AeroPod, PowerPod and Newton

I am receiving a message on the ibike that the calibration ride is bad. I've made two attempts. I don't mind the riding, I just want to get the ipro working. FWIW, I upgraded from a GI and used iBike3 to send some of the data from the G1 to the G3 (miles, alt). I don't believe that I sent any profile data but I could be wrong. I did the four coast down rides and then headed out for the calibration ride yesterday. I repeated the calibration ride today. Attached is a screenshot from iBike showing the rides and measured/calculated data. I also noticed that the Crr in the ibike setup is 655.

I am thinking that I should totally wipe out the config and repeat the whole process. What is the best way to wipe out all of the config/setup? Is this the right thing to do?

Thanks,

Todd

The riding tilt of -6.7% is the problem. It should be somewhere around -0.5%

Did you do a tilt calibration prior to the cal ride?

Is there anywhere that tells us the range of values to expect for crr, tilt, cda, aero, wind scaling, etc? That would be helpful to me to understand where my calibration is off.

I don't want to keep bothering Aaron with my questions and this thread is relevant to my problem (or the problem I had). It might help you.
I kept getting a bad tilt and was unable to send my profile to the Ibike.

It got worse, I started to get bad coast downs. Ended up with one good cd out of about 12 attempts. On 3 separate occasions.
I put the Ibike on a different bike and got a profile on the first attempt. Told Aaron.
Aaron suggested I do the tilt whilst on the bike. It worked.
What I want to know is why did it work. Anybody able to answer this?
My other question concerns the tweaking of the information gathered from the cd's and calib ride.
If the Ibike calculated the Crr at 0.0111 on the one bike and .0064 on the other, why would I change them and what difference does changing them make (up or down) I understand to a certain extent that it got to do with road surface but surely Ibike calculates the surface type from the cd's and calib ride? What it gives out should be correct, shouldn't it?

This was a bike with 650 wheels and aero bars (regular, not shortie clipons) and a very short stem. I thought it might have been tyre pressures but that was not it.

Anyway, I have two good profiles now, one for each bike so I am a happy camper. I would just like to understand a little more, in as non technical way as possible.
Thanks
Stephen

I did a wind offset and tilt prior to the coast downs and calibration ride.

I will do another tilt and see what happens. Is there any wisdom in wiping the whole config and starting over?

Also, as a feature request in the ibike app, would it be possible to extend the logic that reports calibration rides as 'bad' to highlight suspect data and recommend fixes?

Thanks,

Todd

Interesting config history. I recall seeing a video that suggested that good tilt results were obtained when standing over the bike and using your legs to steady the bike and firmly holding the handlebars.

This is what I've done for my tilts with G1 and for this G3 attempt.

Todd

ludlaw wrote:Is there anywhere that tells us the range of values to expect for crr, tilt, cda, aero, wind scaling, etc? That would be helpful to me to understand where my calibration is off.

There are soooooo many variables that giving expected ranges of values isn't easy.
With that said,
CRR .004 to .007
Tilt -.25 to -.75
CdA .250 to .450 (generally at 0.350 to.425)
Wind .700 to 2.700 (generally, stem 0.7-1.1, bars 1.1-2.1)

Bear in mind that numbers outside of these ranges are very plausible.

If you get a tilt of -1.5 or a CdA of .9 then something's wrong. In the case of tilt, maybe something's moving/shifting/loose in the stem; in the case of CdA your wind calculations are suspect.

Barring extremely unusual circumstances or setup, for a weekend warrior you could take the default iBike settings and just ride. After all, if your wattage numbers go up over time with a training regimen then you're improving. When push comes to shove isn't that what we care about?

I've had this happen twice in the last week. (I changed my ride position and built some new wheels . . .). I checked the tilt, did the wind offset, etc.

At first I was tempted to think that it had something to do with going straight from the coast-downs to the cal ride in the set up menu (i.e. not backing out to the main screen then going into cal ride. I think this happened with 3.02 to me once, and the unit processed my ride as like 400 coast downs). So, the first day I did two cal rides--and the second one, where I trip reset before going into cal ride, came out fine.

When I processed the c/ds and cal ride, though, both cal rides came up, and the numbers were very similar (ride tilt for one was 0.0, the other -0.1) and the wind scaling for both was around .69x to .70x. [This day was for the new ride position].

Then, after I finished building the wheels, I took 'em out to do coast-downs. Once there, I thought, what the heck, I'll do a cal ride too to see if it gives me a "bad cal" if I exit set up and go back in. And it did. RIding tilt was -0.4 and wind scale was .76xish.

All I can figure is that the unit didn't like the wind, which was around or over 10mph, and slightly x-wind for both of these days.

But still, despite the unit labelling the cal ride "bad," the results are in line with most of my previous cal rides on my road bike.

racerfern wrote:Bear in mind that numbers outside of these ranges are very plausible. <snip>There are soooooo many variables that giving expected ranges of values isn't easy.</snip>

After reading these posts and thinking about the coast down and cal ride procedure as well as the fact that you can use the estimate feature, it seems logical that either the iBike App could highlight issues that are at the far end of the bell curve. More importantly, it would be _really_ nice if the iPro wouldn't let you perform a CD or cal ride if either the wind offset or the tilt are out of spec unless the user choose to override the warning. Yeah, I know that there are limited resources in the HW to perform these functions and arguably, there are features that would be of more value on a regular basis.

Still, it would be nice to have the analysis SW give you a heads up when it finds cause to warn of a change in tilt or other variable.

Also, when performing a tilt calibration, does the ibike ever give a 'bad tilt' message? **Edit -- I did a new tilt at a forced bad angle and got a bad tilt message. Did another tilt and got a tilt ok message. **Edit
Does the ibike compare the results of new tilt calib to the old value and complain if there is a significant change in the values?

Todd

The iB3 gives higher weight to good coastdowns than to questionable ones. In addition you can manually select any one or a number of coastdowns and choose to use them or not.

It's tough to absolutely know if the wind offset or tilt are bad for a coastdown. However you will get a bad coastdown message if something clearly goes wrong.

You will get a bad tilt message if you have a bad tilt calibration.

racerfern wrote:
You will get a bad tilt message if you have a bad tilt calibration.

Except (in my experience anyway) when you do a good tilt, wind offset and calibration ride but for an as yet unexplained reason you are unable to send the profile to Ibike because of the "tilt out of range" message which I assume is happening during the ride? Actually its probably the cause of the bad coast downs as well.
This is not a criticism, just my observation, and solution (for me) as written earlier.
So if one uses the input screens to go with the default settings, can they be extracted from the Ibike to see how they compare to an actual profile?
Just a thought,

Stephen