Unstable speed

Instant pace is very unstable but there are some datafields in the connnect iq store which you can use for this, I think these 2 for example give the user an option to base speed/pace on the last x seconds:

Peter's (Race) Pacer:
https://apps.garmin.com/en-US/apps/23ea0301-30c6-4c33-b4ef-63e2b5394e76#0

Single Run Field:
https://apps.garmin.com/en-US/apps/a520cc32-75b2-4b19-a97d-1079b931dc3d#0

Thanks!

Anyway: I would expect a "factory feature" to fix this issue, not a third-party one.
I don't believe I'm the only one that has this problem, and I can't believe (accept) that Garmin failed in such a basic aspect.

Well, you're not the only one with this problem because it's just inherent to the inaccuracy of GPS...

And getting some average might be an option, but it's considered 'instant pace' and when instant is averaged over so many seconds it's not considered instant anymore (and ppl will complain about not updating fast enough).

And of course you know that your speed is stable right? Doesn’t change with every pedal stroke? Energy input is constant around the full 360 degrees of the pedal stroke? The reality is that we are not as constant as we think we are. Add to that the effects of a small device trying to track satellites thousands of km above your head and you get what you get.

It’s not a problem, it’s a known limitation of consumer GPS.

Agree with philip - it is a known limitation of consumer GPS. Although at most normal cadences, the effect of different power output through the pedal stroke on speed is pretty minimal (it might be different when grinding your way up a steep hill at 40 rpm). :eek: It is generally accurate to about 5m, which means some GPS data points will be ahead of you, and some behind and an erratic instant speed. The Ambit probably applied some averaging so you didn't see it.

The best workaround is to get a speed sensor.

get a speed sensor

Oh yeah, forgot about that. And probably why I've never noticed the fluctuations on my road bike as I've always had a speed sensor. I don't have one on my mountain bike but then my speed fluctuates so much anyway.

And of course you know that your speed is stable right? Doesn’t change with every pedal stroke? Energy input is constant around the full 360 degrees of the pedal stroke? The reality is that we are not as constant as we think we are. Add to that the effects of a small device trying to track satellites thousands of km above your head and you get what you get.

It’s not a problem, it’s a known limitation of consumer GPS.

Come on!
My speed may not be stable, but the fluctuation the device shows (once a second!) has nothing to do with that.

We all agree with, and understand, the limitation of this "parameter", but I would simply expect a valid out-of-the-box alternative, just as some developers did.
Here a comparison 935/Ambit 2 (exactly the same section): I don't know what do you prefer. Personally, no doubts.

I would probably rephrase one of the statements in this thread to: Its a known limitation of consumer GPS, especially those which do not use a SirfStar GPS chipset.

Your Ambit 2 used a SirfStar GPS chipset, my favorite chipset. Older Garmin watches did too. This chipset is quite good at getting a good location even when there is no clear view to the satellites.

Newer Garmin watches like your 935 and my F3 use a Mediatek chipset. It continues to amaze me how little the sky needs to be obscured to get quite noisy location info with my watch. If I walk under a few trees without a foot pod, my speed starts changing wildly. If I walk in a street with 2-3 storey buildings, my path is zig-zag.

You have to live with it, or buy a speed sensor, or buy another watch, or cycle somewhere with a clearer view to the sky, not just above you, but also in the horizon.

Guess it's also a trade-off between battery life and accuracy... (Apart from just going for the cheaper chipset by garmin of course). Getting higly accurate position likely costs more energy/battery. But gps IS just inaccurate in this aspect, few meters off per measurement does crazy things to your instant speed ;)

The binary Mediatek bad vs SirfStar good chip choice thing has been proven to be nonsense by the Suunto Spartan Trainer. It has a Mediatek GPS chip and both fellrnr and the5krunner have commented that in their tests of GPS performance, it’s nearly as good as the class leading Polar V800 (beating many other watches with SirfStar chips) http://fellrnr.com/wiki/Suunto_Spartan_Trainer and https://the5krunner.com/2017/08/18/s...rainer-review/

What the Suunto Spartan Trainer proved is that it’s not the GPS chip that is so much the important thing, but it is the watch form factor, case/bezel/screen materials (all plastic vs some metal bits and sapphire screen) and placement of the GPS antenna; with an antenna bulge below the screen and all plastic case seeming to be optimum. The challenge is that consumers want a watch that looks good and that GPS antenna bulge simply doesn’t fit the bill. So really you have to choose your compromise: get a compact good looking watch and add a foot pod for better pace/distance (if a high level of precision is important to you) or get a less good looking all plastic watch.