This time 3 Polars and a Suunto SPARTAN ULTRA braved my ‘standardised’ GPS test route. It was a chance for the V800 to redeem itself from a poor first showing because of needing to be worn on the underside of the arm.
Also, of course, the SPARTAN ULTRA needs a first proper outing to test it’s GPS accuracy. This is with the latest firmware which supposedly includes GPS improvements. Previously, over the same course, the SPARTAN SPORT scored VERY well.
The route is shown in the image to the right and described in more detail along with the test methodology <here>. Predominantly it’s for running tests.
The raw FIT/TCX files are available <here< in a public folder along with an analysis spreadsheet of the results (there are three tabs in the spreadsheet).
In a nutshell:
- Almost anything seems to perform well on the easy sections
- The V800 redeemed itself and notably improved it’s performance when worn properly. It now has essentially the same good score as the TomTom Runner 3 & Spartan SPORT
- The Polar M600 did not fair too well, doing especially badly on medium- and hard-difficulty sections. Which was a shame as the oHR had been doing very well, a decent GPS score would have made it a compelling little unit.
- The Spartan ULTRA (new firmware) was significantly worse than the Spartan SPORT (old firmware, previous test) although doing a pretty good job on the easier sections. On a few sections the ULTRA seemed to perform well and then throw a wobbly.
- Is the SPORT’s GPS inherently better than the ULTRA? unlikely, possible
- Could there be good and bad units? no idea, I can’t think why
- Has the new firmware made things worse? doubt it.
- This seems to support my earlier tests over easy ground where both do well.
- This seems to support other more challenging tests on the net from other people that I have been mostly unable to replicate. Now I have !
- I’ve re-visited my initial view of the TomTom Runner 3 and downgraded it slightly. It now comes second behind the Spartan SPORT.
So we are now in the bizarre situation where the Spartan SPORT is the leader and the Spartan ULTRA is in last place. Very strange. The V800 and MIO Cyclo 505 both scored higher still in a bike test on the same route.
NB: These results are subjective and scored by eye over each section. What seems good one day may seem bad the next day when compared to a previous test. For this reason the scores are subject to continual change. The files are all public (above) if you want to delve further.
Next up soon: Another run with the Epson SF-820 and Garmin Forerunner 920XT, perhaps also strapping a Lezyne or MIO 505 unit to my arm.
Last Updated on 16 January 2026 by the5krunner
My favourite kit and nutrition
- Injinji – Runners protect your toes. Avoid discomfort and minor injury. Run more. Run faster. I use them.
- Garmin 90-degree charging adapter — The small adapter that keeps your charging cables tidy. Essential for race day. I use one.
- Garmin charging puck — the fastest and most reliable way to top up your Garmin before a session. I use one.
- Ravemen FR300 — Front light that mounts directly under your Garmin or Wahoo head unit. Keeps your bars clean and your beam pointed where it matters. I use one.
- Body Glide – The blue anti-chafe stick that all swimmers and many runners use. I use it.
- Maurten — The race nutrition trusted by elite athletes. Gels and drink mixes engineered to be easy on the stomach. I use them.
- Garmin Varia RTL515 — A radar rear light that alerts you to vehicles approaching from behind. Pairs with your Edge or Garmin watch. I use this model.
- Favero Assioma Pro RS2 — The power-meter pedals most serious cyclists choose. Accurate, easy to move between bikes. I use this model.
- Garmin Forerunner 970 — A serious choice for a pro-grade triathlon watch. I use this.
- Polar H10 — My daily driver for accurate, waking HRV readings.
- Wahoo ELEMNT Roam 3 — The bike computer that has the feature Garmin lacks: usability. I use mine on most rides.
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID
Don’t suppose you raised this with Suunto support?
I imagine others have raised similar issues.
Yes GPS has been raised but I doubt many comparative Sport v Ultra tracks