This is my 1500m weekend swim course. I do it a LOT.
The SPARTAN is in RED and clearly the track is not as good as that of the 920XT. The SPARTAN seems to have me swimming backwards in places which is clearly wrong. I may be bad but I’m not THAT bad.
The 920XT’s algorithm seems to take notice of fewer GPS points (or the SSS takes note of more). Whichever way you see that happening I just know what the track should look like and the Garmin is quite a bit closer to today’s reality and their algorithm works better, IMO.
The Garmin had me doing c1600m and the SPARTAN SPORT had me doing c1800m. I probably swam 1550m.
I’ll keep this post short as there is not much more than can be meaningfully said.
Last Updated on 16 January 2026 by the5krunner
My favourite kit and nutrition
- Maurten — the race nutrition trusted by elite athletes. Gels and drink mix engineered to be easy on the stomach.
- Garmin 90-degree charging adapter — the small adapter that keeps your charging cable tidy at the stem. Essential for race day.
- Garmin charging puck — the fastest and most reliable way to top up your Garmin before a session.
- 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.
- Garmin Varia RTL515 — radar rear light that alerts you to vehicles approaching from behind. Pairs with your Edge or Garmin watch.
- Stryd — the footpod that brings running power to your Garmin. The single most useful running upgrade I have made.
- Favero Assioma Pro RS2 — the power meter pedals most serious cyclists end up choosing. Accurate, easy to move between bikes.
Reader-Powered Content
This content is not sponsored. It’s mostly me behind the labour of love, which is this site, and I appreciate everyone who supports it.
Support the site: Follow (free, fewer ads) · Subscribe (paid, ad-free) · Buy Me A Coffee ❤️
All articles are written by real people, fact-checked, and verified for originality. See the Editorial Policy. FTC: Affiliate Disclosure — some links pay commission. As an Amazon Associate, I earn from qualifying purchases.
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
why do not you compare well with polar v800?
I think that the real test would be more serious in a straight line as in open water
I only have so many hours and so many watches and so many arms and so much time. it’s a good point tho I should do more with the V800 in OWS in the future. In this case it would not have made the Spartan look any better…it was still going backwards.
Could you repeat this test with the new Garmin 935, please?
I plan to do that at some point in June.
This is NOT MY JOB. I have a real job too 😉 Whilst I do get some awesome and much appreciated support from readers the bread and water comes from elsewhere and not the5krunner.com 😉