I've heard 8% watt reduction. I know that it must vary pretty significantly depending on the helmet and riding position. Since you're doing half ironman, a couple minutes sounds pretty reasonable.

The MIT cycling club does wind tunnel testing for their time trial runs, and their results show that in terms of drag reduction per dollar an aero helmet is a much better buy than disk wheels. I don't remember the exact watt reduction number, but I think it was <~10%. I recently got an aero helmet for this reason, and although I've only ridden it twice I can already tell it's not as dramatic a speed increase as the difference between aero bars and sitting upright. Then again, I'm using the Louis Garneau Prologue, which is probably not as aero as the Rocket or any of the other top tier aero helmets.

You will get more of a time savings from an aero helment than from aero wheels (assuming the wheels you do have are of high quality of course).

Buy the helmet first and then wheels if you have money left over.

I second RV's question. The data are increasingly clear that the time savings from these helmets compare favorably to $$$ race wheels at literally a small fraction of the price.

I've been looking at the Giro Advantage 2 and the LG Rocket online, but can't seem to find a retailer in the area who is stocking these.

I have an LG Rocket and I really like it... it is comfortable, and I didn't think it felt more warm than my other helmet despite claims that the lack of vents is a big issue (and I think they are adding vents in the next model -- I've used the 07 and the 08 I think).

Just be sure to get the right size -- with my hair loose we thought a medium would be ok (and nice to have one size helmet fit both Mike and me) but then I did a test ride in Mike's to make sure, and with my hair back it was a bit too loose. To get it tightened down enough to fit well the helmet put too much pressure in my forehead and gave me a headache. With the small I now have I didn't have any issues getting it to fit comfortably.

My spiuk make me happy! I'm not sure that it actually makes me faster since I'm slow at biking, but it definitely makes me look like a dork!

Yay me too! :) And the best part is not the dorking on race day... but on the bike path around home testing it!

My wife told me should would rather me be slower than look dorky...

The way I see it, we're already out there racing in lycra shorts (or, shudder, a Speedo) and a skin-tight tank top, possibly with shaved legs, and with an aero bottle and a bento box.

We crossed the city limits into Dorkville a long time ago, so we may as well ride a little faster while we're there. :D

Depends on who you ask. Just a guess--I think roadies would agree with you, while the non-racing public would think the helmet was worse. We just can't win. :)

Fastest dork wins!

So is that how we're going to recognize fellow trifuelers in the future? Our new slogan? :D

Now I'm very afraid of where that slogan will be.

Leave it to you all to sum it up perfectly... I just bought an aero helmet today and did a search to see what experiences people have had with them and turned up this thread!

I've got a HIM this weekend and the aero helmet is looking appealing if for no other reason than that it covers my ears (it should be about 47 degrees and raining when we hit the bike course). But you can't discount the dorkiness factor, and I have to admit, it's a bit intimidating to overcome that and put the stupid thing on!

They were all over the bike course at Ironman Wisconsin this year too--I'd estimate around 15% of the field had them.

i dunno...i still have this feeling that you need to earn the right to wear an aero helmet (either by going fast enough or having put in the time, like IM)

...that dork factor is pretty high, the closer you are to slowpoke...sort of a logarythmic scale

I am getting the Spiuk Kronos for christmas this year, hopefully. My g/f is the best. She basically asks me what I want, so I make a huge list of tri stuff, and then she gets me some stuff from the list. My Christmas list is going to be Spiuk Kronos, Spiuk Kronos, Spiuk Kronos, etc...

Yeah, and safer! You never know how forum sessions will go ;)

Just picked up my aero helmet brand spanking new Spiuk Kronos for $120 (that included the bike fit I originally went in the store for lol). I may be a dork but I'm a fiscally savvy dork lol!

Here's my new goofy hat. Guess I'll find out on Saturday if it makes any time difference. At least it will keep my ears warm!

Had to revive this thread.