Tuesday, December 31, 2013

Minoura LR340 Live Ride Mag Trainer - part 3 - riding a course

Part 1 of this review / quick start / how to dealt with setting up the Minoura Live Ride LR340 trainer and the bike. Part 2 was getting the iPhone to see the HRM, Cadence and Wheel sensors, and general setup of Live Training.

Part 3, this one, is how to ride a pre-defined course. The reason for calling all this out separately is that the instructions are firstly in Japanese only, and secondly wrong. For example, Minoura say there are some pre-loaded courses, well there aren't.

First off, getting a suitable ride file. Live Training can accept either KML or GPX. If you use Strava and you want to ride something you already rode, or someone else already rode, GPX is the way to go. You can use Google Earth to create a KML of course.

Assume for the minute you want to re-ride one of your own rides, and you uploaded it into Strava, so you've got access to the data. The easiest way I found was:

  1. Create a new Strava account - the reason is we want to crop the ride, but leave the original, else we'll lose the KMs, and that would never do, right?
  2. Then either:
    • Download the ride from your 'master' Strava account. This gives you a GPX file
    • Find the original Garmin .fit file
  3. Upload this file into your secondary Strava account
  4. Crop it to the bit you are interested in
  5. Export from secondary Strava. This gives you a GPX of that climb, or TT, or whatever.

Here's an example from a recent ride

Then we need to get this GPX onto the iPhone so Live Training can see it.

The only way I know of is to use iTunes to sync the GPX file.

Open iTunes:

  1. Select your iPhone on the left hand side
  2. Select "Apps" at the top
  3. Scroll down and select "Live Training" at the bottom on the left
  4. Drag the GPX file you created above into the window bottom right
  5. Sync changes

To make this into a Live Training course, go back to the iPhone, open Live Training, and:

  1. Touch "Course"
  2. Touch "New Course"
  3. Give it a name
  4. Touch "Load KML/GPX file"
  5. In the lower part of the screen you see "Documents Folder" and you should see the GPX you just uploaded. It helps if you gave the GPX a friendly name
  6. Save all that, and when you go back to the Course screen you should see the course and a little thumb nail.

To ride this course, make sure you are on the Course screen, touch the course you want, and it loads up. Get yourself ready, start pedalling, confirm the HRM, cadence and wheel sensors are online and responding, set the remote control to the value in the Live Training window, and when ready touch "Record".

And off you go!
If the video above doesn't play, try this http://youtu.be/gDOUAK-zPfs:
Part 4 is next: how to create courses for the Live Training App so you can ride them.

Sunday, December 29, 2013

Minoura LR340 Live Ride Mag Trainer - part 2 - getting the Live Training App and ANT+ sensors working

In part one of this review / getting started guide for the Minoura Live Ride 340 magnetic trainer, I showed how to physically get it to the point of being ready to ride.

With the bike itself ready, we turn to the big selling point: the Live Training software. You'll recall that the Minoura Live Ride trainers have neodymium magnets which basically means we know how much power is required to turn the unit. This means we can use the iPhone App(s) to have calibrated rides, or if your prefer, you can re-ride existing courses. Yes eventually I can tackle, virtually, Mont Ventoux.

You get the best from the Live Ride trainer, you'll need the following:

If you have these already, then great. If not, you have just approached a major fork in the cycling accessories road ie Bluetooth LE or ANT+ ? I'll address this conundrum separately. In the meantime, I'll assume you are going with ANT+, since most folks who ride for real and have a Garmin GPS unit eg Edge 500, 800 etc, will already have ANT+ since that what they use.

The Minoura instructions say that nearly all ANT+ sensors other than Garmin will work. Actually I found the Garmin HRM and GSC-10 worked fine. YMMV of course.

So you'll need:

So this will cost about $250 to do in ANT+.

When you plug the iPhone into the case, its all plug and play: nothing to install. 

Next suggest you install the Wahoo iPhone app. Its free and allows you to connect the sensors and confirm all is working OK.

Then start the Live Training App. Touch "Settings" and work your way through each field.

You can then go back to "General" and do a quick ride. If all is OK you should see your data:

Here's a screenshot (not mine... I don't get SoftBank LTE in Sydney :-) ). The "9" at the bottom in the middle is the resistance. For general rides you set it to be whats on the Live Ride trainers remote control. For riding a "Course" you set the remote to what it says on the iPhone's screen.

If all is good, move to Part 3 to see how to ride your first Live Ride Course.

Saturday, December 28, 2013

Minoura LR340 Live Ride Mag Trainer - part 1 - setup

Recently I got a Minoura LR340 Live Ride indoor mag trainer. Its has two features that sold it for me:

  • The Live Training iPhone App. More on that aspect in part 3.
  • Its has newly developed magnetic resistance magnets, which are sufficiently accurate that you can set it up to provide specific, calibrated resistance eg 300W.

The trainer arrived in a solid box, and after opening it of course I read the instructions. The words and explanation are clear enough, but that pictures less so.

So here are some actual photos to help anyone wondering how to get started.

  1. Get the tools you'll need: a spanner and 4mm hex key

  2. Spread the legs of the unit. Mine had the rubber feet on already, while the instructions say you have to fit them.
  3. You have to remove a bolt

  4. And then attach the unit. You don't need to make it massively tight. If you over tighten the unit won't pivot correctly when you put your bike on.

  5. Next put on the adjuster bolt. This is required to allow for different wheel and tyre sizes

  6. And here's what it looks like, from the side

Next part is attaching your bike and the remote controller.

Replace your quick release skewer with theirs, and then turn the handle on the right hand side so you can get the bike on. Tighten up the handle, and here we are

Then attach the remote control to the handlebars.

And thats it.

Well one more thing... you'll need to lift the front wheel up, so here's a 1 cent piece of wood doing the job.

Next, in part two we see how to get started with the Live Training App, the iPhone, Wahoo ANT+ adapter, HRM, cadence and speed sensor

Monday, December 23, 2013

Final thoughts on sprocket use - pedal cadence and overall accuracy

From my two previous posts (#1 and #2) on my actual use of the 11-28 cassette, I had decided to not include data points where the recorded cadence went below about 50. My reasoning was that actually its quite hard to pedal that slowly and would likely only occur as I was rolling to a stop and changing gear ie soft pedalling.

Is this a sensible limit? Well I tried various values, and 48 seems about the best. Here's teeth vs speed for a 4.25 hour 125km ride. After I removed all the data points with either zero speed or zero cadence, I still had over 13,500 data points:

You'll see the fairly sharp cut-off on the lower side of the data cloud - thats the 48 rpm cut-off at work. When I adjust that value, the data either gets messier (ie noisier) or the line gets too sharp ie I'm removing signal.

So, 48 it is.

Next question, how does the actual data compare to modelled data? I created a matrix of teeth vs cadence, where the intersection is speed (in kph):

And a chart:

Now, if I scale and overlay them (I've drawn in lines to represent what my cassette offers):


Another thing you might notice is that that the lines of cadence are quite distinct, which we see zooming in:

What we're seeing here is that the GSC-10 only records integer values for cadence.

The cloud we see is thus where two imprecisions from sampling frequency and data recording surface:

  • cadence to 1 rpm only
  • speed and cadence recording at 1Hz intervals

If, in the example here, the number of teeth boils down to 17 ± .25 then that works out to be about 98% accuracy.

Sunday, December 22, 2013

Adobe Acrobat: four things I hate about you

Recently I got an email from Adobe entitled "Top 5 reasons to get Acrobat XI". OK, I'll bite...

Here's two three four reasons to think very carefully if you do.

  1. Acrobat's security sucks. Big time. How can this be? They are a big company. Anyway, no need to believe me, have a look at US-Cert.
  2. Who thought to build javascript support into PDFs? And it on by default?

    OK, to disable it, go to Preferences, select Javascript on the left, then deselect "Enable Acrobat Javascript" and save.

  3. The patch policy sucks. They don't do combo / roll-up patches. So for each update I have to run a patch? The version on my installer disk is an early v9, and the first patch takes it to v9.10. And then.... the madness... Oh my F goodness... to get from installer disk version to current state takes 23 patches? Run individually of course, each one requires admin credentials. Thats an hour of your life gone for ever.

  4. Upgrade pricing... so if I want an up to date version, its AU$282?

Seems I'm not the only one here...

Tuesday, December 17, 2013

More thoughts on bike sprocket / cassette usage

Previously, I discussed how I used the data from my Garmin Edge 500 with GSC-10 pedal and cadence sensor to analyse which sprockets on my cassette I use, and which I don't.

The graphs I produced, such as this one

seem to show clustering of results around what the cassette offers (its a Shimano 105 11-28 so has 11-12-13-14-15-17-19-21-24-28).

The next question is: if these are my results from actual ride data, what would a theoretical approach look like?

So I took the data from a longer ride (roughly 65km over 2.25 hours giving about 10,000 data points), and again plotted speed vs cadence: NB speed in kph, cadence in Hz.

Again, I used Google Spreadsheets to calculate theoretical values. What I did was to create a matrix of speed vs teeth, and each data point is the cadence in Hz, populated using the formula discussed previously:

which I've plotted. Each coloured line represents a particular sprocket

So is the analytical model valid? Here's the two charts overlaid and scaled

Woot! I would say that means yes!

Next: is the pedal cadence I've arbitrarily set OK? I test this in a bit...

Saturday, December 7, 2013

What gear(s) do I mostly use on my bike?

Inspired by this site where the author explores which gears he most uses, I thought I'd look into myself for my rides. He uses gear inches, while I decided to use the sprockets on the cassette.

My bike has a Garmin Edge 500 GPS and the standard Garmin GSC-10 cadence sensor for pedal cadence and wheel speed. The maximum sample frequency is every second. This is not, of course, enough to get properly accurate data (sampling frequency theory etc) but it'll have to do.

The Garmin produces a .FIT file which is binary and cannot be read directly, so you need to use something to convert it. Garmin have their desktop Garmin Training Center software which exports to both .TCX and .GPX, or you could use their connect.garmin.com web application. Both TCX and GPX are xml-a-like so a regular text editor can read them.

If you do use the Garmin software or their web site to convert the .FIT file, then one problem is that the xml like structure is not very human friendly so you need to convert to something like CSV.

The next problem is that for some reason the TCX / GPX and thus the CSV does not have speed data in it. After looking around, I found Ascent which runs OK on my OSX 10.8.5 laptop. It imports the .FIT directly, and exports nicely directly to CSV, with speed.

Next problem: Ascent outputs speed (yippee!) but to only one decimal point of accuracy, in either mph or kph, and thats not enough. I was pretty sure the Garmin records metres / second in the .FIT file, which would be a much better bet.

After some more looking around, I found the Garmin online fit repair tool web site. You upload a .FIT and get the raw data as .CSV. Speed is in metres per second to 3 decimal places, and no intermediate step - great, now I'm making progress! (Note yes I know GPS is not accurate enough to really use 3dp, but when the Garmin uses the GSC-10 it takes speed from the wheel / spoke sensor, which is a lot more accurate - more later).

Next step is to upload the CSV file into Google Drive and convert to native format.

After uploading, you scroll up and down and you notice some lines with what looks like bogus data on them. I presume that the converter web site is not interpreting the file completely correctly. Cleaning it up manually was OK, but a 4 or 5 hour ride which would have potentially 20,000 data lines in it, would be very tedious. Here however I was using a 50 minute commute file, so only 3000 or so lines.

Since I have speed in m/s, and cadence in rpm I'm nearly there.

Lets start some maths! Some definitions:

F (chainwheel) - teeth
R (cassette) - teeth
C (cadence) - rpm and Hz
S (road speed) - m/s and kph
W (wheel) circumference - metres

F = 52 for me, and I almost never come off the big ring :-)
R is what we want to calculate
C we have
S we have
W = 2.104m for my 700c with 25mm tyres (NB the book number is 2.105 however the Edge 500 had calibrated to 2.104 which is OK for me)

The basic formula we need is:

F/R * C * W = S in m/s


F * C * W / S = Rear teeth

since F and W are fixed we can turn them into a constant

ie 52 * 2.104 = 109.408

so to calculate teeth

109.408 * cadence (Hz) / speed (m/s)

So all you need to do is add a column in Google spreadsheet to do the calculation for you.

The first time I did this, I got two problems:

  1. When approaching a junction I often soft pedal to change gear, this means that when I'm doing this, the ratios don't work. To fix this I decided that if the cadence was less than 40 rpm then I would zero it. The formula I used is:


    this both zeroes for less than 40 rpm and converts into per second ie Hz
  2. If the speed is zero then you get divide by zero errors, so when calculating teeth I also used a conditional:


    so this means either I get the number of teeth or I get zero, which is when either I'm not pedalling and / or stationary.

So what do I get? Well here's the first chart: sprocket vs frequency of use.

If this commute ride is representative of my rides generally, it shows that I just don't use the 12, and hardly use the 13. My current presumption is that the very low values for 16, 18, 20, 22, 23 which the cassette doesn't have (its a 105 11-28 with 11-12-13-14-15-17-19-21-24-28) suggest that this method has statistical validity.

Above 24 we're into noise. My guess is that on the big end of the cassette I'm going so slowly that sampling frequency of speed on the wheel becomes an issue. Remember we only get 1 sample recorded per second, and at say 1 m/s which is 3.6 kph the wheel is only going round at 1/2 Hz or so. If you were to take a minimum speed of 2.2 times the sample frequency that would equal about 4.5 m/s or about 15 kph or 9 mph or so.

Then I can do speed vs cassette teeth. You can see how the results are clustered around what my cassette offers.

And speed vs cadence

If I get chance I might try this with data from a longer ride.