200 Miles of Testing: Garmin HRM-600, Pirelli P-Zero SLR, and Mallorca 312 Prep

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.

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 all HR data as a single continuous track 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 via the Conenct app, then leave the phone there and see how long the strap would keep recording. Ideally, it would carry over to the following evening, when I would have a full 200-mile HR track as I got back home.

FYI: 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 to unpaired devices and would not pair. I pressed and held the button to supposedly put it in pairing mode. NADA.  The HRM 600 was not visible on new devices.
• In the evening, without touching the button, 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, which I did NOT want to happen. But, hey, testing. (I was right… see 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 paired with their Wahoo – something it hadn’t done the previous day. Hmmm.
• So I paired with MY Wahoo, and it worked.
• 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, and I could try a deleted file recovery, but life is too short to bother.

This is a bit rubbish. As I said in my review of the HRM-600 at the time, it 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.

Polar Street X on the Ride

I wore the Polar Street X on both days, recording over 20 hours of GPS cycling time alongside a Garmin HRM-600 chest strap and a Whoop band. For the full battery, heart rate accuracy, and comfort results from this 200-mile test, see the Polar Street X Review.

Takeaway

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. For the Polar Street X battery and heart rate results from these rides, see the full review. Next time, I’ll convince someone else to pin the coffee stops in the route file.

Polar Street X

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FAQ

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 1 May 2026 by the5krunner

the5krunner

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