Did the extreme 3d printed aero pieces on that guys bike at lahti thread not cause enough arguing over the rules mayhem for you?
/pink

You don't really have to justify why you're putting this in your jersey under current triathlon rules. You're not allowed to put this in under UCI rules. Put it in, proudly tell everyone it's for aero and go a little bit faster.

I thought it may be faster than a bottle or camelback, with no weight and easier to run around transition, plus is has the rain jacket effect (at least for front), in the cold. Breathability may be poor in ultra hot, but I thought of it on a cold day, when my jersey was not really "smooth" because the plastic was somewhat crumpled up and I realized that maybe that is a good thing aero wise.

Only way to know if it's faster is to test it. Generally, the bigger the chest thing is the better it will be. If breathability becomes a limiter then just dump it at an aid station.

Tbf tho, if you're getting a 'rain jacket effect' on your chest then you're probably too upright for such aero devices to be of importance.

As long as you do not put it in during the swim :-)

 

You can market it as: My Air Pillow!

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Once, I was fast. But I got over it.

And forever be known as Dev, the My Air Pillow guy

Why not just go with a heavier-duty latex balloon? If the aim is to prevent airflow to the area between the chest and arms, wouldn't it be better to get a large balloon, blow it up halfway (or however much you need so) and have it completely fill the cavity open between the chest and arms.

I opted for a bottle due to durability, but if you're going with something inflatable, why not pick something that conforms better?

I wouldn't put too much thought into this. It will likely be illegal to do within the next year.

Not only does it add another unneeded/unwanted complexity to the sport, it also makes triathletes appear even more "Jerry/Carl"-esk. Non-purpose serving fairings on the bike are illegal in IM and USAT already. (although people violate this left and right) There will likely be a blurb added to the rules in the future about how trisuits/garments need to be form fitted to the wearer.

TLDR: It looks ridiculous and offers too much of an advantage over those unattuned to the benefits. Let's keep bikes looking like bikes and riders looking like riders.

I wonder why 90% of the male Pros in Lathi didnt use this trick?? 🤔