Davinci..

I'd like some opinions on the pros and cons of the giro ionos and giro atmos helemts.
I'll start by pointing out i absolutely loath the idea of spending over $100 on what is basically a piece of Styrofoam. However anyone living in the north east this year, knows how ridiculously hot its been this summer. With the humidity, its commonly hitting 38-40 degrees C.

Until now, ive been perfectly content with my $45 specialized chamonix. Light, cheap, snell rated, and fit me perfectly. Only issue, its not particularly well ventilated, with only a smattering of small/medium sized vents, it is simply inadequate in anything above 30 degrees, and un-rideable at 35, as its been all summer.

I sweat like a champ, so im willing to bite the bullet for comfort, and rideability(read; proper cooling, ventilation). Online, the Atmos and Ionos differ in price by around $30-$35, and while i already hate the idea of spending so much on a helmet, if its actually worth it, ill pony up. So is the ionos that much better then the atmos? $30 better??
The atmos already seems like a pretty good helmet, yet Giro claims substantial increase in airflow in the ionos, the atmos's ventilation looks great to begin with. The ionos is also "said" to be substantially quieter, but is heavier, more bulky on top of you head. Anyone with some personal experience with the 2?, is the atmos sufficient? or is the extra $30 worth it? and make that much of a difference?

Thanks your for input

umd

The atmos and ionos fit completely differently. Try them both and see which one your head likes better.

tobycat

I've used them both but now I really like the new Pro Light better than both of those.

phoenix

Had an Atmos, and lucky for me I had it on and cracked it instead of my head. After that I bought an Ionos. For me, the biggest difference was the overall size of the helmet. Both are a size L if I recall correctly. The Atmos sat a little lower so it had a lower profile and seemed not quite as wide as the Ionos. The Ionos looks a little larger on me even though it is the same size as the Atmos. As far as comfort, ventilation and weight, I didn’t notice any difference between the two. Both are an very comfortable, light and breath very well. I would still recommend trying them both on to see what you think.

derek.fulmer

I own the Ionos and as far as comfort goes, it's great. I have a size large. I haven't had it out yet since my bike isn't in, but it's comfortable on my head. So far so good. Mine also came with a free pair of Giro sunglasses with interchangeable lenses.

bostongarden

So true.

jonathanrules

had both; currently have the ionos

atmos; smaller; more narrow; very comfortable
ionos; a bit larger; wider; more mushroom looking; very comfortable; VERY ventilated

in my opinion you can't go wrong with either

hammond9705

I have both also, and as mentioned they are both very nice. Nobody has mentioned the winter liner that the Ionos has, which I like. You remove the velcro pads from inside the helmet, and replace them with a sort of half cap. It doesn't look like much, but does help in the winter cover some of those vents that are so nice in the summer.

R900

I have both, the Ionos is more comfortable, and maybe slightly better ventilated. However, it's been so hot lately I don't think any high end helmet can keep cool in the heat.

teterider

Did you notice in the Tour this year, that on any hot day almost everyone wore their Ionos instead of their Prolight. The Prolight is light, but as every reviewer has said it just doesn't have as much venting.

2ndGen

1+ for the Prolight.

But to answer the OP, what "umd" said.

2ndGen

Almost everybody except the winner.

Eclectus

I drank the Kool Aid and got an Ionos. I like it, but I think my cheap Bell Variant was probably close to as good. The fact is, in really hot weather, sweat is going to drip into your eyes. You can go for Super Kool Aid and get a Catlike Whisper Plus. (You can wear a Halo headband too, which helps, albeit imperfectly.)

No helmet may be best for head-cooling when it is really hot. I've tried it, and it works. You have to decide what you think the risk/benefit ratio is of not wearing a helmet.

If you wear a helmet, white may be the best at sunlight-heat reflection. I have no scientific data on this, but it's intuitively sensible, being more reflective than colors. Maybe silver would be even better.

998

The Ionos probably provides a touch more ventilation. However, I wore a pnuemo here in Texas for years. And trust me ventilation is crucial here, the heat index is 110 right now. The pneumo has less ventilation than the Atmos and the Ionos so I wouldn't be overly worried about the ventilation issue. Both the Atmos and the Ionos should provide plenty of ventilation. The Ionos is light for sure but I don't supect it is noticably lighter than the Atmos. See if you can find a place to try them on, go with the one that fits you. I went with an Ionos, I got a great deal on one. Atmos would have been sufficient.

colombo357

Get the Ionos, it'll make you faster. That's why pros use it.

ahsposo 

I ride in south Georgia heat and have a Saros and and older Giro Monza. Haven't put either of these to the test but I have broken three other Giros. All were middle of the line and worked fine, I guess.

Like the OP noted I can't see spending a lot of dough on styrofoam but I need the helmet to ventilate and absorb sweat. The Saros does both just fine.