Garmin vs polar

Everard

Everard

Likes Bikes
I have just upgraded myself to a GARMIN 705and was wondering on the accuracy of the device. I have a POLAR RS800CX. So both top of the line products.

From my understanding
Polar are a specific heart rate monitor company
Garmin are a GPS company.

I wonder why GARMIN want to know bike weight, do they consider body weight? as well as age and heart rate? And for that matter distance and altitude? Who knows.......just thinking out loud.

Does Polar use weight in its algorithym?

I did an identical ride with a mate. We both had Garmins running. At the end of it I burnt 1771 calories. And he only burnt 900. He reckons I am just unfit. But we both had the same average heart rates.

However my bike is 2 kilos heavier and I weigh 15 kilos more than him.
But I am 6 years younger.

So the big test would be to wear my polar strap and the garmin strap together on the same ride. Haven't done that yet. But a bit worried I may get all sorts of interference going on.

Can anyone with any technical worth shed some light on the situation???


OK an update on the situation. I went for a ride last night. both chest straps on. Both monitors were showing identical heart rates. And distance! Which is awesome.. Considering I told the Polar watch specifically what rim diameter I am running whereas the Garmin uses GPS to initially work out the wheel diameter and then tracks it from the speed and cadence sensor on the back wheel.

However after a 1hr test ride. The Polar showed that I burned 690 calories and the Garmin showed that I burnt 500 calories.

But then I checked my profile on the Polar. And my weight was set when i was a lighter 98 kilos. And my Garmin is set for my current weight of 105kilos.

So now I have set both devices to my current weight and I will re try.
 
Pizzaz

Pizzaz

Likes Dirt
Its widely acknowledged that Polar probably has the most accurate HR - energy calculation. The Garmin one almost a guess! As an example... on my Garmin, 90 min, 50km road ride doing intensity intervals = approx 1800 Calories... 50km 3+hr MTB ride over varying terrain = approx 1800 Calories! Algorithm seems to heavily rely on weight & distance.

I've had Polar for ages and have just switched to Garmin (and powertap) and find that the calorie calculation stuff on the Garmin for road riding is inaccurate... but consistently so. So, once you work out what factor its out by then you can just apply that and get some idea of how hard you 'worked' in one workout compared to another. When you're on the MTB... different story though - just doesn't cope with the concept that 50km on the MTB off-road requires more 'work' than a road workout.

I love my 705, paired with the powertap hubs on the roadie and MTB its the best investment I've made in training since getting my polar but I get my energy expenditure from the power figures, not the Garmin internal calculation. I would go so far as to say that if you'd like to track calories burned then you'd almost be better off using a cheap polar to do that (and use the Garmin for everything else).

Good thing though is that as the HR calculation bit in the Garmin is a firmware thing theres always the chance that Garmin might get is somewhere near accurate in a future release of the internal software...
 
spikenet

spikenet

Likes Dirt
Everard said:
I wonder why GARMIN want to know bike weight, do they consider body weight? as well as age and heart rate? And for that matter distance and altitude? Who knows.......just thinking out loud.
Click to expand...
The bike weight is important to figure out energy used, however, its pretty well known the garmin algorithym is not particularly accurate. If you use Sporttracks software there is a plugin that corrects the energy use to something that is closer to real-world.

A Powertap like Pizzaz uses would be the ultimate but us mortals must make do with what we have ;) Anything else but a powertap is always going to be an estimate
 
Everard

Everard

Likes Bikes
Powertap?

At my local bike shop I can only buy the cadence speed sensor. What is this power tap? And how do you get your hands on one.
I downloaded and upgraded the Ascent program and I do like it. As I am a MAC user. Will this be compatible?
 
Everard

Everard

Likes Bikes
Everard said:
At my local bike shop I can only buy the cadence speed sensor. What is this power tap? And how do you get your hands on one.
I downloaded and upgraded the Ascent program and I do like it. As I am a MAC user. Will this be compatible?
Click to expand...
Actually not to worry guys, just googled it. It does look expensive. I think by wearing the polar watch and having the Garmin will be a good combo.
Seeing as that is the cheaper option and I am just happy to be riding recreationally.
 
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