First up, I am a big fan of the Golden Cheetah software (http://goldencheetah.org/) and I have used it for years. More recently I have been looking to utilise the Realtime Training functionality as a means to do bike fits and testing while out of the studio.
To make this work you need a trainer or sensors that transmit speed (and preferably cadence) data, via ANT+, to your computer or laptop. An additional benefit is that for some trainers you can also see a 'virtual power' figure, which is calculated of a power curve for that type of trainer. I have the Lemond Revolution as my race-day and out-n-about trainer and this is one of the trainers that provides virtual power so I set about testing the functionality.
These are my thoughts on the setup process, accuracy and usability of the system as it stands at the moment.
Before delving into the details, some caveats on this review.
- I was using version 3 (release candidate 2) to complete the tests on both my PC and Laptop. Version 3 provides native Ant+ support whereas my normal version (2.1) relies on quarqd (which is reputed to be troublesome to get working correctly).
- Both of my systems run Windows 7 in 32bit
- I was using the Lemond speed and cadence sensors with a Garmin USB2 ANT+ Stick/Dongle
- I do not have any Garmin software loaded on my systems that utilise this dongle
Ok, so the first thing to set up when you want to use the RealTime training feature is your device. In v3 this appears to be pretty straight forward but let me tell you now, this is probably the most frustrating part of the entire process.
Once you enter the training mode for the first time you will be asked to add a device, from here select Native Ant+ and you will see a screen/window with a range of sensors listed, along with device Id's, device values and a paired or searching status. On my first few attemps I could not for the life of me get the system to detect anything other than my HR strap. After trying a number of things I discovered that you needed to ensure the device/sensor was awake BEFORE you tried to add the device. The problem with this is that it can be damn tricky trying to ride the bike, then jump off and start adding a device before you miss your opportunity. This proved much easier on the laptop as I could set it up right in front of me to minimise the lag time. Getting up to a good speed also helps as it keeps the rear wheel moving.
The other thing to be aware of is that despite the new device window containing a "pair devices" button - it doesnt work. Infact the official documentation tells you to ignore it otherwise you will have problems. Best to leave it alone.
The last step in setting up the device is to give it a name, select a virtual power option and then to select the default metrics to display. For me this was all four: power, speed, cadence and heart rate.
Once this is all done, your device is set up and you do not need to go through these steps again. It's worth noting that while the documentation suggests you do not need to have the device setup recognise the individual sensors (it says it will pick them up when you start training) I found this to be less than successful.
So, with your device all set up it's time to start training. This is also reasonably straight forward, albeit not without it's problems. The problem is that you first need to click the 'play' button/icon to start the session. This starts the timer and sensing for the ride data. Unfortunately its not an easy thing to do this on the bike so you need to do it before you get on and then have a brief period of zero data before you start riding. The time lag between starting the session and starting riding also appears important as if you wait too long the sensors won't always pick up. Additionally I have noticed there are times that the sensors dont pick up at all and as with the device set up it appears to work best when you dont start your session until after you have started riding, which means you then need to get off the bike, start the session, then jump back on. Very annoying!
Once you get everything working properly then it's usually smooth sailing, although more than once I have had the training data freeze on screen. The only solution is to then exit the training mode and start all over again. Again, very annoying!
If everything is working as it's supposed to then you should see all of your training data and a chart with some lines which track each metric. Pretty straight forward - except if your initial color setup isn't right you may not see some of your data. In both of my v3 installations the plot background color was set to black - which just so happened to be the same color as the power data. This meant I couldnt see it and I actually thought it wasnt working. However once I figured it out I simply changed the plot background to white and there was my power data.
Speaking of the power data - the virtual power feature is a nice addition but it has one fatal flaw, there is no calibration process. Now truth be told I was aware before hand that the Lemond Power Pilot (Lemond's custom computer for the Revolution) uses it's own proprietary coast down procedure to ensure that the power data is correct and that it was unlikely this would be incorporated into Golden Cheetah. However, what I was hoping for was for someway to manually adjust the power readings based on my Quarq data. My Tacx trainer and software has a function where you can scale the power up/down by a certain percentage and a feature like this would be handy. However the approach is unlikely to be the ideal solution. The reason is that the % increase applies across the entire range of power values. For example a 4% increase would mean the virtual power readings go from 100w to 104w and 300w would become 312w. However, my own testing has shown that for the Lemond, the issue is more related to the 'intercept' with the virtual power readings showing approximately 30 watts on the low side.
You can see this more clearly in the image below, which is a chart I generated based off the power data Golden Cheetah (for the Lemond) and my Quarq data (from my Garmin, downloaded into Golden Cheetah).
As you can see in the chart the Quarq data is consitantly higher than the virtual power of the Lemond from Golden Cheetah. The average error is basically 30 watts, however it is worth noting that while I syncronised the data at the start of the rides, the timing of the saved data does drift out across the session. This testing session was quite short (around 11mins) and during that time the values drift from syncronised to 9 seconds out. However, considering the structure of this session (constant efforts at different power outputs) this should have minimal impact on the error rate.
So, what do we need to get the virtual power data correct. Personally I think two options are necessary:
- The ability to provide a set +/- power value to the virtual power. For example I could add 30 watts to my Lemond and the power data would be accurate enough to be usable.
- The ability to adjust the power curve, like the percentage method used by Tacx, to account for larger drifts in power as it increases.
The final word
It's always hard to recommend for or against a product that, like v3 of Golden Cheetah, is still in development. However, I sincerely hope that the designers are able smooth out the issues and and add the extra functionality before it hits mainstream release.
It's also important to note that the setup and virtual power issues that I identified may not occur for other systems or trainers. If you already have the tools necessary to try out the system then I encourage you to give it a go and see for yourself.
For me, I will be having a closer look at how I can get the power values to match up more closely before I put this setup into action.
- The current version of Golden Cheetah can be downloaded (for free) from http://goldencheetah.org/
- Version 3 (release candidate 2) can be downloaded from http://goldencheetah.stand2surf.net/
- The instructions on setting up ANT+ devices for the RealTime training mode can be found at https://github.com/GoldenCheetah/GoldenCheetah/wiki/Realtime-set-up