When interviewing a new client, the first order of business and, most important item is to discuss their goals. What do they want to achieve, what do they want to accomplish and when? Next, we discuss GPS head unit roundupall of the associated costs, both money and time … hard costs for coaching, power meters, head units, better equipment, bike fits, etc., as well as virtual costs associated with being out on the road training while others are sitting around the kitchen table eating dinner. We next discuss budget and then come up with a game plan.


One of the mandatory hard costs is a power meter, the other is a good head unit. As a USAC Level 2 coach, I require all of my clients to have these two items.


When discussing power meters, we discuss what’s currently on the market, what’s new, what are the best power meter(s) for their requirements, pros and cons, pluses and minuses, advantages and disadvantages and most importantly, how to use them when training.Power Meter


Next, we discuss head units. Some clients already have one, some want only the basic info needed for training and racing, others want ones with additional full mapping capabilities.


For a good review of cycling power meters, see The blog started in 2013 but continues to be updated.


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At this point, the client may have already or will be shortly shelling out for a high-end racing bicycle, a good set of racing wheels, an advanced bike fit, starting to pay for monthly coaching, and now they are told that they have to buy a Power Meter as well as a good head unit! I can tell that they say to themselves,


$2,500+ for a power meter and another $500+ for a head unit? That’s another $3,000!


“For the purposes of this article, a head unit is a computing device that
receives data and displays this information back to the cyclist through a mini display.
A Head unit may or may not record the information it displays.”


I quickly calm them down and say there are bargains in each of these categories. For example, Stages Cycling now has the Ultegra 6800 Power Meter for $580 and the 105 5800 for $530 , and Newton just dropped the price of their Newton 6 from $499 to $349!  Now that’s music to the ears!




Again, I reassure them that there are many price competitive options. 2015 has ushered in many new lower cost GPS head-units, which brings me to the purpose of this article.


“The purpose of this review article is to find appropriate
GPS head units that can be used specifically as a coaching & training tool,
therefore, cadence, heart rate and power functionality will be looked at in depth.”


Many new devices have become available this year. Among those are Cateye (2 models), Bryton, and Lezyne. Sigma has offered their current ROX10 which continues to be kept current via firmware updates. Sigma is

GPS Head Units
Click on Picture for Full Size Chart

currently working on a new model which should be out in 2016. Stay subscribed to since we have been promised an early version to play with.


Over the past 12 months, I have talked with hundreds of Southern California cyclists and the consensus is that most head units on the market today are overkill. Most of the comments were “way too many functions [that I am paying for] that I will never use”, “these head units are getting way too complicated to program/figure out, let alone use”, “all of this added functionality is making these head units’ way too large”, “the more functionality added, the quicker the battery drains”.


Just for the record, about ¾ of those interviewed already have an older Garmin 500 or 510 and half of these have asked me about other options.


Virtually every cyclist I spoke to has already
or wants to go back to a smaller/simpler/cheaper solution.


I am still seeing a lot of Garmin Edge 510’s on bikes while not too many 520’s. I think this is the case for several reasons, (a) the 510 still works perfectly for almost every cyclist, (b) the bike shops still have quite a few 510’s in stock and want to off-load those before selling the 520’s. The 510/520-sized units seem to be very popular with new GPS head-unit purchases as well as a great solution for cyclists that are downsizing from bigger/more complicated units. I’m seeing basically no 810’s and 1000’s.


But, all things considered, is the Garmin 510 or 520 the best solution for a head unit that is going to be used primarily for racing/training?




After getting familiar with these head units, I believe that they can be logically categorized into 3 distinct types being  (1) NON-GPS, (2) GPS, (3) GPS with full color mapping.


1. Non-GPS aka Cycling Computers, Bicycle Computers, Wired Computers, Wireless Computers.
The biggest name has to be Cat Eye. These units have a considerably lower price point, but usually has very limited functionality which might include speed, distance, a timer and odometer. Some higher-end units have optional accessories that give the cyclist cadence and heart rate. This category will not be evaluated in this article since they do not meet the minimum requirement for Power Based Training.


2. GPS – usually includes power and may or may not include some rudimentary GPS navigation. This is the category of head units that are evaluated in this article.
All head units tested are very high quality. They were all fairly easy to setup especially when following the setup & user guides. Each guide detailed a step-by-step setup process that allowed the units to be setup in under 5 minutes, and this included pairing with a HRM and Power Meter.
When evaluating the units, I looked at them with the eyes of a coach and what I would expect my athlete to be able to view and follow during a given work out.
The table below shows the product families in the left column and the highlighted yellow text represents the units I actually tested within these product families.
GPS Products Tested


3. GPS full-featured with Full Color Mapping – Full featured GPS devices such as the Garmin 520, 810, 1000, Magellan Cyclo 505 (previously tested). Not tested in this review.


After discussing power meters and head units, the next question I always get asked is “What fields should I display on my new head unit?” Below, I have added some recommended data fields to display. Of course, as the athlete gets familiar with the new equipment and training, they might want to change or add to any of these below, but, this is a good start. Some head units even have multiple pages that can be programmed so all you need to do is click one of the buttons to scroll through different data displays. This is done in real-time during the ride.


 GPS Data Fields



Each of the units tested had a fairly similar setup procedure. Turn the device on, enter your personal information, the bikes information then, configure the data screen(s). Most of the units have either 3 or 4 buttons. One button turns the unit on, two were for scrolling up and down the last was for selection or backing out of a screen.


Battery Life

After using the Magellan Cyclo 505 for the past year, I am accustomed to removing the unit from the bike and plugging it in to upload the data and recharge the battery. With these smaller GPS head units, even after 3-1/2 hours on a training ride, they are all in the range of 96%-99% remaining battery life. Even the Newton!
To recharge, you plug them into any ‘cell-phone’ charger with the supplied USB cable or plug them directly into any USB port on your computer. Either way, within 10 minutes, they are all back to 100%.



Since this is the most complicated part of the setup process, I highly recommend that you first write down on a GPS Head Unitpiece of paper what you want displayed within each data cell on which screen(s). Take time to go through the owner’s manual and pick and choose what data fields you want displayed and in which order. That way, it is a lot easier to setup the head unit.


Sensors and Pairing

I had not a single issue with any of the head units in pairing to the Stages Power Meter or my ANT+ HR strap. Each immediately found these sensors and, even after 4 months, have never lost or dropped a signal.
  • GPS – Each of these head units acquires the satellites very quickly. As soon as I turned on any of the units, they acquired their full complement of satellites immediately.GPS Head Unit
  • HRM – Each unit paired immediately to my original ANT+ HRM strap. I then tested different straps and each unit found, asked if I wanted to pair to the newly detected HRM, then quickly paired after I answered yes. During the 4 months of testing, no unit has dropped any signal.
  • Power Meter – After the first two revolutions of the cranks, all head units easily acquired the power meter. Again, after 4 months of testing these head units have never dropped a signal. I did have to replace the battery once in the Stages Power Meter.
  • Speed & Cadence – These sensors are usually not included in the original packaging, and, are usually an GPS Head Unitextra charge. Supposedly a little more accurate. You can upgrade to these if you wish, but, in my experience, the GPS within each unit does just fine. I actually did test a set of these sensors and, if you do want to use them, each unit has a user setting option that toggles GPS and these sensors. Each unit quickly acquired the sensors signals after flipping the switch from GPS to the Speed & Cadence sensors.


What (usually) Comes in the Box?

Each manufacturer ships a head unit as well as a handlebar / stem hockey puck mount. You also get a quick start manual, but, due to the size of some of these user manuals, some manufacturers require you to view their manuals on-line. Since they are in PDF format, you can also download then and save them to your PC.


If you want their ‘out front’ mount, these are available as an accessory and as an extra charge. Same applies for the HR strap and Speed/Cadence sensors. Do your research and know what you are getting with each model beforehand.
Most manufacturers have data analysis software for you to view and analyze the ride. Some are downloads from their websites’; others have included their DVD.
• Cateye –
• Bryton – website offline
• Lezyne –
• Sigma Sport –
• Magellan –
• Newton –


Not My Preferences

• Basically, every head unit in this test had MPH (or KPH) listed as the top data field. The problem I encountered with every head unit is that this is a hard-coded / non-user configurable field so you are stuck with it. What I would like to see is that these manufacturers can use ‘speed’ as a default, but, make this a data field that the user can change. The reason is if you set this up as a training device, you really don’t care about MPH. You care more about PWR, CAD, HR, %FTP, etc. This is one item that should be able to be fixed right away via a firmware update.

• Daylight Savings Time (DST) – Every head unit had a DST setting, but, in my opinion, their implementation logic is incorrect. They should follow the logic that is industry standard in PC’s and MAC’s, that being, if you live in an area that supports DST, then you click the checkbox in the PC’s settings and the PC will automatically toggle DST twice a year. Set it and forget it, you don’t have to touch it again. The implementation logic in the head units works like this. When it becomes DST, you go into the unit and click the DST box and the head unit will adjust the time by 1 hour. In 6 months, you need to go back into the settings and uncheck the DST box so the head unit will again show the correct time. Since these head units are full GPS, they have access to the satellites as well as the time function which they are already displaying from the satellites. If the DST box is checked, why can’t they flip the time automatically?


Easy Interface to PC

My desktop computer is an Intel i7 running Windows 10. Every one of the head units has nailed the PC interface to the point of automatically opening their data window (in Windows Explorer) as soon as the head unit is plugged into the PC. This makes for efficient transferring of files from the head unit to the PC or to any app such as Strava, Training Peaks, Golden Cheetah, etc. You can also use Windows to quickly delete old ‘.fit’ files on the devices after copying.



• Garmin Edge 520 – Promised but never sent
• O-synce navi2coach – Promised but never sent

Next time – Part II