Should wind be zero on circuits or out-and-backs?

[MultiRider]

Should the average wind be zero on a circuit course? I did a crit and didn't get my wind zeroed before the start of the race. Warmed up on the trainer, went to the starting line, race, never did a wind offset. When I go into the iBike software, it shows a 3.5mph head wind. Since we were racing a 1.6 mile circuit and did lap after lap on the same roads, should the wind be zeroed out?

Same question for an out-and-back. I've done a couple time trials where I made the same mistake -- warmed up on the trainer, did the race, then realized I never zeroed the wind. Should I use the software to zero it out?

It showed a head wind in each scenario, so when I zero wind, my power numbers go down. Which is disappointing. But if those are the real numbers, I need to know.

Thanks.

[rruff]

A 3.5 mph net wind is a lot... especially when you consider that you should be drafting a lot in a crit and the wind should be negative. So no... zeroing it after the fact doesn't really make sense in that situation. For an out-back TT with no drafting it would make sense... so long as it is close to zero anyway, and you know your wind scaling is good.

But... I'd look more closely at your calibration and see if something is off. When was the last time you checked your wind scaling?

[MultiRider]

I double-checked and apparently mis-remembered. The iBike "Analyze Wind" function reveals a 1.9mph headwind for the crit. I am a beginning crit racer, not used to riding/racing in packs, and spent most of my time on the edge of the pack or the back of the pack. I got some of the aero benefits of being in the pack, but not a lot.

The "Analyze Wind" for the TT shows a tailwind of 7.5mph (Avg Ground Wind of -7.5mph in iBike 3 software). It was basically a lollipop type course -- out approx 3 miles, 4 mile loop, return on the original 3 mile road. I haven't created a TT profile yet -- I just borrowed some clip-ons and a fast-forward seat post and went racing.

I'm not sure what "check your wind scaling" would entail. My profile has an aero of 0.450, fric of 8.800, weight of 205, wind scaling 1.421, riding tilt of -0.4, CdA of 0.317, and Crr of 0.0056.

How would I check the wind scaling value?

[rruff]

How would I check the wind scaling value?

http://www.ibikeforum.com/viewtopic.php?f=6&t=867

Aero bars will seriously effect your profile... a -7.5mph wind is huge! Unfortunately you don't know what your CdA was either with the aerobars, so getting an accurate power value for that ride would not be possible.

Having a positive wind for the crit doesn't make sense either, so definitely check your calibration.

[coachboyd]

Yeah, if you have a 7.5 mph tailwind for a time trial then it sounds to me as if your hands could be blocking the wind port a bit when in the aero bars. The Remote wind sensor has been shipping now and I can speak from experience that it works great.

If you have a solo ride on your road bike (the one you did the crit with) I can check your wind scaling as long as the ride started and ended at the same place.