I recently purchased Garmin Forerunner 245 Music and 255 smartwatch for fitness, activity, and health tracking.
Based on specs, the biggest differences between Forerunner 245 (which was released in April 2019) and Forerunner 255 (released in June 2022) are:
Heart Rate Sensor: 245 has Garmin's Elevate v3 sensor, whereas 255 has new Elevate v4 sensor.
Battery life: 245 lasts 7 days vs 255 14 days, in smartphone mode. 245 lasts 24 hours vs 255 30 hours, in GPS mode.
GPS: 245 has GPS, GLONASS, GALILEO. 255 has additional dual-band (L1 and L5) GPS.
Display and Watch size: 245 has single model. 255 has 255S (smaller version) and 255 (larger version).
Let me just jump into the comparison on what I find as important and significantly different. After comparison section, I will share my background, on why I decided to go with Garmin, instead of Apple Watch and Fitbit. And why I narrowed down to Forerunner models.
(1) Price
Garmin really segment the market with various models. As you go up in price, model has incrementally more features. Best way to compare Garmin models is to use the comparison tool on Garmin.com. For instance, here is the comparison of Forerunner 245, 245 Music, 255, 255 Music: Link to Garmin comparison tool
In terms of value, 245 Music is the best deal with the biggest discount. Note that although I'm comparing 245 Music to 255 (without Music below), the Music capability is not important to me. If it is important to you, then you are looking at $200 difference between 245 Music and 255 Music.
(2) Dimensions
The size is significantly different. Side-by-side comparison is huge, much more than dimensional spec suggests.
245: 42.3 mm diameter x 12.2 thick (from Garmin). Lug height is 45mm. Lug width is 20mm.
255: 45.6 mm diameter x 12.9 thick (from Garmin). Lug height is 51mm. Lug width is 22mm.
I cannot find the lug height for 255 anywhere on the web. So I hope this info is helpful. Lug height is typically the biggest factor if this will fit your wrist. I have a 6.75" or 17 cm wrist. It is quite oval and thick, which means my top surface is actually not as wide, compared to someone with flat wrist. I typically wear traditional wrist watches with 38-41mm diameter and 46-48mm lug height.
Which watch fits you personally depends on your wrist size and preference. 245 is a bit small for me. Looks like a kid's watch when I wear it. 255 is better fit for me.
Forerunner 245 on my 6.75" or 17cm wrist:
Forerunner 255:
(3) Comfort
For me, 255 is more comfortable, as I don't notice it as much on my wrist, even thought it is heavier. 245 feels heavier on my wrist, even though it is a lighter watch. I know. Very weird and counter intuitive. I believe it is because 255 is larger and straps are wider, so weight is more spread out and distributed.
Another reason might be due to the strap. 255's strap is softer, more pliable, and has more stretch. I got much better fit with 255. Once I set the strap, I don't need to change it. On 245, I have to adjust the strap by 1 notch depending on my temperature or activity.
(4) Activity and Data
I wore both watches at the same time. One on each hand.
Heart sensor: 255 heart sensors changes quicker; it will register higher and lower beats faster. 245 takes longer to register increase or decrease in heart rate. For instance, I go from rest to 130 bpm by climbing a hill. 255 immediately showed 130 bpm. 245 was showing 110, 120, 130, back to 115, then 130. So 245 has a lag (around 1 minute) to reach the heart rate.
255 does have a newer sensor (Garmin's Elevate v4) than 245 (Elevate v3). But I don't think this has to do with accuracy/precision or frequency of measurement. I'm guessing it is due to algorithm that Garmin is using. It is almost like 245 is taking a moving average. Maybe this prevent outliers in measurements. As result, in heart rate graph, 255 heart trends show more spikes and details; 245 is smoother.
(By the way, they are on 2 different hands. I don't know if left vs right hand matters.)
In terms of steady state heart rate reading, at rest or during activity, both are basically identical. Majority of time I checked, they have the same reading. Periodically, they will vary by 1-3 bpm. 3 bpm out of 130 bpm is only 2% error. And again, there are hundreds of readings and only select few readings show this small difference. Both are quite precise. Since I don't know have a reference, I cannot say which is more accurate.
For strength activity using free weights, 255 has accelerometer and is more accurate. 255 was dead on, but 245 has intermittent issues with some motions. After 400-500 reps, 255 was off by 1; 245 was off by around 40. 245 was basically correct, except for 2 sets. 1 set with bicep curls; it showed 1 when I did 30. And another set with overhead tricep extensions; it showed 10 when I did 30. But I did other sets with same motion, and 245 worked perfectly. I'm guessing that if I emphasize the motion (or can be dependent on weight), it registers better.
(5) Screen Size
Overall, 255 has better proportions than 245. But there are couple factors: active display size and border.
Active screen size: You can get this from the spec: 33mm for 255 and 30.4 for 245. That 2.6mm does make a big difference in the size. However, this larger screen is not related to readability. For Garmin watch faces, the font sizes are identical on both devices; 255 has more area for additional fields. During work out, the fonts for some data fields are bigger on 255, while others are bigger on 245. For graphics, 255 has more room and appears less crowded. In settings, 245 has larger text than 255. So it is a mixed bag, for older folks like me, who cares about large font and readability. Unfortunately Garmin does not allow user to change the font size.
During activity, the 245's data screen is limited to 4 data fields, whereas 255 can be customized up to 6 data fields. In practice, this didn't matter to me. When I tried 5 and 6 data fields on 255, the fonts are too small. I went back to using 4 data fields. I just add additional data screens, if I need more data. So this turned out to be a non-factor. If you have good eyesight and if you like to cram more data onto single screen, then 255 as the advantage.
Border: There is a border (black ring), between the bezel and the active screen. 255 has a wider border than 245, around 4 mm vs 2.5 mm. If I compare size by side, I can see it. However, it not noticeable in real life usage. Because 255 is a larger watch, this border is kind of proportional to the size. It will be ideal if Garmin can make the active screen area bigger on 255 or reduce the watch dimensions, by keeping the same border size as 245.
(6) HRV (Heart Rate Variability)
HRV has been mentioned as a key indicator of condition, such as feeling normal versus being stressed. I don't have direct experience, and I don't know how useful HRV is. Garmin has to collect baseline for 3 weeks until it will provide assessment on HRV. So I'm not there yet.
Both 245 and 255 measures HRV. 245 uses HRV to estimate the Stress metric, which then goes into the Body Battery metric. But 245 does not provide direct HRV data to the user.
255 has Stress and Body Battery metric. In addition, user can look at HRV measurement and data. So 255 offers more HRV data. To be determined if it is useful.
(7) Customization thru Garmin Connect app on phone
For 255, roughly 90% of the watch settings can be modified on the phone app. This make it a lot easier to customize the settings. For whatever reason, watch faces cannot be customized on the app.
(8) Display & Backlight
First, regarding the display only, not the backlight. Comparing them side-by-side, they are slightly different, but not significant. The viewing angle makes a huge difference to the transflective display, so I'm just moving the watch around to compare. In outdoor light, I do not see any difference. In bright indoor condition (near large window), 255 background is blacker than 245; 245 background looks slightly grayish. This makes the 255 slightly more legible at various angles. In darker indoor settings with artificial light source, 245 has slightly richer colors; 255 colors are a tad lighter and washed out. Just pointing out the differences. Should not matter in actual usage. And I don't know if this is model to model difference, or unit to unit variation.
Regarding backlight, 255 has a lot more options to control the backlight. This makes a lot of sense. Because in bright condition, there is no need for backlight. Backlight is only needed when it is dark; and just dim backlight is sufficient in the dark.
You can set backlight brightness on 255. And it has gesture (raise to turn on) for the backlight. This option can be enabled/disabled during activity or general usage. These Garmin watches do not have ambient light sensor, so they do not know if background is bright or dark. 255 has option to use sunset time to control the light sensor.
In comparison, 245 has single brightness. And backlight turns on with button press, without any additional controls or options.
(9) Lug width and Replacement Strap
Initially, I thought the lug width is important. I prefer leather and nylon over silicone and rubber. Leather is out of the question for exercise watch. I have many 20mm watches, so I have straps that I can use for 245. I only have 1 watch that is 22mm, which is on Nato-like strap, which is not usable on smart watch.
However, Garmin's silicone strap is quite comfortable. Thus far, I don't have any issue with the silicone strap. If needed, I can spend $15-25 to buy a nylon strap.
Background and Experience with Apple Watch
Above was the direct comparison on main differences between Forerunner 245 versus 255. Next, I will talk about my past experience with smartwatches. And why I decided on Garmin and Forerunner series.
I owned 3 Apple Watches (Series 3 42mm GPS, Series 5 44mm Cellular Stainless Steel, and Series 3 38mm Cellular) and Fitbit Charge 4.
When I first got the Series 3 42mm GPS, I wasn't sure what was my need for smartwatch. I had to find out thru usage and trial & error. My experience with AW are mainly as smartwatch, such as notifications, next meeting, travel, dual time zone, etc. AW is a great product. Excellent as smartwatch purpose. I think it should be decent for fitness, but I didn't focus on that feature. Downside is the battery life.
At the company I used to work at, Apple iMessage is standard communication protocol. (I won't say which company, but you can guess which company in the world will use 100% Mac and iPhone). So I get anywhere from 50-300 iMessages each day. Some are individual messages, while other are group chats. So AW was extremely helpful to filter out these messages without having to check my iPhone or open my MacBook Pro.
I had a lot of stress at that job. I went to the company gym regularly (around 3 times a week) to work out and de-stress. Unfortunately, I associated AW with work. So I didn't even bother to use AW for activity and exercise; I just left my AW in the locker when I exercised. In hindsight, I could have used Do Not Disturb.
The company did hold many health and fitness challenges through out the year. There was Close Your Rings challenge once a year. And that required AW. So for that, I did have some experience with AW for activity tracking.
Then I received the AW Series 5 44mm Cellular in Stainless Steel as a gift thru work. It was very nice watch. Looks really sharp and feels very well built. I continue to use it as a smartwatch and did not focus on activity tracking.
I got the AW Series 38mm Cellular for my kid. This was to track location and also as communication device; before the kid got a phone. We had difficulty with battery life. From 8am to 5pm, AW's battery will be completely drained. There are couple reasons. One is that this is 38mm (smaller version), so it has a smaller battery. Another reason is that this AW is on cellular 100% of the time, without iPhone nearby. And it is using the built-in GPS, instead of using the iPhone's GPS. The cellular and GPS drains AW battery, as it cannot rely on iPhone's signal.
My kid now has iPhone, so this AW is just sitting idle. Recently, I tried to use this old AW for fitness tracking. The battery health is already down to 86%. With GPS on, cellular off, and no iPhone, the battery consumption is around 15-30% per hour in activity mode. So basically, after 30-min morning walk and 30-min after lunch walk, I'm already down to 30-50% battery remaining. On weekends, if I take a longer walk of 3 hours, the battery is dead by mid-day.
Couple issues with the battery. One is that user has to charge more often. Another issue is the longevity or battery lifetime. With these smaller devices, the battery lifetime is only around 1-3 years, depending on usage. It is a bit hard to swallow when I spend $400 for a device, and it will only last a few years. So device that uses less battery can also extend the life of the device.
Experience with Fitbit
I changed jobs during Covid. And I got a Samsung Android phone. So I got Fitbit for activity tracking.
Fitbit Charge 4 is a POS. If you need to know what POS stands for, let me spell it out: Piece of Shit. If you are used to Apple product, don't bother with this crap. You will be extremely disappointed. There was issue with comfort, touch screen, display brightness, GPS, phone integration, and advertisement. The positives are battery life and it works as step counter. And it is a pricey step counter.
First on comfort, or lack of. The rubber or silicone strap is very stiff and not comfortable at all. The watch body sits high up above the the wrist. The part that contacts the wrist is 1/4" by 3/4" large. That is it. It is not balanced at all. And the charging pins is designed into that 1/4" x 3/4" area that contacts the skin. This leaves marks and rash on my skin. Extremely poor design.
Touch screen: when the device is in sleep, I can touch the screen 5-10 times, and it will only wake once. Yeah, it is that bad. And raise to wake only works intermittently. Most of time, I just use the physical button. This didn't bother me as much, as I didn't use Fitbit for notification.
Screen: Works fine as fitness tracker, but not usable for smartwatch features. It is next to impossible to see outdoors, either on cloudy days or sunny days. It is just not bright enough. And there is a 2-3mm gap between the exterior glass/plastic and the display itself. This additional layer adds reflection and further reduces visibility.
GPS: It is designed to work with phone's GPS, or fall back to built-in GPS. Issue is that GPS works around 1/2 of the time. Other half of time, it just says GPS signal lost. Often, it is tracking exercise, and GPS signal is lost. So mapping data is next to non-existent.
Phone sync: periodically, it will stop syncing with the Samsung phone. This might be the cause for the GPS issue mentioned previously. Not sure why. I don't even bother try to repeat paring. I just ignore it. Then next day it works again.
Advertisement: Fitbit is trying to push subscription model. Every few days, Fitbit app on the phone will offer "recommendations" and "tips". But these just lead to sign-up for Premium subscription. There is no way to disable these prompts.
Based on my negative experience with Fitbit's hardware, integration, and subscription model, I will not buy another Fitbit.
My Requirements for Smartwatch
My current must-have requirements are very short:
Activity tracker
Long battery life
Other nice to have features are:
Always on screen. After research, I wanted to get transflective screen, instead of OLED. Because transflective screen is always on and has longer batter life; and better value (cheaper).
Buttons instead of touch screen. I had no issues with AW; touchscreen worked great. I had major problem with Fitbit touchscreen. So I'm very hesitant to get Garmin with touchscreen, especially cheaper models. So I ruled out Venu SQ and Venu 2.
Large display. I'm getting older. And larger display is easier to read. However, between Forerunner 245 and 255, font size is not dependent on screen size.
Sleep tracking. I tried this previous with AW and Charge 4. I found that I didn't sleep as well with watch on. And the info AW provided was way off. I know I'm not a deep sleeper. AW constantly report that I only slept 3-4 hours each night, which was way off. Charge 4 did a better job with sleep tracking. But it was uncomfortable, so I only use it for step tracking during the day.
Map for weekend hiking and travel. For weekend hikes, I'm just going to local (city and county parks), so not into the backcountry. I don't need map, but it is nice to have. Also, my family does travel quite a bit. And having preloaded maps will be very helpful to prevent errors. In many countries, there are no trail signs. For instance, we went to Petra in Jordan earlier this year. We took the wrong split and walked 1/4 mile in the wrong way. No big deal, but with family, they complain like hell when error like this happens. And my kid kept on asking "how much further" every 5 minutes. Map will be helpful for travel to keep my stress level down ;)
Altimeter for occasional hiking.
Garmin Smartwatch Comparison
Based on my requirements and nice-to-have features, I shortlisted the following Garmin smartwatches that are around $300 or less:
Venu Sq: I don't want touchscreen. And looks like more smartwatch than fitness watch.
Venu 2: : I don't want touchscreen. And this has AMOLED. Also looks like smartwatch than fitness watch.
Vivoactive 4: Pros are transflective display, has altimeter, and similar price as 245 / 245 Music. Cons are touchscreen and looks a bit too dressy.
Instinct 1/2: Instinct 1 and 2 have excellent battery life, used in smartwatch mode (no activity with GPS). With GPS, the battery life is similar to other models. Con is small gray-scale display. Styling is personal. I kind of like Instinct rugged style. I decided not to go with Instinct because my old eyes are not a good match for small low resolution display.
Forerunner 55: Do not buy this. It is same priced as 245. Get 245 / 245 Music instead.
Forerunner 245 / 245 Music: Considered and purchased. After comparing 245 Music and 255, I decided to keep 255 and returned 245 Music.
Forerunner 255: Considered and purchased. This is the winner in my opinion.
Additional Garmin Topics:
I tested UltraTrac GPS mode: https://jimmy1photo.wixsite.com/blog/post/garmin-forerunner-255-ultratrac
Subsequently, I returned Forerunner 255 and got Vivoactive 4. Herre is my comparison of Forerunner 255, Forerunner 245, and Vivoactive 4: https://jimmy1photo.wixsite.com/blog/post/garmin-forerunner-vs-vivoactive
Pricing:
Here are the Amazon prices as of June 2023. All prices are in USD. The Amazon links are affiliate links.
| | Price (as of June 2023) | Amazon Link |
Forerunner 255 Music |  | $400 | |
Forerunner 255 |  | $317 | |
Forerunner 245 Music | | $195 | |
Forerunner 245 |  | $150 (renewed) |