The S520 was designed for the ultimate crosstrainer or triathlete. The added cycling features let you track performance in all disciplines. The new distance based interval function helps guide you through your toughest workouts on the bike. With the Sonic Link™ technology and the new advanced PPP 4.0 software, you can download your heart rate and cycling data, as well as maintain a training log and even share your data through email. Swim..Bike…Run..Download. New dual position bike mount included. The S520 features a new lightweight stainless steel design for added durability.
Strengths: It makes a good heart monitor for $50 look great.
Weaknesses: Can not load to computer.
Have a good Sony mic, a Creative soundcard and after many attempts I have only been able to download to the watch. The mic has been good enough to record classical guitar
After several attempts over several days I have given up trying to uplink from the watch to the computer.
My email to the company throught their website remains unanswered after 3 day.
Easy to use (never thought I'd say this about a Polar HRM)
Good analysis software
Good customer support
Weaknesses: Requires computer to get HR zone info.
Expensive, especially to equip multiple bikes
Detail info only retained for last ride.
Uplink seems a bit flakey
This is the second Polar HRM I've owned. The user interface is vastly improved over the older models. I've tried many other brands but came back to Polar because the reliability is worth the price.
I wasn't sold on the idea of needing a computer interface. I like the Soniclink because it doesn't require (yet another) special cradle and has proved very robust. The instructions say to remove the watch and point the back of the unit toward the microphone. Sometimes I can get away without doing this but with other microphones it only works if I follow the instructions. The Uplink I haven't gotten to work but haven't put a great deal of effort into that either.
The watch holds basic HR information for six training sessions but the bike detail and calculated Calorie information is only saved for the last session. I guess they wanted to up sell people on their more expensive units because it sure couldn't have cost them but a few pennies more to retain all the info.
The coded transmitters are the only way to go. My son and I can wear separate Polar HRMs on the tandem without interference. I suspect people having trouble haven't read the instructions. You have to have the transmitter working. that means using jump juice, break a sweat, spit (yuck) BEFORE activating the HR function. The watch will seek for a coded signal to sync to. And, as it says in the instructions, you have to be away from other coded transmitters.
I manage to get everything I need out of this watch as an HRM. I ride a lot of different bikes and the cost of equiping all with the speed and cadence sensors would be prohibitive. For the price of either one you can buy a full featured cyclocomputer. Turning off the bike functions also decreases the chances of "ending" your ride and losing infomation.
Strengths: Nice to have a single device for all functions. Wireless HRM, speed and cadence sensors work great. Sometimes they record a spurious max value (which can be edited out on your computer), but are generally great. I've never experienced any signal loss.
Weaknesses: Single recorded exercise session. On long days, no way to piece together multiple sessions, and very easy to stop the watch mid-ride (i.e., at rest stops)
Very fussy storage and data transfer interface, easy to lose session contents.
Buy up or buy down.
Eduarope is wrong. This HRM records only a single session, and it only takes one button press into 'BasicUse' mode to overwrite that single session. I did this last night, so I know. If you're concerned about data retention for download, the S510/S520 is just way too delicate and easy to screw up.
For a lot of purposes, the single-session limitation is no big deal, but if you're out on anything longer than a metric century, and you're walking away from your bike during breaks, or you happen to hit the wrong button in the middle of the day, you then have two options: 1) keep the data you have and don't start the watch again, or 2) blow away the data that's already recorded so you can track the rest of your day's effort.
I personally haven't had a single long ride where I've been able to get all the tracking right for the whole day.
The S720i or the S725 or the S625SX (for runners) all have multi-session recording, and they also wait a long time before timing out (so you can re-stock your supply of Sustained Energy without being neurotic that your watch is about to stop). If you're a distance rider, these two features alone make the higher-end HRMs worth the extra money, especially if you happen to be even the slightest bit absent-minded on arrival at your rest stops.
Soniclink for computer download is fussy and also delicate. In 'Connect' mode, the watch reverts to the time-of-day display fairly quickly, which, if you don't notice, makes it really easy to blow away your data (that's how I did it last night).
Also, if you've never downloaded your HRM sessions, you should. The level of detail for analysis is terrific. It opens up whole new avenues for looking at what you've been doing. Of course, it also makes you angry at you the S510/S520 for being so delicate with your stored data.
Strengths: If you can get it to work for an entire ride the data it captures is very good, that's also assuming you can actually get the data off.
The chest strap is water proof so you can wear it swimming which is a good thing because that's about how wet it has to be to pick anything up.
The cadence sensor has been flawless!
Weaknesses: Somewhat flaky speed sensor, very flaky heart rate sensor. I've got two different chest straps both with new batteries and I cannot get consistent readings.
No trip distance reading, just a cumulative total. It's also heavy and ugly. You step away from the bike for 5 minutes and you're starting over again.
Painful to use, limited functionality, at least the cadence sensor works great. It's a substandard HRM, and an even worse bike computer.
price (relative to other similar Polars)
Weaknesses: sampling rate
I don't think the last reviewer really read the direcions for this monitor. I have both the s510 and s625x. They are both good, but drastically different in price and features.
This monitor will take a maximum of 120 samples. The sampling rate is minimally one sample every 30 seconds for any ride less than 1 hour (more frequent for shorter rides). That's pretty good (the 625x can do 1 every 5 seconds for hours). You can get two hours on a sampling rate of one per 60 seconds on the S510/520. If you are doing the type of training that requires frequent sampling, i.e. intervals, you shouldn't be riding over 50 minutes anyways (and 20 minutes of that is warm up and cool down). Any rides over an hour should not have too much variation anyways so a sampling rate of 1/60 seconds should be fine.
A lot of people have made an issue about losing data (see mtbr.com too). That's misleading. First of all, if you need to take a break from a ride, you can pause the recording. If you need to walk away from the bike, you only need to pause the recording and take the wrist monitor with you so it doesn't time-out. When you come back to the bike, start the recording again and you will not lose anything. Some people complain that they have accidentally hit the record button after a ride and erased their previous data. That's not so easy to do because you have to hit the start button TWICE to start recording and erase the previous record. (The first time only starts reading the heart rate, the second time starts actual recording.)
As for Uplink, it is very finicky. If you have a laptop, plan on amplified speakers unless yours has great speakers built-in. Soniclink, on the other hand, works flawlessly (you will need an external mic if you don't have one built-in). This is good because you will use Sonic link to download data much more often than you will use Uplink to load new exercises to the wrist monitor. However, IR is WAY BETTER. It is literaly 5X faster and there are no compatibility problems. However, we're talking the differnce between a 2 second down-load and a 10 second down-load. No big deal.
As for features, the ability to hold only one full exercise file seems like a bummer. However, even though my 625X will hold dozens, I've never found myself doing anything other than immediately downloading my data after a workout. So that feature has been pretty much a waste.
For the most part, this monitor and the 720/625x are nearly identical except for sampling rate and the ability to add on the polar power meter and use IR for data transfer (and the foot-pod for the 625x). If you are thinking of dumping $350 on the power option, I'm sure you are ready to drop the same on a HRM so that's not a real issue. IR VS soniclink/uplink is a toss up. Soniclink/Uplink will get you by for cheap but IR is faster and easier. Remember, unless you have built in IR on your computer (rare after WIN 95), you will have to dump another $40 on an IR interface to use it! Soniclink/Uplink will work little else than a stock computer.
Features, likewise, are very similar between this monitor and Polar's $300+ units. Basically, this is the best bet for a budget. Ideally, the S720 or S625x will give you more flexibility and conveniece, but not much for the price differential.
As for features, this monitor gives you a lot of data. Plan on a full week just learning how to use it and the software. Then you need to learn how to interpret the data. Plan on buying a book and learning more about that as well. The manuals don't tell you anything about what the data means and how to use it. This HRM is pointless unless you really educate yourself in that area.
Overall, I could do the just as well with this unit (on my bike) as I do with my 625X costing $200 more. But, my fiance uses this one so I keep it and every day wonder why I felt the need to spend the extra $200 on mine.