Login required to started new threads

Login required to post replies

Wrist based GPS vs in cap for swim accuracy
Quote | Reply
I'm curious how accurate folks find their wrist based GPS watches for swim accuracy in terms of distance. I have a 735 and I find that it always is a bit 'short' on most swim courses (I know swim courses are inherently hard to set correctly). I usually put my old 910 under a swim cap, and find it's more accurate. This morning on an easy loop of my local swim hole I got 2100 yards on the 735 and 2350 yards on the 910. This is a difference of 1:40 pace vs. 1:27 pace, which is pretty substantial. In a race it's a lot easier to just go with the watch rather than also put the 910 under my swim cap, and I know it's somewhat irrelevant, as everyone swims the same course on race day.

Blog: http://262toboylstonstreet.blogspot.com/
https://twitter.com/NateThomasTri
Coaching: https://bybtricoaching.com/ - accepting athletes for 2023
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
I might be a cheap person, but I'd never be comfortable during an open water swim if my $X00 watch is anywhere but tightly fixed on my arm.
This kind of makes all accuracy issues less relevant.
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [ask77nl] [ In reply to ]
Quote | Reply
I agree; it isn’t accurate if it’s at the bottom of the lake.
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
But how then would I ensure I am keeping my SWOLF low at the far turn around buoy?!

808 > NYC > PDX > YVR
2024 Races: Taupo
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
I got the 920 and usually swim the same area back and forth. Each side is 750 yards and that's what I normally get. It might be off a yard or two, but it's within 1% of 750 yards.
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
In training I usually put my watch on a buoy that was attached to my waist. Easy to look at during the swim if i wanna know how far ive gone and easy to press lap if i want to!

https://acprestation.se/
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [TriathlonJoe] [ In reply to ]
Quote | Reply
That's my experience with my 920 and 935
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
On the wrist with a 910 or a 920 I find it all over the place on a typical 600m circuit in a lake. Looking at the mapping post swim it's off in the car park, going backwards, etc.

A newer Polar Vantage M seems pretty accurate on the wrist by comparison, and shows a path that actually reflects the true course, and a pretty consistent distance give or take 10 or 15 m.

As per others, I'm too cautious to put it under a hat in case it ends up 20ft under the water.
Last edited by: BobAjobb: Jun 21, 19 15:20
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
natethomas wrote:
I'm curious how accurate folks find their wrist based GPS watches for swim accuracy in terms of distance. I have a 735 and I find that it always is a bit 'short' on most swim courses (I know swim courses are inherently hard to set correctly). I usually put my old 910 under a swim cap, and find it's more accurate. This morning on an easy loop of my local swim hole I got 2100 yards on the 735 and 2350 yards on the 910. This is a difference of 1:40 pace vs. 1:27 pace, which is pretty substantial. In a race it's a lot easier to just go with the watch rather than also put the 910 under my swim cap, and I know it's somewhat irrelevant, as everyone swims the same course on race day.

How do you know it's more accurate? Did you measure the course?

Just swim..... who cares what your watch says.

blog
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [stevej] [ In reply to ]
Quote | Reply
Get this: https://www.platysens.com/marlin/

And leave the wrist watch for the bike/run
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
I put an old 220 Forrunner attached to my goggle strap. It's very accurate and it's old enough that if for some freak reason the strap broke...I won't be heartbroken.

I don't wear a watch during the swim portion of a race.
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
either my 920xt is wildly inaccurate or I can't swim a straight line in OW to save my life.

Oh. nvm.
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
I have a Coros Apex. It's pretty damn accurate on my wrist.
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
 

I have a Fastlane so my distance is always zero which is correct.


.

Once, I was fast. But I got over it.
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
910 on my wrist used to drop signal a good bit. 920 less. 935 never.

Let food be thy medicine...
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [natethomas] [ In reply to ]
Quote | Reply
natethomas wrote:
I'm curious how accurate folks find their wrist based GPS watches for swim accuracy in terms of distance. I have a 735 and I find that it always is a bit 'short' on most swim courses (I know swim courses are inherently hard to set correctly). I usually put my old 910 under a swim cap, and find it's more accurate. This morning on an easy loop of my local swim hole I got 2100 yards on the 735 and 2350 yards on the 910. This is a difference of 1:40 pace vs. 1:27 pace, which is pretty substantial. In a race it's a lot easier to just go with the watch rather than also put the 910 under my swim cap, and I know it's somewhat irrelevant, as everyone swims the same course on race day.

It might just be the 735. I never stop in open water, but I do turn - today my average pace was 2:16, but my average moving pace was 2:02. My pool times are very close to the 2:02 mark.

My race site: https://racesandplaces.wixsite.com/racesandplaces
Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [Jigsy] [ In reply to ]
Quote | Reply
You don’t get to push off every 25 or 50 yards/meters in o/w, so that also may be part of why your /100 splits are slower.

But yeah - GPS accuracy is an oxymoron in open water.


float , hammer , and jog

Quote Reply
Re: Wrist based GPS vs in cap for swim accuracy [Murphy'sLaw] [ In reply to ]
Quote | Reply
I get that, but my point is why it (the 735) gives me an average pace and an average moving pace in ow. I don't stop, so there should only be one pace right? It seems to do something on the turns.

My race site: https://racesandplaces.wixsite.com/racesandplaces
Quote Reply