Speed Sensor vs GPS

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Carcinogent
Posts: 4
Joined: Thu Jul 19, 2018 7:34 am

Speed Sensor vs GPS

Post by Carcinogent »

Hi,

In the recent years I have fallen of the 'tech' wagon, though the AeroPod seems to be the ticket for improvng my TT position and testing various equipment choices.

I use GPS exclusively for getting my speed, so I am wondering if i *must* use a dedicated speed seonor in order to use the aeropod for CdA reading (I have a Quarq Red PM).

Imo speed sensors are still some of the clunkiest and less than functional parts (zip ties really?) of what you put on a bike frame and GPS is much more accurate and reproducible as trying to replicate wheel sizes.

Therefore my question is: can GPS speed data be used with the Aeropod in order to get CdA data? GPS does not work at all or?

Thanks in advance for any input/insight on that!
Velocomp
Velocomp CEO
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Joined: Fri Jan 11, 2008 8:43 am

Re: Speed Sensor vs GPS

Post by Velocomp »

Yes, you must use an ANT+ speed sensor. The reason is that GPS speed is not accurate enough for the power calculations required by AeroPod.

The good news is that speed sensors have become much less clunky. Garmin makes excellent magnet-less speed sensors, which attach to the front wheel hub. No magnets and nothing bulky sticking on the bike frame.
John Hamann
russelldb
Posts: 32
Joined: Thu Jul 05, 2018 5:34 pm

Re: Speed Sensor vs GPS

Post by russelldb »

Will the PowerTap DFPM speed data be used, or must I get a separate ANT+ speed sensor?
Velocomp
Velocomp CEO
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Joined: Fri Jan 11, 2008 8:43 am

Re: Speed Sensor vs GPS

Post by Velocomp »

PowerTap power and cadence data are used, but you will need a separate ANT+ speed sensor.
John Hamann
russelldb
Posts: 32
Joined: Thu Jul 05, 2018 5:34 pm

Re: Speed Sensor vs GPS

Post by russelldb »

Interesting. I'll be honest, I'm a little annoyed about that. The powertap has perfectly usable speed data. The problem for me here is that I'll be testing my race bike, and therefore my race wheel, and I don't want to glue a magnet to a beautiful thing like my HED Jet+ Black disc. That would be wrong.
Velocomp
Velocomp CEO
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Joined: Fri Jan 11, 2008 8:43 am

Re: Speed Sensor vs GPS

Post by Velocomp »

You don't have to use any magnets or glue...a magnet-less Garmin speed sensor, wrapped around your front wheel hub, will do the trick!
John Hamann
Zoltan
Posts: 213
Joined: Mon Jan 23, 2012 9:47 am
Location: HUNGARY

Re: Speed Sensor vs GPS

Post by Zoltan »

It must be a misunderstanding. Also I think that Powertap hub is a special DFPM , since it broadcasts not just cadence and power data, but speed, too.

Frankly speaking since it is a rear wheel hub, its speed data is as perfect as that of any other stabdalone speed sensor. After setting tore circumference properly, of course.

On the other hand since it is positioned in a hub, and not on a crank, therefore its cadence data are not so reliable. I mean in low force cases it cannot identify cadence properly.
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Speed Sensor vs GPS

Post by Velocomp »

For AeroPod owners, we will be supporting the speed-sensor feature of the PowerTap hub.
John Hamann
Edgar Petrone
Posts: 2
Joined: Tue Oct 09, 2018 5:24 am

Re: Speed Sensor vs GPS

Post by Edgar Petrone »

This is great news. I have a Powertap G3 hub. I tried paring with it today but was not able to. I've only had the aeropod 1 day so much to learn about it. It looks great. Guessing there may be an update to support the hub later but may get a Garmin hub mount speed sensor in the meantime.
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Speed Sensor vs GPS

Post by Velocomp »

I also have a PowerTap G3 hub. Mine pairs without difficulty.

When you do the AeroPod pairing sequence with your PT, at the end of the sequence the AP light should show solid green. If it does, then you've paired to your PT speed sensor, too.
John Hamann
Edgar Petrone
Posts: 2
Joined: Tue Oct 09, 2018 5:24 am

Re: Speed Sensor vs GPS

Post by Edgar Petrone »

I tested again with my G3 hub and it seems it is pairing ok. I'm colour blind but I think it is going to solid green at the end of pairing in step 5c of the basic setup guide and not yellow as indicated there. But it is hard for me to see the difference between yellow and green. Going away soon so can't test it further but looking forward to road testing when I get back in 2 weeks!
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Speed Sensor vs GPS

Post by Velocomp »

Solid green is perfect.

You can check out "Tips and Troubleshooting" document to get a full understanding of AeroPod indicator lights.
John Hamann
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