Polar Street X Put Through 200 Miles of Cycling, HRM 600, Pirelli and more

Half-heartedly training for Mallorca 312? I fixed that with two back-to-back 100-milers (one hit 115 miles), fuelled by coffee and cake, perfect weather, and live tests on the Polar Street X, Garmin HRM-600, and Pirelli P-Zero Race SLR tyres.

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I’m currently half-heartedly training for Mallorca 312, a 200-mile one-day event with a 5,000 m elevation gain. Realising I’ve not been taking the riding seriously enough, I left this blog for a few days and did a couple of back-to-back 100-mile rides. Actually, one was more like 115 miles, and both involved the fuel of kings, i.e., coffee and cake in copious quantities. The goal of the ride was preparation time with mates, but I still wanted to throw in a couple of tests at the same time.

Preparation – Routing

I got the Strava route link, but it somehow loaded as multiple routes chunked into smaller segments. I didn’t want that, so I resolved to use Ride with GPS, which I find is generally a bit easier to use. I’ve been testing some interesting beta features on RwGPS that should become public soon, but I won’t mention those yet. Perhaps they would have helped enrich my route creation, but I did it the old-school way in the end just to save time.

My thoughts on routing were:

• We had a few times when the group split up, and it would have been useful to include the pre-planned coffee stops on the route, but we didn’t. That would have added yet more minutes to the route creation and planning that no one could be bothered to do. Marked coffee stops would have saved someone else from going down a big hill unnecessarily, only to come back up just to get coffee and breakfast with the rest of us.
• Making a rich and useful route just takes too long.
• Getting it to your Wahoo/Garmin never seems quite as easy as it should be. Admittedly, both platforms are almost there, and routes do often magically appear after a sync. But I’m an infrequent navigator, yet I still have many routes on Wahoo. One of the routes I synced wasn’t created recently, so I had to scroll through my on-device library to find it. A feature I think would be very useful is similar to time-sensitive notifications on my iPhone. I’d like a time-sensitive route that just vanishes after a week or so, never to clutter up my route library again.

Testing HRM-600

I was a bit short on wrists for proper testing. The usual two were insufficient for the job at hand. So I decided to record the HR data on my Garmin HRM-600 chest strap and leave my other Garmin devices at home. After all, that is what the HRM-600 is designed to do, right? I thought I would start the workout on my iPhone at home, then leave the phone there and see how long the strap would keep recording. Ideally, it would go through the following evening, when I would have a full 200-mile HR track. I use my Apple Watch Ultra 3 to pay for things, make 5G calls, and send/receive messages, which takes the place that most people use a phone for. Here are the problems:

• For some reason, I had unpaired my HRM-600 from the Wahoo while Wahoo was testing the TymeWear VitalPro ventilatory threshold strap. En route, the HRM-600 was invisible and would not pair. I pressed the button to supposedly put it in pairing mode. I was going slowly, so I didn’t expect to see my HR.
• In the evening, I took off my HR strap and planned to put it back on in the morning. I suspected that this would put the device to sleep and stop recording my workout (I was right… later).
• The next day, someone else had a mechanical (Di2, and we were fiddling with it in the middle of Kent. Miraculously, my HRM-600 appeared ready to be pressed – something it hadn’t done the previous day. Hmmm.
• So I paired with Wahoo, and it appeared to work.
• Upon arriving home, I immediately went to my iPhone, which found the HRM-600 but couldn’t find a workout. It was completely lost. Many, many HR data points are totally lost. (Starting a short follow-up workout didn’t help it recover.)

This is a bit rubbish. As I said in my review at the time, the HRM-600 has a button that needs to work to start and stop workouts without a smartphone.

Testing Pirelli

I had the latest, greatest Pirelli P-Zero Race TLR SL-R ‘aero’ race tyres. The company’s fastest in the peloton. On the whole, they seem as fast to me as the Conti 111 aero tyre, and I’m sure that independent tests will find the same. For my relatively slow ride, I suppose they made virtually no difference most of the time, although perhaps they did contribute to my apparent faster freewheeling descent speed compared to my fellow riders. I was also using my Cervelo S5 (aero) and may well have had a more aerodynamic position. As one of them said, “You’ve also gained 2 kg, so gravity will make you faster downhill too.” I ignored that argument. Not nice. 🙂 The Pirelli tyre makes good all-round claims on everything (handling, aero, weight, rolling resistance, etc). Well, everything except puncture resistance. The route we did was fairly badly pot-holed (like the rest of the country) and included many small country roads, several in very poor condition. They still were roads, not trails/tracks, but they did have a lot of gravel on them. I was pleasantly surprised not to have got a puncture.

Testing Street X

Polar’s Street X is an urban-lifestyle watch. So if you know any skateboarders or parkour devotees, this is perhaps for them. I did realise that a 200+ bike ride was not its intended purpose, but I only had a bike to hand, not a skateboard.

Battery Test

Including refreshment stops and forgetting to stop the workout, I recorded over 20 hours of GPS cycling time on Street X. The AOD was disabled, but the wake time during wrist movement was excellent, and the AOD’s absence was unnoticeable. I finished with 43% battery life. Polar has a performance training mode claim of 43 hours. So 57% of 43 = 24 hours of expected use (vs 20 actual + use out of exercise). On that rough-and-ready basis, it seems to consume a bit more than would be expected given the Polar claim, but it’s in the right ballpark. Polar asked me to test a few other things, which I’m doing. Part of that included testing the buttons and general wearability.

HR Test

With over 14 hours of cycling HR data, a pattern emerges, but the quality of the comparators (Garmin, Whoop) was highly mixed. The section in the following chart seems representative and shows some agreement between Whoop and Garmin HRM-600. Still, Polar invariably differs from one or both, albeit being roughly in the right zone and avoiding dropouts. The data would appear correct to the wearer with only one device. Inconclusive.

Street X comfort, usability and wearability

It’s a light watch, coming in at 48g for a 45mm-dia case (normal, medium size). It’s very comfy even at night. It does look a bit chunky, but that is the Garmin Instinct 3-like design. Not my thing, but some people like that. The strap IS interchangeable, but it is one of those straps designed to blend in with the case, so that you could buy a generic replacement of the right width, but it might not sit or look quite right. Then came the buttons, which I hadn’t especially noticed were unusual until Polar mentioned them. They do feel different from previous Polar watch buttons and are therefore probably a completely new component. They have a nice action, a little on the soft side but quite pleasant, and it stops just before you might expect a click, which is fine. The button guard around them was perhaps a tad too prominent; it definitely stopped an accidental press, but made an intentional one trickier than I would like, even when wearing thin cycling gloves. Little else has changed with Polar’s on-watch menus, except for a new watchface. I didn’t like it, but that’s a personal preference. As with most other watch brands, Polar could use a better selection of faces to encourage all-day wear.

Takeaway

Polar Street X is solid on battery (roughly matches claims) and super comfy for long wear, but HR accuracy on 200-mile rides is still hit-and-miss. Garmin HRM-600 desperately needs a reliable button start/stop mechanism without the Garmin Connect app. Pirelli P-Zero Race SLR tyres are properly fast, tough enough for the very occasional UK pothole, and live up to the all-round hype. Next time, I’ll convince someone else to pin the coffee stops in the route file.

 

FAQ

How long does the Polar Street X battery last in GPS training mode?

In a real-world cycling test with over 20 hours of GPS recording and AOD disabled, the Polar Street X finished with 43% battery remaining. That suggests roughly 35 hours of total GPS training time, slightly below the 43-hour claim but within a reasonable margin once general smartwatch use between sessions is factored in.

Is the Polar Street X heart rate sensor accurate for cycling?

Over 14 hours of cycling data, the Street X wrist-based heart rate tracked broadly in the correct zone but consistently diverged from a Garmin HRM-600 chest strap and a Whoop band. The data appeared plausible to a single-device wearer, but a side-by-side comparison showed sufficient disagreement to render the result inconclusive. A chest strap remains the more reliable option for cycling HR.

Can the Garmin HRM-600 record workouts without a phone nearby?

The HRM-600 is designed to store workout data independently, but in this test, the strap lost all recorded HR data after being removed overnight and re-paired the following day. The device currently lacks a reliable physical button mechanism to start and stop workouts without the Garmin Connect app, which limits its usefulness for multi-day or phoneless recording.

Last Updated on 11 April 2026 by the5krunner