Ok, so I can get the Chrono for about 65 bucks and the Rocket for 125. I’m an average AGer not a top tier guy by any means. My avg bike speed is 18. I will be doing an Ironman this year and think that the helmet might give me some time over that distance. So here are my questions:
(1) Do you think a tt helmet is a wise purchase for me?
(2) Which one is a better bang for the buck?
Thanks for your thoughts.
You’ll save more time per $$ on the chrono, that much I’m sure.
Even the worst aero helmet is 4/5th as good as the best aero helmet, in terms of time savings compared to wearing a road helmet. Tested in the MIT wind tunnel.
The rocket is a better helmet, but how good a helmet do you want?
Ok, so I can get the Chrono for about 65 bucks and the Rocket for 125. I’m an average AGer not a top tier guy by any means. My avg bike speed is 18. I will be doing an Ironman this year and think that the helmet might give me some time over that distance. So here are my questions:
(1) Do you think a tt helmet is a wise purchase for me?
(2) Which one is a better bang for the buck?
Thanks for your thoughts.
IIRC, I measured an approximate difference of .010 m^2 of CdA between the Rocket and the Chrono for MY position. Assuming that this works the same for YOUR position, the choice is if it is worth it to YOU to spend an extra $60 for ~ 1 sec per km of time gain.
I bought the Chrono. I also did not like the idea of covering my ears when I ride. David K
I also did not like the idea of ears being covered, both for ventilation and hearing. It also looked like the Chrono is lighter and has more vents. Do you notice time savings with it?
I bought the Chrono, mainly cause I don’t want to cover my ears and overheat. It is also lighter for hilly courses, and when I have my head down, I it is still a pretty smooth line from my head to upper back without sending the tail straight up into the air.
Finally, when I wear it around the city at an out of town race, I don’t look like a total dork riding at 25 kph as I spin my leg out and check my gears out as grandmothers riding upright with baskets filled with their Saturday morning groceries pass me 
Dev
Out of curiosity, is there a speed at which you are just too damn slow to get any benefit from an aero helmet? I saw an amazing number of people at Lake Placid riding 7-8 hour bike splits wearing aero helmets (and many with disk wheels). Aside from the fact that they look silly riding 14 mph with those things on are they just wasting their money?
If they really wanted to get a good time, they should have also considered running with them on, too.
The truth is that tecnically, they give benefit until their weight outweighs the aerodynamics. But in terms of making much of a difference… not so much.
where do you get the crono for $65?
…when I have my head down, I it is still a pretty smooth line from my head to upper back without sending the tail straight up into the air…
Actually, I’ve found that due to the “curve” in the Rocket tail, this is much less of an issue than with, say, the Prologue or other aero helmets.
BTW, I wore my Rocket WITH the faceshield (cuts some of the airflow) in two ~40K TTs this year in the desert (temps above 80 for both) and “overheating” wasn’t an issue for me in either. I was wearing a long-sleeved, dark colored skinsuit in both as well…YMMV 
Amazon 89.99 - ($25 rewards points card) + free shipping from seller. I got it last night. I’m glad I did. Although now my wife is hesitant to appear next to me at races b/c she thinks the helmet looks silly. I don’t necessarily disagree, but if it will get me off of that IM back even just minutes faster, I’m for it. Nashbar is also selling it for 89.99 and had a 20% off coupon yesterday, so that’d be a decent price too.
Rocket
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So why did you post on here which helmet to go with if you already had made up your mine and already had ordered it and went with the Chrono? I have to agree with your wife that the Chrono does look silly.
Amazon 89.99 - ($25 rewards points card) + free shipping from seller. **I got it last night. **I’m glad I did. Although now my wife is hesitant to appear next to me at races b/c she thinks the helmet looks silly. I don’t necessarily disagree, but if it will get me off of that IM back even just minutes faster, I’m for it. Nashbar is also selling it for 89.99 and had a 20% off coupon yesterday, so that’d be a decent price too.
So what Amazon service did you use? Instant delivery? What a schmuck, asking for advice on a purchase he already made. Why waste people’s time and good intentions if you already bought it?
I posted before I bought it and after I received as much feedback as I could before I had to go to sleep last night.
Wow, what got up your ass? I posted this before I purchased the helmet you piece of … Before you go calling people names, why don’t you think for just a minute (or longer if you need it, which seems to be the case). By “got it”, I don’t mean received it, I mean purchased it.
Don’t worry about it, some people are just idiots and can’t be bothered to read the time on the posts.
FWIW My aero test data was similar to Tom’s, roughly 5W or so at 20mph. Both the Chrono and Rocket were a decent improvement over a plain Giro Eclipse helmet.
…By “got it”, I don’t mean received it, I mean purchased it.
So great, making your own definitions as you post.
And from the Merriam-Webster dictionary: “1 a : to gain possession of”
So maybe in your case, you should wait a minute or longer and reread your posts and make sure they are accurate. Jack London wrote in one of his books: “If you palter with the truth in such little matters you may darken your more important statements with suspicion.”
“Pedant ('pednt): a person who is excessively concerned with minor details and rules or with displaying academic learning”
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I got a 2007 model Rocket because it has more vents then the previous models did. I have done the Tupper Lake half iron distance in it (June N.Y. State) and The New York City Oly Tri (July) and was very pleased in that I did not get over heated from it. I haven’t gotten a faceshield because I thought it might be to hot. What color(s) do you have and are they scratched easily? Do you have an opinion as to if it makes the set up any faster? Tim