Questions about Coast Downs

[aytchkay]

I bought a new bike and went thru the process of setting up a new Profile for the new bike.

I forgot that the Coast Downs are supposed to be AFTER the Calibration Ride so I did the Coast Downs first. That was mistake #1.
I did 8 C-D's but did them in each direction instead of going back to where the first one started. In other words, I went South with a bit of tailwind and then back North with a bit of headwind, then repeated this 4 times. Mistake #2!

So I would like to know if this data will be accurate!
For instance, do I use ALL the C-D's to create this Profile, OR should I use ONLY the Coast Downs done in the same direction? I looked at the Profile 3 ways: All C-D's, odd-number C-D's and even-number C-D's, each had different coefficients. And which would be the most "accurate"?

Which Profile data should I use? Also, does it really matter that I did the Coast Downs BEFORE the Cal Ride (which was 2 miles each way)?

Can someone help me with this?

thanks!

[Velocomp]

About 99% of our customers no longer do coast downs. The "Fast Start" sequence does an extremely good job of providing accurate CdA and Crr information.

If you decide to do coast downs, it is very important to follow the instructions exactly.

I would not use ANY of the coast downs you did, because the Cal Ride was not done first.

Do the cal ride first, then the coast downs immediately thereafter. Also, I would do the coast downs in the same direction, into the head wind (though the instructions say that winds should be light).

Or, skip all of the above and just do the Fast Start sequence, then a Cal Ride

[aytchkay]

Thanks John!

I will do exactly that!!

aytchkay
aka howard

[GrittyGoober]

YES!

I just got a new mount and was dreading re-calibrating my iBike since I had a profile that has worked well for me. The coast downs always gave me headaches. I screwed up more profiles than I want to admit .

It is good to read coast downs aren't really necessary any longer. That is what I was hoping to find before I go out and re-calibrate.

Thank you Velocomp! This is really great news.