Wind cal ?

[GWPOS]

I was under the impression that we were not going to have to do wind cals anymore. I finally got my profile pretty spot on and did my FTP test on Sat. I put the unit on my bike and went out to do my FTP test after riding for about 15 min or so. I did a wind cal just before leaving my garage with the doors closed, even though we are not supposed to have to. I do this because these all out FTP test are important to me and I just wanted everything to be ok.

Now back to the test. It was miserable. I was very well rested but my numbers wre so low that I kept pushing harder to get them up were I know they should be. Like I said did not go so well, I finally ended up almost stopping after 15 min(actually did fo 20 sec) but then decided to finish it up. My numbers were like 40+ watts lower than my last test. I thought that it had gone down by maybe 10 watts but not 40+.

I went home and downloaded my ride. I then checked my wind scaling it is was sitting up in the +/- 5's. Can not remember which one. I then did a ride reset and went out just to do some easy riding. Before leaving I did another wind cal and then took off.

Now after taking some time to look at my FTP test file I noticed that there was a 5 mph difference in wind and wheel speed. There was no wind this entire morning at all. My second ride file for the day had almost totally identical wind and wheel speeds. Only differnt by .1 or maybe.2

I am not asking anyone to look at ride files or anything, just trying to figure out why I have to do what we were told we would not have to do any more in regard to doing wind cals. Or am I just missing something?

[bjrmd]

I have noticed a calibration change of about 3(whatever units) from 70 degrees(my office) to 95 degrees(outside) .
With the generation 3 unit, it was about 10 or more
I usually calibrate at the end of a ride and just leave it alone thereafter so it is accurate the next time
Of course the first few minutes will be a bit off until the temp stabilizes
The lack of the auto calibration also helps since I was always cancelling it anyway

[Velocomp]

A change of 3 over a 25F range is extremely good.

[racerfern]

It's going to be hard to break old habits but I have to agree that intermittent wind offset calibrations are not needed. I'm pretty sensitive to when I see drops in wattage due to the wind offset having changed and when that happened with the Gen3 I would be looking forward to a stop so I could do a wind offset.

With the Newton I no longer have any concerns about wattage with changing conditions. At first I panicked seeing -3 to +3 wind offset numbers but I have to admit doing another wind offset didn't help the numbers at all. Tomorrow I'm going to ride away without doing a wind offset and I won't do one for the entire ride. I'm feeling the withdrawal pangs already.

[isaac]

I have the same experience with my Newton.
It seems to do a much better job with changing temp.
No wind cal for me unless there is extreme changes.

//Jonas

[rruff]

A change of 3 over a 25F range is extremely good.

Really? 3 N/m^2 off is a pretty big error, and 25F is a very common range on a ride.

BTW my Gen3 experiences very little offset change going from 70-110F. It's good in the summer. In the winter I see changes >3 and it appears to be unstable... ie I do the wind cal at a low temperature and it seems to wander anyway.

[markrhill]

While I like the Newton in general, I've had a couple of rides where the wind cam was totally off: during the ride the watts looked too good to be true, and when I downloaded I saw a false ~5mph headwind when conditions were actually calm.

Weird part is the problem is intermittent: most of the time the wind is fine, but now and then it's totally off.

I hit "wind cal" before all rides. Any ideas?

[Velocomp]

While I like the Newton in general, I've had a couple of rides where the wind cam was totally off: during the ride the watts looked too good to be true, and when I downloaded I saw a false ~5mph headwind when conditions were actually calm.

Weird part is the problem is intermittent: most of the time the wind is fine, but now and then it's totally off.

I hit "wind cal" before all rides. Any ideas?

The fact that you're doing a Cal Wind prior to each ride means that you're creating the possibility of calibration errors and differences before every ride.

Please post sample ride files.