Adjusting Newton for other aero factors for race

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blueraidermike
Posts: 19
Joined: Tue Oct 04, 2011 8:38 am

Adjusting Newton for other aero factors for race

Post by blueraidermike »

Have a question. I have my ibike dialed in with my power numbers in training. I am doing a half ironman race in two weeks. I will be adding an aero helmet and a disc for the race...how do I adjust my settings to have the watts read accurately? This is the first time I have ever raced with power as a guide.

I would appreciate any suggestions, opinions.
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Russ
Posts: 370
Joined: Sun Feb 10, 2008 4:08 pm

Re: Adjusting Newton for other aero factors for race

Post by Russ »

blueraidermike,

The most accurate way is to do cal ride with coastdowns with that equipment to develop a matching profile.

A couple of short cut ways to get (how?) close would be:

1. Assuming you are using same tires and pressures for should be same Crr, do a few runs down a hill and analyze the Cda displayed while coasting. I would do it with current equipment several times and with the race equipment several times to average results and then manually tweek a custom profile. It is probably less work to do the cal ride : -) Of course no wind or stable wind conditions are desired.

2. Look online for other riders or research values for two positions and wing a manual tweek of a custom profile (least physical work and perhaps the fastest but probably least accurate).

Regards,
Russ
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racerfern
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Joined: Fri Jan 11, 2008 12:47 am
Location: Baldwin, NY
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Re: Adjusting Newton for other aero factors for race

Post by racerfern »

Crr might change if the disc setup also has a tubular and the regular setup is a clincher. Compare the race setup with your everyday setup on the same bike. You can always post your profile which might give some clues.
Fernando
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