I am pretty sure that after reading on this GPS that it really does nothing in the water besides waterproof,
the GPS does not work in the water because can not get the signal, not even sure if the HR works in the water also, basically as good as a stopwatch in the water.
I am pretty sure that after reading on this GPS that it really does nothing in the water besides waterproof,
the GPS does not work in the water because can not get the signal, not even sure if the HR works in the water also, basically as good as a stopwatch in the water.
It seems you are ritght WRT HR measurement while swimming:
Garmin is also announcing a new waterproof, soft-strap heart rate monitor that is streamlined and more comfortable than ever, yet rugged enough to withstand swimming. Though heart rate data does not transmit while underwater, this new waterproof strap means that triathletes can plan ahead by wearing the strap under a wetsuit, shaving crucial seconds off their transition time.
Source: Garmin Forerunner 405CX And 310XT Get Aussie Release Details
The other benefit is the “heart rate based calorie counter”.
Will obviously have to wait until real world reports rather than speculation. However, we have worn our HR straps under wetsuits for the past couple of years without any problem. Maybe waterproof as an issue will appear if worn without the protection of a wetsuit.
Why wouldn’t the device pick up a signal when swimming? Granted it might lose it briefly when your arm is under the water, but then it might also regain that signal when your arm is out of the water.
Talking to a Polar guy the other day he said that Garmin helped them with their GPS and Polar helped them with their new HR band.
My 310XT is on order
is that it? to me it doesn’t seem enough to justify the price premium on the 305… (unless the 305 is getting discontinued to avoid competing with the 310)
I agree. Since I don’t ride with a power meter, 10 hours of battery time is enough for me, and I wouldn’t race with it, I’m not seeing much of a reason to upgrade or buy a 310 over a 305. I love my 305, however.
A barametric altimeter might justify the price increment to me, but the 310 uses a GPS based altimiter just like the 305.
Victor
According to Suunto, ANT+ transmission (same technology as in the Garmin) does not occur through water and even though the watch might be out of the water for a second or two, the strap itself is still in the water and unless they’re both out, no transmission will occur. It might pick up a few beats for backstroke, but I suck worse at that than freestyle.
The only reliable way to get your heart rate under water (with a commercially available multi-sport watch) is to get the Suunto Memory Belt which records all the heart rate info directly in the memory of the belt itself. The data can then be downloaded to a computer after the workout. It will also sync up with a T-Series Suunto watch as soon as you leave the water and start showing you the current heart rate information.
-Mike
Guess the technology in the Timex is different then as that (seems to) give good HR information in the water. But the GPS should still be good.
Cool, I guess Suunto just sweeps other technology under the rug when they’re talking about their own stuff! (I don’t work for them, I just have a T6 that I love).
Have a good one. 
-Mike
I wonder if they have improved the accumulated elevation functionality. I find mine to be wildly inaccurate…usually off by 50%. It seems to do ok with elevation on a given mountain but when you look at the numbers for the whole ride, it is a joke how far off it is.
Upon exploring the features, the multisport mode has a box you can tick that gives you choice of including or not including your transition time.
The 305 does this too.
How do you all know that the HR does not work under water? There is a new strap that is waterproof, wouldn’t that indicate that it DOES work under water?
STJay:
- could you take a picture of the 310XT on your wrist?
- if you have a 305, a size comparison picture would be awesome.
- Does the 310XT have that extra ‘return’ bit that the 305 has (where the antennae is in the 305) or is it just flat?
How do you all know that the HR does not work under water? There is a new strap that is waterproof, wouldn’t that indicate that it DOES work under water?
I’ll speculate that there are two issues here:
-
whether or not the strap will continue to function after repeated / prolonged submersion in water. This may not have been true of the old straps (I don’t recall) but according to Garmin is now certainly true of the new ones.
-
whether the signal transmitted from the new strap is strong enough to go through water and still be detected by the watch. RF attenuates much more quickly in water than in air, and boosting the signal to compensate could really reduce battery life. My guess is that if they had to choose between HR in the water and improved battery life they chose the latter.
STJay:
-
could you take a picture of the 310XT on your wrist?
-
if you have a 305, a size comparison picture would be awesome.
-
Does the 310XT have that extra ‘return’ bit that the 305 has (where the antennae is in the 305) or is it just flat?
- Will do… I will be taking this up to Wildflower. I’ve been on some rides and runs, but no transition. I’ve not seen a manual on it, and am still trying to sort out how to do stuff as simple as moving it from per/mile run pace to mph/kph bike pace.
-
Don’t have a 305 but will try to get one from a colleague to shoot against for comparison. I do have a 405 to compare it against.
-
It’s pretty much flat… no empty spaces dedicated to the antenna. I am very impressed with however the managed to minimize the antenna size and incorporate it.
Will have more, hopefully this weekend. I’ll be swimming with it for the first time in Lake San Antonio… will be VERY keen to give y’all some feedback as soon as I get that going. Will bring my HR strap to see if/how it incorporates as well. Will post some images to my blog in a few days… just scrambling to get ready for the drive to Wildflower and getting my wife ready for her race.
-Jay
Anxious to hear how it went. Love my 305 but have had it fritz a couple times when caught out in a storm. Any idea if the current HR strap will work with the 310?
It’s unlikely this will be any better because GPS has inaccuracies in any position fix. The problem is the watch thinks you’re at, say 1000 ft. at one point in time, then 4 seconds later it thinks you’re at 1005 feet, then 4 seconds later it thinks you’re at 1000 feet again, even if you’ve been on level ground the whole time. It would say you gained and lost 5 feet when in reality you’ve gained nothing. They may have a smoothing algorithm that mitigates this effect a bit but it can only do so much. The 705 has a barometric altimeter that smooths out the fluctuations quite a bit, but it still overstates overall elevation gains over the course of a ride.
The aviation world is moving towards WAAS, which increases accuracy of GPS:
http://en.wikipedia.org/wiki/Wide_Area_Augmentation_System
…but this would still suffer from the same problem of integrating a series of errors (although they would be smaller errors)
This is also the reason the ‘current speed’ readouts on the 305 and 405 fluctuate quite a bit, but the average numbers are usually pretty good because the errors are essentially random and cancel each other out.
The HR transmission problem is with the 2.4 GHz signal they (and Polar WIND and Suunto) use. The older Polar T31/61/whatever used a much lower 5 kHz signal which could make it though water. It’s kinda like the low-frequency bass from a speaker can penetrate the walls, while the high frequency of the tweeter can’t.
Obviously the HRM manufacturers don’t think HR while swimming matters as they’re moving towards the 2.4 GHz transmission.
For what it’s worth, I’ve used my 305 in 16 triathlons over the last two years - and swam with it each time with my HR strap under my wetsuit (even though you’re not supposed to swim with it). The downloaded data shows full HR information with no dropouts. This is a 2 year old unit, and I don’t know what kind of frequency it transmits at. But it did capture HR information reliably during the swim portion of these races.
For me it’s more about getting a better idea of how far I am swimming in open water than worrying too much about the heart rate. If the 310 is able to provide HR information all well and good. That’s a bonus.
My 310XT is pre-ordered. I will shortly have a FR305 for sale.
For what it’s worth, I’ve used my 305 in 16 triathlons over the last two years - and swam with it each time with my HR strap under my wetsuit (even though you’re not supposed to swim with it). The downloaded data shows full HR information with no dropouts. This is a 2 year old unit, and I don’t know what kind of frequency it transmits at. But it did capture HR information reliably during the swim portion of these races.
Did you wrap the 305 at all? I am not terribly concerned with HR info during swim practice more on keeping track of my distances.