No difference. The shell color is irrelevant since conductive heat transfer from the shell to the interior is practically zero due to the low thermal conductivity of the foam (it's basically a beer cooler). What makes a helmet hot/cool to wear is the degree of convective heat transfer (i.e. airflow) it allows.

While you could easily pick up a real aero lid at the expo, I'd stick with the "nothing new on raceday" wisdom and race the Kask.

---

ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

I was always under the same impression however Josh @ Silca made some very strong comments about this in one of the Marginal Gains Podcast episodes (I forget which one). He seemed quite sure that running a black helmet is making it way harder on yourself. Not sure what the data is to back that up but I suppose it really wouldn't be very hard to test and at least get some subjective evidence for or against. Anyone have a white and a black aerohead they want to do some experiments with?

---

Benjamin Deal - Professional - Instagram - TriRig - Lodi Cyclery
Deals on Wheels - Results, schedule, videos, sponsors

Bedouins wear black in the desert.
It's not the color, its the ventilation (loose fitting, layers)
with helmets, it's the ventilation not the color.
number/shape of the holes, speed of the rider.
wearing a cabbage leaf on your head keeps you cooler than going bare headed. But its not very aero

---

Anne Barnes
ABBikefit, Ltd
FIST/SICI/FIST DOWN DEEP
X/Y Coordinator
abbikefit@gmail.com

https://www.youtube.com/watch?v=4SpHqtGPlJA : Ref to actual testing from helmet mfg.

---

ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

I've been racing in my black Bambino for a few years. Hottest I raced in was around 105F. It felt warm and a bit uncomfortable, but not terrible. And that was probably down to ventilation rather than the colour. I was expecting to cook, but it didn't end up that way.

https://overcast.fm/+QSf7ehlIA Somewhere in this one I believe. I heard it over the weekend and was shocked. I thought it mattered for things close to the skin such as clothes but not helmets due to the foam?

I did a little experiment with a black and a white helmets Aeroheads

95 degrees and sunny.

Placed them in the sun with a thermometer under each for 1 hour

Then reversed the thermometers to make sure they were accurate

I thought for sure the white one would be cooler

Nope they were the same temp

I think the main take-away here is that it is clearly time to start racing in cabbage leaves when its hot out! Who cares how aero you are if its comfy!

Alternatively, someone has to take a cabbage leave to the wind tunnel to see just how many watts we would lose out on (to see if it could be worth it!)

Anne is right that it's all about ventilation. Bedouins can/do wear black because it allows less light penetration to the skin for a given weight and breathability of fabric, and for lightweight fabrics the amount of additional heat it can hold compared to white is negligible.

For road helmets this is the same story.. it's all about the ventilation and while you might be able to find a small temperature difference on the outer surface of the helmet, you can't see anything inside the helmet as that temperature is purely driven by airflow.

Low ventilation aero helmets, however, are not the same story. In my previous life I was part of a team test where we measured 2-5 degrees C difference between aero helmets with white/shiny finishes and matte black ones. While this isn't the end of the world, it can most certainly be a factor over time.

---

http://www.SILCA.cc
Check out my podcast, inside stories from more than 20 years of product and tech innovation from inside the Pro Peloton and Pro Triathlon worlds!
http://www.marginalgainspodcast.cc

Wow. 5C is a lot. Even with the low ventilation, given the theta of foam...that's still surprising.

Josh, thanks for the insight. Can you provide some additional details on the test protocol? Examples: what kind of helmets, how/where were measurements taken, environmental factors, etc.

---

ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)