Giro Aerohead faster without visor?


Yesterday I did some aero testing and found that the on me the aerohead is a tat bit faster without the visor. The difference is about .01 to .02 cda between tests at race pace(315 watts) and similarly at sub threshold efforts(200 watts). I found it by accident while riding back to my car after a run. I had put the visor upside down on the helmet and looked down to my wahoo and saw some lower numbers then the runs before that so a did some speed runs with it and got these results.

Have any of you guys found the same?

I think there’s arguments on this subject and I do think there’s data out there that the visors make no difference or even are a little slower.

How were you measuring cda? Also assuming you flipped your race pace and Supra threshold numbers?

Curious to know how you are testing that with such precision but I read that helmet is faster without the visor. If you need sun and wind protection I think you just have to deal with it though. If you wear sunglasses in place of the visor, I imagine aerodynamics would be worse than the visor due to the shape

Yea I heard the whole visor argument and that is why I asked here if anyone found the same with the Aerohead. How I measured is maybe a bit crude but it gives some data.
I ride on a 2 Km concrete forest cycling path during low wind so there is pretty much no wind on the course. I do 4 runs 2 out and 2 back. I pres lap when I’m up to speed and do a ±1500 meter run. I put those values in a excel sheet I made and average the 4 runs. No visor was faster 3 out of the for runs and one run it was the same as the lowest run with visor. Both deltas being .015

PS. sup is supposed to be sub. My bad. Dyslexia :sweat_smile:

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Interesting. I have the same helmet. My ftp is similar - 305 now and peak of 320 last year. I’ve been meaning to try and do some similar test runs like that as I love geeking out on aero stuff. If I’m able to try it I’ll get back to you with the results.

I have some upcoming tris and I was wondering if it would be better to go visorless just for some extra cooling. Plus the visor is a little weird how it sounds and feels.

The cooling part is a good one since that is my biggest problem whilst time trialing.
Aka more testing is needed. I would love to see you results.

I’ll do my best in the next few months. I have a good spot to do similar to what you do right next to my house - flat and straight wooded section. I got lots of work to do on my new winter bike build before I get into the details of visor vs none. But I’ll let you know if I get it done.

Based on cycling weekly review, taping the vents would give a measurable gain.

So if removing the visor is indeed faster, the cooling advantage could be used to cope with the added heat from covering those cooling channels.

This would be the fastest configuration for this helmet.

If he rode with the visor in the “up” configuration, could it be that he inadvertently plugged the vents? Perhaps its worthwhile comparing plugged vents w/wo the visor to eliminate the variability.

I retested a few weeks ago but it seems the be very position depend. When you can keep your head down looking at your computer it is faster without the visor. For me at least. But on a more corner heavy heads-up course it’s slower. Getting enough time on my test course is hard since it’s a course held by a local racing club/team. It’s a short corner heavy track so testing heads down isn’t really an option and speeds do not go over 40 km/h for I do not have the balls to do so. I’ll try to get a better heads down test track on a local forest road. In a two weeks I’ll retest again and tweek my position. I am tall enough to be in an extraordinary position. New parts are coming.