gater said:
The Shoei helmet fits people with slim heads. The Arai fits people with round heads. That has been my experience.
Well, due respect, that's contrary to the conventional wisdom and my experience. You're correct in that folks used to say you either had a "Shoei head" or an "Arai head," with the shapes being the other way around. I've got a very round head. I could wear the Arai Quantum and old RX7-RR4, but not the newer Corsair. With the exception of a couple models that mashed the crap out of my ears, I've always been able to wear a Shoei. Right now I have an RF1000 and a Multitec. Both of those run about 1/2-3/4 size large, BTW.
If you go to the Arai site, they describe the three shapes they make as long, intermediate and round oval. My round head takes the round oval. The traditional Shoei shape is this round oval, perhaps somewhat less round than the Quantum, but certainly more round than the Arai Profile.
Shoei's three current full face helmets are the X-Twelve, RF-1100 (there are plenty of RF-1000s out there at great prices, since that model has been discontinued), and the Qwest.
A simple explanation is that the X model has largely been marketed as the full-on race helmet, typically tighter fitting and less plush perhaps than the RFs, and more expensive.
The RF is the big seller, offering the most in terms of features and comfort, at the middle price point.
They used to have a third level, which included the TZ-R, Z-Two, and TZ-1. Beats me when those went out. If you look into those, make sure you check manufacture date before you buy.
The Qwest is their new line, which seems to be at a slightly lower price point than the RF-1100, and aimed at touring or sport-touring riders, with the selling point of being quiet. I have no experience with that one-haven't even laid hands on one.
Back to the original question of the thread, I find the RF-1000 to be pretty quiet, as is the Multitec. Both are incrementally quieter than the Arai I retired in 2009.
Long winded, but HTH.