Coast Down in aero position or on bars?

[JR_70]

Just have a question regarding coast downs. As a triathlete - I know that I should be riding aero as much as possible - however, as an Ironman athlete - it is rare that I would ride in the aero position for an entire race. And more often than not - my training is done from anywhere between 10-50% of the time in the aero position.

Therefore - should my coast downs be done in the aero position or sitting upright on the bars?

Cheers!

JR

PS - Wasn't sure where best to post this question - so I posted it in the TT section as well...

[racerfern]

If you want to be able to separate the two positions then do your coastdowns in you most aero position. There is a function in the iB3 software to raise CdA if under a certain speed but not vice versa.

There have also been discussions on some forums that your aero position tends to yield about the same wattage as your non aero position because you have less mechanical advantage with your upper body. IOW, fewer watts go to fighting the wind but you make fewer watts.

When push comes to shove I don't think it makes a huge difference. That said, if you're looking for a way to save 5 watts then you need to really do coastdowns in each position and some test runs to really nail it. Your goal isn't to be able to create as many watts as possible, your goal is to use as few watts as possible.

I do have to suggest a remote wind sensor because your body over the iBike will change your wind scaling and skew the power numbers more than just the affect of an aerodynamic change.

[JR_70]

Thanks so much. I appreciate the response. I do have the remote sensor and it works awesome. Very easy to "clean up" the front end and still place the "funnel" in open air space. Great little device.

I am not overly concerned about small differences - just wanted to make sure I wasn't going to get really off data if not in one position or the other. Thanks again - aero position coast downs it is ....

[rruff]

Therefore - should my coast downs be done in the aero position or sitting upright on the bars?

I would do a set of CDs and Cal Ride in both positions. It will effect not only your CdA but your Wind Scaling as well.

[coachboyd]

I would definitely work more on consistent riding in the aero bars. You will adapt to the position and get to be comfortable on them. If you can ride the entire event in the aero bars and be comfortable at the same time, you will be much faster. Just tell yourself every time you get out of the aero bars "There goes five seconds"

I have a pretty radical position on my time trial bike, needless to say it's not comfortable. . .but I also don't have to run afterwards and all of my time trials are under an hour in length. But in the winter time when I am building my base, I like to go on long rides and stay in the aero position no matter what. Even going up some of the big climbs around here I try to stay in those bars, it really makes a difference in the long run.