Posted: Mon Oct 06, 2008 11:33 pm
I just got back from a night ride this evening on the V-strom. What a killer helmet the HJC AC-12 carbon is! This helmet is the best thing ever. When I left a friends house I picked up the helmet to walk out the door and it surprised me again how light it is. The wind noise was very low since I was behind the V-strom windscreen. I like to basically break down the helmet noise into two categories: 
The HCJ carbon had less low frequency noise as it covers your neck a little lower than the Shark RSI thus producing less wind turbulence. But it has more higher frequency wind noise from the number of vents that it has compared to the Shark RSI which only has a couple. In the next coupe days I'll take the HJC out on the Aprilia to get the whole helmet out in the wind so see how it sounds on a sportbike. The light weight is becoming more of an advantage than I thought it would be. Turning your head side to side with the HJC is effortless. I'm not sure if that's because of the aerodynamics of the helmet or solely due to the light weight. When I jump on the Aprilia with it I'll find out pretty quickly. One last note, my ears were most comfortable in the HJC AC-12. There is a lot of room in there for the ears. Wearing earplugs will easily be the most pleasurable in the HJC. I don't think I'll have much of a problem not wearing plugs with the HJC and the Shark is so quiet anyways. The Arai RX-7 almost requires them when you wear it.

I actually could feel the air being pulled out of the rear diffuser / exhuast vents back there. I tested it out by closing off the front vents, standing up and looking down a little. This seemed to cause air to pull out pretty good. I will be trying this with the Arai to see if I can get the same effect. I've never felt the air pull out like that out of the Arai before but I'll try again the same way. With factors like the chin bar being further away from my face then any other helmets I've tried, the amount of air being push/pulled through this helmet and the included breath guard... I can't forsee the (anti-fog) face shield fogging up ever. It's been pretty impressive so far.
**UPDATE notes from November: This HJC is really really comfortable and vents air like crazy. I was surprised when I got up to sporty speed how much air was going through. I'm just really bummed because the Large is just a little too big to ride at fast speeds. A medium hurts to take on and off my head but fits perfectly once on. I don't want to wait for a medium to break in so I'll just use this Large for cruisin around and not for high speed stuff. If anyone finds that this helmet fits their head pretty good and it doesn't hurt to take on and off go for it... this is a GREAT helmet and can be found at compacc.com for $260 with free shipping and no tax. The sheilds are really inexpensive as well which is awesome. Mine hasn't fogged up one bit. Ok END NOTES, thanks for reading.
I also got a deal recently on a Medium Shark RSR2 helmet which I can't wait to try out. I'll be sure to talk about that one when it arrives as well. I'm predicting that the Medium size will fit just as good as the RSI model and be perfect for more high speed situations than the HJC AC-12. If the HJC Large size was a tiny bit smaller it would be a better fit on me. But at this point the Arai RX-7 Medium fits on me the best and is more stable on my head at speed. We'll see how the RSR2 does against the RX-7.
- 1.The high speed swishing you can hear over the smaller vents or recesses in the mid and upper parts of the helmet.
- 2. Then I can differentiate another type of noise which is the lower frequency waffs of noise that come from the lower opening of the helmet near your neck.

The HCJ carbon had less low frequency noise as it covers your neck a little lower than the Shark RSI thus producing less wind turbulence. But it has more higher frequency wind noise from the number of vents that it has compared to the Shark RSI which only has a couple. In the next coupe days I'll take the HJC out on the Aprilia to get the whole helmet out in the wind so see how it sounds on a sportbike. The light weight is becoming more of an advantage than I thought it would be. Turning your head side to side with the HJC is effortless. I'm not sure if that's because of the aerodynamics of the helmet or solely due to the light weight. When I jump on the Aprilia with it I'll find out pretty quickly. One last note, my ears were most comfortable in the HJC AC-12. There is a lot of room in there for the ears. Wearing earplugs will easily be the most pleasurable in the HJC. I don't think I'll have much of a problem not wearing plugs with the HJC and the Shark is so quiet anyways. The Arai RX-7 almost requires them when you wear it.

I actually could feel the air being pulled out of the rear diffuser / exhuast vents back there. I tested it out by closing off the front vents, standing up and looking down a little. This seemed to cause air to pull out pretty good. I will be trying this with the Arai to see if I can get the same effect. I've never felt the air pull out like that out of the Arai before but I'll try again the same way. With factors like the chin bar being further away from my face then any other helmets I've tried, the amount of air being push/pulled through this helmet and the included breath guard... I can't forsee the (anti-fog) face shield fogging up ever. It's been pretty impressive so far.
**UPDATE notes from November: This HJC is really really comfortable and vents air like crazy. I was surprised when I got up to sporty speed how much air was going through. I'm just really bummed because the Large is just a little too big to ride at fast speeds. A medium hurts to take on and off my head but fits perfectly once on. I don't want to wait for a medium to break in so I'll just use this Large for cruisin around and not for high speed stuff. If anyone finds that this helmet fits their head pretty good and it doesn't hurt to take on and off go for it... this is a GREAT helmet and can be found at compacc.com for $260 with free shipping and no tax. The sheilds are really inexpensive as well which is awesome. Mine hasn't fogged up one bit. Ok END NOTES, thanks for reading.
I also got a deal recently on a Medium Shark RSR2 helmet which I can't wait to try out. I'll be sure to talk about that one when it arrives as well. I'm predicting that the Medium size will fit just as good as the RSI model and be perfect for more high speed situations than the HJC AC-12. If the HJC Large size was a tiny bit smaller it would be a better fit on me. But at this point the Arai RX-7 Medium fits on me the best and is more stable on my head at speed. We'll see how the RSR2 does against the RX-7.











