A little disclaimer: English is not my native language. You may encounter some mistakes and/or strange language constructs while reading this text.
Description of the event
The race was a 102 km ultra trail race with a total ascent of 4200 m, cut-off time set at 16 h (I had an ambitious plan to finish it in less than 13 h), and ambient temperature to be expected at 15-20C.
Formerly I participated in other ultra races, none that long, however. This was my first race with the FR735XT. Formerly I used the FR310XT which performed amazingly well (superb battery life, superb screen visibility in any lighting conditions, some advanced trail features). I even considered using it for the race instead of my new FR735XT, but eventually decided against it, because the FR310XT lacks 24/7 activity tracking and I would hate to loose that step count :)
Prior to the race I've been using my FR735XT since last december for running workouts (street running mostly) and triathlon training and racing. The ultra race would be the first activity of this kind and duration that I'd do with the FR735XT.
Use case
A short explanation how I planned to use the watch during the race.
- Registering the event for post-race analysis.
- Position and time awareness (how far in the race I am, how far away from next check point).
- Navigation assistance (easy to get lost on sparsely marked trail route).
Device configuration
My main concern would be battery life. The manufacturer specifies 14h, but I was aware that realistically I could not count on that. I was prepared to charge the device during the race (had a USB powerbank with me), but wanted to avoid it, if possible, and decided to configure the device in a way which would allow me to reach at least 15-16 h on a single charge, with time to spare.
So the first thing to go was optical HR. I don't need it during a race, and while it would be fun to look at the HR graph after the race, I judged that it's not worth the juice. For a short moment I considered using an external ANT+ HR strap, which would be more energy efficient, but I was affraid that even the most comfortable strap would become irritating after so many hours.
I never considered using UltraTrac. First, it's not accurate enough for me, and second, it was broken in the FR735XT (supposedly fixed with the last firmware update, but I had no chance to test it properly before the race).
An important feature for me was LiveTrack, as I wanted to keep my family aware of my position, so being aware that it was an additional strain for the battery, I decided to enable it.
The race officials provided a GPX course for the race and I had it uploaded to my watch.
So the summary of the device configuration:
- GPS with GLONASS off, UltraTrack disabled, smart recording.
- Optical HR off.
- ANT+ footpod paired and connected (some other ANT+ sensors paired but not connected).
- LiveTrack enabled (so BLE on and connected to smartphone).
- Backlight off.
- No custom Connect IQ data fields.
I disconnected the watch from charging about 20 minutes prior to race start. 10 minutes before start I entered activity mode, thus enabling GPS, and loaded the race course.
Now, before anything else, I have to report that I ended the race with a DNF. At 63 km and 9h10 I had to withdraw due to injury (pity, because my pace up to that point would put me in the top 15). However the time and distance covered allow me to extrapolate a little and assess the watch for long ultra running activities.
During the race the watch performed without any issues. When I stopped the timer after 9h10 I still showed about 50% of battery left, which allows me to expect the battery to last for at least the 16h cut off time, possibly a little longer.
Very subjective verdict
So....
If you're wondering if I find the FR735XT useful and practical for ultra-long trail runs, the short answer is yes. All the essential features worked as expected, the GPS accuracy (distance, pace, position) was at least satisfactory and the navigation feature helped me stay on course where I saw other competitors struggling to find the right way. One thing to note is that a significant part of the route was in a dense and tall forest which could affect GPS accuracy, but I saw no issues there.
LiveTrack worked flawlessly, according to my wife, who monitored my position regularly and at all time was aware where I was and how I was doing, sometimes better than me myself :)
The device itself is very light and comfortable, giving it a slight edge over the heavy and bulky F5 or F3 (or my old FR310XT, for that matter).
Important thing is that the watch can be relatively comfortably charged on the go. I did not have the need to do it during this race, but I tried it out several times before during other workouts and it worked without issues. One thing worth remembering, though: When charging the device, you loose optical HR, even if you still wear the watch on your wrist. This would be no issue during the race, because, as I mentioned before, I disabled OHR anyway, but it is something to be aware of.
There are however some issues worth noting (in order of importance).
- The most important feature that I miss from my old FR310XT is the course elevation plot. This is super-useful for trail running because it tells you what kind of terrain to expect, how long the climb/descent is going to last and so on. Without it I had to rely on the elevation profile printed on my race bib, and that is neither very accurate, nor comfortable to use.
- Getting the GPX course into the watch was a PITA.
- Loading the course upon starting navigation takes a really long time (about 5 minutes). The ancient FR310XT is much faster in this regard.
- Once navigating a course, 2 additional data screens are added to the data screen carrousel (ETA and virtual racer), and there is no way to disable them. This makes scrolling through data screens more time-consuming in case you don't need those additional data screens (and I don't need them).
Ok, that's all. Thank you for reading this far. I don't know if I included all important information, so feel free to ask any questions. I'll try to answer them as best as I can.
