The brand name Garmin is almost synonymous with cycling computer, and Garmin enjoy a healthy chunk of the sports watch market too.

The Forerunner 55 may sit towards the entry-level end of Garmin's fitness and running watches, but don't let that put you off. As any cyclist who's familiar with their excellent cycling computers like the Edge 130 Plus will know, "entry level" for Garmin is a fairly high bar.

Boasting GPS tracking, a heart rate monitor and the ability to track and display metrics including speed, distance, VO2, calories and more, the Forerunner 55 is packed with useful tech.

But can this lightweight smartwatch replace your cycling computer?

Time for a run? The Garmin Forerunner 55 is an ideal accomplice.
Time for a run? The Garmin Forerunner 55 is an ideal accomplice.

I've been using the Forerunner 55 over the past 10 months as an accomplice to my secret running habit.

Yes, running. What started out as a way of grabbing a quick blast of fresh air and endorphins on days when I hadn't time for a "proper" workout, ie a bike ride, has steadily developed into a minor addiction in its own right.

It began innocently enough: a Park Run here, a lunchtime jog there, but always as a second-rate ancillary to my true love, cycling.

Somewhere along the line, this flirtation developed into something more. I found myself enjoying running, even starting to suspect - plot twist - that I might actually be better at it than riding a bike... and I lay at least some of the blame for this at the feet of the Forerunner 55.

In my defence, cyclists running is a thing these days. You may recall Tom Pidcock posting a ridiculously fast (albeit dubious) 5k time, or Adam Yates running a sub three-hour marathon... and who can forget the time Chris Froome famously jogged up Mont Ventoux on the 2016 Tour de France?

I still prefer cycling, but the knock-on effects of all this running about have been largely positive. I've lost a couple kilos of winter ballast (boosting the all important power-to-weight ratio), and it's a good cardio workout. Not to mention the feel-good factor of posting new PBs on Strava, something that becomes increasingly difficult to do on the bike when riding familiar loops over and again.

The Forerunner 55 has proven an ideal companion on these jogs. It's small and lightweight (just 37g), and very simple to use. Pop it on your wrist, hit the "start' button, and go.

Operation is via five physical buttons either side of the screen (three on the left, two on the right). The watch body is 42mm across, and the actual display is 1.04" (26.3mm) in diameter with a resolution of 208 x 208 pixels. I find it small enough to be unobtrusive, while remaining easy to see details at a quick glance while on the bike.

You can customise the watch face and data displays both on the watch itself and via the Garmin Connect app. As an example, the default setup will scroll through VO2 Max, my weekly activities, current heart rate, body battery, daily steps, notifications, weather, suggested workout, and activities (number and type) over the past seven days.

Daily steps and body battery are among the metrics tracked by the Forerunner 55.
Daily steps and body battery are among the metrics tracked by the Forerunner 55.

The ease of use makes it ideal for the running-curious cyclist, especially if, like me, you may be reluctant to invest too much time learning how to set up and operate a piece of new, non-cycling-related gadgetry.

For bike rides, customising the display to show your preferred in-ride metrics is quick and simple on the Forerunner. The screen can display up to four data fields at once: I've set mine up to show ride time, distance, current and average speed, but you can also select heart rate and various other metrics.

While the amount of info you can view during an activity is limited compared to a dedicated bike computer, the Forerunner 55 has GPS tracking, so at the end of your activity you can upload the ride to Strava, Komoot or your preferred app and see everything there. I've found it locates a satellite for a GPS fix very quickly when starting an activity, typically within 5-10 seconds.

While smaller than a full featured bike computer the display shows useful info.
While smaller than a full featured bike computer the display shows useful info.
It doesn't offer navigation (although plenty of Garmin's other watches do) but you do get heart rate data, which of course is useful if you're training. During a run it also tracks your cadence (steps per minute) and estimates your VO2.

I've been particularly impressed by the battery life. Garmin claim approximately 20 hours in GPS mode, which is much longer than you'll get from most cycling computers (around double what you could expect from the Edge 130 Plus for example).

For my usage, maybe 2-3 runs of around an hour each over a week, I can go a couple of weeks between charges. I normally only wear the watch for activities, but if you do wear it constantly Garmin will reward you with a rich set of data to pore over, from analysing sleep and heart rate through the day to steps and even suggesting workouts based on your perceived stress level and freshness.

Freshness is tracked by what Garmin call your "body battery", a neat concept that scores your energy reserves out of 100. Your battery score will recharge during periods of sleep or inactivity, while strenuous activity will deplete it. The accuracy I guess improves the more you wear the watch - it's less useful if you leave the watch at home on bike rides, for example, as Garmin doesn't then have a full picture of your activity levels through the day.

The watch will even suggest a daily activity for you based on your energy levels and recent workouts.

Other useful features on the Forerunner 55 include the ability to control music on your phone from your watch - meaning you can skip tracks and adjust volume without digging your phone out of its pocket while on the move - and receive notifications of messages and phone calls.

Many higher-end cycling computers also offer this feature of course, but if you're out running it's handy to have these on your wrist.

You can pair the Forerunner with your phone to control music and receive call and message notifications.
You can pair the Forerunner with your phone to control music and receive call and message notifications.

I've been really impressed by the Forerunner 55 - much more than I expected to be, in all honesty.

As to whether it could replace a cycling computer, for many shorter rides the answer is yes, it absolutely could. If I'm just nipping out for 90 minutes on a regular loop, I really don't need a full-fat bike computer sitting on the bars to tell me how far I've gone or my average speed.

In a way, it's actually preferable to be liberated from the screen while riding, secure in the knowledge that the Forerunner is tracking the vital details to upload to Strava later (my need for validation unfortunately remains undimmed, but at least I can save it for the post-ride coffee).

The only real features it's lacking relate to navigation, and for longer rides - including sportives - I would still want to have the bike computer and its full suite of bells and whistles to hand.

But for many people the Forereunner 55, despite its lack of navigation, will be ideal. For cyclists who run, or vice versa, the Forerunner 55 is a viable alternative to a cycling computer that allows you to track both rides and runs complete with metrics including GPS tracking, heart rate, speed and distance - and all with an impressive battery life and lightweight form factor.

If you like to monitor these metrics on a screen during an activity, or need to follow a route, then a dedicated bike computer is still a better choice. But for more casual use, the Forerunner 55 is a versatile, feature-packed and surprisingly sophisticated bit of kit.

Just be warned, running is surprisingly addictive. Don't be surprised if, after a few months, you find yourself eyeing up entry to a duathlon or two...

Garmin Forerunner 55, £159.99 from