The story goes like this. We all know that dark colors absorb heat and light colors reflect it. But many proponents of black helmets claim that the 2 inch Styrofoam liner is a pretty darned good insulator. They say that if there was any difference, it would only be a factor at a standstill, that the moment you start moving, the wind will dissipate the heat. But I don’t go for subjective testing. As an Engineering tech, I need to see concrete data.

I think those would be reasonable considerations, if the temps were only a couple of degrees apart. And that is what I set out to prove or disprove. Take a look at this test and my conclusions at the end. I found the results to be very surprising.

Helmet Temperature Test
2012 Arai XC Ram helmets Diamond Black vs Aluminum Silver

Test conditions
89 degrees. Mostly Sunny. Wind Speed Negligible. All air vents open. Visors closed. Visors facing away from Sun. Air probes were placed between comfort liner and inner styrofoam shell.

Test Equipment

*Test error. I mistakenly inserted the probes in the sun, allowing the probe for the silver helmet to be exposed to direct sunlight for about 2 minutes, allowing it to heat up. The first 15 minute sample may have been tainted, and cannot be considered accurate.

** last 10 minutes of test were under cloud cover.

Conclusions.

The first sample had me scratching my head, until I realized the mistake I had made. But I knew that the temps would stabilize, and it would not affect the subsequent samples.

1. The test proves that it is indisputable that at a standstill, a black helmet not only gets hotter inside, but a lot hotter.
2. With a surface temperature 55 degrees above ambient temperature, the black helmet was obviously absorbing a massive amount of heat. The extremely high temperature of the black outer shell prevented the inside of the helmet from cooling down. While the inside of the silver helmet cooled down under cloud cover due to the lower external surface temperature, the inside of the black helmet continued to rise, even though the outer temperature dropped. Getting the helmet out of the sun did not provide any relief inside the helmet.
3. Even though this test was done at a standstill, I do not believe that hot 90 degree air flowing over a helmet at speed could have made much of a difference in reducing inside temperatures. Not only that, but on a Goldwing, not that much air hits the helmet.
4. I had hoped for continuous sun. But the presence of clouds at the end of the test turned out to be a blessing. It shows that once you stop, even for a short time, the temps rise so rapidly on the outer surface of a black helmet, that once you start moving, it can never recover.
5. The temperatures of both helmets reached their peak fairly rapidly, and then either stopped rising, or rose at a lower rate.
6. I was very surprised that the internal temperature of the Silver helmet only rose about 6 degrees above ambient temperature up to 45 minutes. I think this may prove that wearing a helmet is cooler than no helmet. I may go out in the Sun tomorrow and measure the temperature of my bare head after 15 minutes.
7.Those who believe their black helmets are not any hotter are kidding themselves.

I did not have time to make this a highly detailed experiment. But the results are so skewed that the limited samples provided all the data that was needed. I believe this is the only actual experiment that has been done on this subject. Everything else on the Internet is only opinions, which vary wildly. I think that my test now proves the answer definitively. I would like to put the probes inside the helmet and test the helmets while moving, but then I would not be able to return them.

EDIT: It also should be noted that with a human head in the helmet, those internal temperatures would have likely been higher for both helmets. Not only would there be less ambient air to keep the temps down, but our heads generate heat as well. The silver helmet would not have remained as cool as it appears in the test. But at the same time, the black helmet temps would have likely become unbearable. This test should not be construed as an example of what the actual temps are inside a helmet while riding, but rather looked at solely by the differences between the two helmets.

The Black helmet is being returned, and I am going to wait for the sliver one to arrive.

I hope this helps anyone considering a black helmet. FWIW, the Diamond Black Arai is gorgeous. I wish the results had been different.