This is very much an anecdote but I was surprised how long a spot of solar heated tyre takes to die down. I really would have thought that with such little mass, a bike tyre would cool back down in seconds, but it can still be there a minute or so later.

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Developing aero, fit and other fun stuff at Red is Faster

It changes fast enough to make accurate measurements difficult! Ideally you'd want to be measuring it at your test speed, but with my handheld IR thermometer that is tough to do.

Yeah good point. Right now I'm still figuring things out. I'm using ambient for the correction, but I'm also recording pavement temp and tire temp (using an infrared thermometer right after the test) for comparison. Where I live there hasn't much difference between the three most days over the fall/winter/spring. In the summer there might be, but I haven't done any temp correction in the summer yet so not sure. My expectation is that the tires will stay pretty close to pavement temp with maybe a little adjustment toward ambient but we'll see. Indoors when I roller test I find that the tires are a hair warmer than ambient but I still use ambient for the correction right now (until I have enough data to figure out what's best).

I use ambient...but, you need to use the ambient at the bike, not some local weather station :-)

In playing around with my IR thermometer on sunny and cloudy days, I found the tire temp basically tracked ambient temps (with an offset, of course). Sure pavement heats up, but it heats up the air above it as well...and the dominant heat transfer effect on tires is the convective effects over nearly the entire tire, and not the conduction at just the contact patch.

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http://bikeblather.blogspot.com/

Someday we should convene a little get together with a few people to produce a "best practices" protocol. I'll bring the beer.

Maybe we can convince Mark Cote and Chris Yu to finally host "aero nerd camp", like they had talked about :-)

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http://bikeblather.blogspot.com/

"Best practices" is just a euphemism for SOP to good experimentalists.

Either that or I have to be down in SLO to pick up the kid at the end of the quarter.

Convection may dominate, but in my testing the conduction from the road is an important factor. Rough guess would be 30-40% between air temp and road temp. Typically on sunny afternoons on an unshaded road I'll measure tire temperatures 20F+ warmer than the air.

Radiation?

I'm just thinking back to old days of outdoor summer track carnivals, with the high pressure singles on racked bikes going off like gunshots. Air temp hadn't changed much but the sun shining on black rubber I guess has some effect.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Big effect in still air, but less on a moving and spinning wheel. A ballpark free convection coefficient for air would be ~5-10 W/m^2-K. Solar intensity can be ~ 1000 W/m^2, though this will be acting on a smaller area than the surface of the tire and rim, there's still a lot of potential for heating it up. Once the air is moving the convective heat transfer coefficient is fairly flat with velocity, so I guess solar heating could still be significant.

Probably answered in a later post, but this version provides LIVE cdA. From the video I watched on this (GCN show), the prior versions only would calculate cdA after the fact in their included software suite.

This would change it to be a live field instead. Meaning you could do live on the road testing with the combination of this unit and a normal power meter.

The original iPod iAero provided a live CdA estimate. It was essentially useless, however, because it only displayed to two decimal places, and still jumped around all over the place. You could pick up on really big differences (e.g., sitting up with hands on tops vs. hunkered down in the drops on a road bike), but that was it.

And what about the PowerPod? It was marketed as a power meter but this new device appears to replace the PowerPod but requires a power meter.

EDITED:


So the USB connector on the Aeropod does work with a standard Micro-USB cable, it's just that the connector is rectangular, so you have to make sure not to insert the cable the wrong way - the more typical "trapezoid" shape solves this, as the cable will only go in the correct way.

Standard "trapezoid" shape Micro-USB cable that comes in the box:




Garmin 130, which uses the standard "trapezoid" connection:




Aeropod connection:

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Amateur recreational hobbyist cyclist
https://www.strava.com/athletes/337152
https://vimeo.com/user11846099

USB-C maybe?

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Washed up footy player turned Triathlete.

Looks like micro USB A: https://www.cablestogo.com/...ides/usb#micro-usb-a

Wow, bummer.

Yes, that might be it! I didn't have time to diagnose before heading into the office.

It's not a big deal needing to get different USB cables, but the fact that they seem to have used a very non-standard USB interface seems a bit perplexing to me. It's also nice to use a more "standard" interface because while I have piles of Micro-USB cables, a bunch of Mini-USB cables and a decent amount of USB-C cables, I can't say I already any USB-A cables.

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Amateur recreational hobbyist cyclist
https://www.strava.com/athletes/337152
https://vimeo.com/user11846099

You should be able to just plug your MicroUSB cables in, there's no significant differences in the pinout and that receptical will accept both A and B cables.

I'll give it a shot. It was admittedly early this morning, the cable didn't seem to want to fit, then I saw that the connection wasn't shaped like my Garmin, snapped a few photos and then a 2 year-old woke up in his crib and it was back to reality.

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Amateur recreational hobbyist cyclist
https://www.strava.com/athletes/337152
https://vimeo.com/user11846099