standard requires more impact management than ECE 22-05 and lower G force transmission for sizes 60 cm and up. Differences for North American motorcyclists include lower G forces transmitted but less impact management than Snell 2005 for sizes 59 cm and less. Snell 2010 still provides more impact management than the DOT standard, however.
Hmm. It does seem that M2010 was created so that the European helmets could come under the M2010 certification and so that all helmet mfgs could build a helmet that would meet all criteria (DOT, Snell and ECE) without having to make a separate model for Europeans. Probably a good thing for our Across-the-Pond riding brothers and especially good for the helmet mfgs.
But according to this article a US M2005 and a US M2010 are not much to sneeze at and aren't worth a nickel's difference. No need to not buy a M2005 just to spend 100$ more to get a M2010 certified helmet of the same mfg, style, etc...IMO!
More food for thought.