Garmin Vector 3s number "issues"

Discuss light weight issues concerning road bikes & parts.
IvanZg
Posts: 61
Joined: Thu Jan 10, 2019 3:10 pm

by IvanZg

I bought Garmin vector 3s some half a year ago and used it for a while on zwift and my numbers seemed to be consistent. Now I am riding outside for some time and it seems that numbers are all over the place. For example, today I did a ride and rode one of local climbs that is 9,8km long with 6% avg gradient.

Today: Time 39:09 @ 216W avg, 22degC avg
Month ago Time 38:01 @ 194W avg, 10degC avg

I start Wahoo when exit apartment building and do not do any sort of zero offset for power meter. Can that be the reason for numbers differing this much? It’s latest firmware on them and battery was changed some 500km ago. Also crank length is correct and I was a bit lower on the bike then that attempt month ago. Tire pressure was pretty much the same at 7,5 bar at the back and 7 bar in front.

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

You cannot directly compare two different runs up a climb. Was there wind? Was you position different in the heat? Were you carrying additional water? Et cetera. The only way to know for sure is to run a second power meter and then compare the data.

And yes, you should zero your Vectors. Even though auto-zero imignt be enabled, it is not the exact same thing as a manual zero.

by Weenie


IvanZg
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Joined: Thu Jan 10, 2019 3:10 pm

by IvanZg

I forgot to mention that. No wind on both of those occasions. Today I was probably some 1-1,5kg lighter. Also i was lower on the bike for sure as stack on my new frame is 1,5cm lower then on previous bike.
I do not expect to have this numbers precise to 1 or 2 watts. But I was doing pretty much 11 percent higher power then that attempt (the best one this year) and felt disappointed when I finished more than a minute of that time.

bm0p700f
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by bm0p700f

You were a minute slower so 20w less on the slower run is reasonable.

Why assume your Garmin's are all over the place. Why not accept the power reading they produce.

It is possible all this tech does not inform anyone.

You have said it your disappointed with your time so blame the equipment. Your first problem is you care about the time for a climb enough to feel disappointed. My advise sell your vectors and your garmin stop looking at Strava and just go for a ride and enjoy it for what it is.

This ego inflating nonsense of trying to pb and self worth as a cyclist coming from producing respectable numbers is really grating. It's corrosive and off putting.

Why do you ride a bike? If your feeling disappointed your doing some thing wrong. Strip back to basics and figure out how to enjoy it again. Self worth is not found in strava or respectable numbers from a power meter.

IvanZg
Posts: 61
Joined: Thu Jan 10, 2019 3:10 pm

by IvanZg

I did not come here to argue but your post is totally of the subject. I was slower a minute with higher power not lower. Complete weight of the bike and myself was lower so I believe it makes sense to question if something is of with my power meter?

ome rodriguez
Posts: 475
Joined: Fri Feb 24, 2006 9:16 am

by ome rodriguez

I had the same issue with mine. I replaced it with the new battery covers. It was fine for a while then it happened again. Decided to sell mine. Coming from srm, i regret replacing it with a pedal based powermeter

RTW
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Joined: Thu Jun 16, 2005 2:32 pm

by RTW

I have Vectors. I am not in love with them. Yesterday they told me my max power was 25,498 watts.
Your cycling kit is one size too big!

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Leviathan
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Location: Mallorca, Spain
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by Leviathan

A reading like that is the only reason I would love my power meter.
To repeat what THY said, youre not comparing exact things so its very possible both readings were right.

IvanZg
Posts: 61
Joined: Thu Jan 10, 2019 3:10 pm

by IvanZg

I'll repeat same ride on Monday. Weather should be the same, setup as well. So hopefully numbers will show some comprehensive trend. The idea today was to pace myself with 5watts higher than that best attempt to see if I can shave off some seconds. That time I felt it was my limit, today I also felt it was the limit but numbers being higher and time slower makes me question the point of having that thing at all if I cannot use it to pace myself.

Alexandrumarian
Posts: 444
Joined: Mon Mar 28, 2016 6:34 pm
Location: Romania

by Alexandrumarian

When they start showing insanely high spikes, the batteries are low (shouldn't be more than a couple spikes per ride, but enough to ruin the normalized number). When I first got them they used to give a low warning but I haven't seen that in a while. I try to swap them in advance which for me is a bit under 1000Km. Other than this, after getting the updated door I did not have any battery issue so I am happy now.

Do the calibration every time you go out. Have the bike steady against a wall before pushing the button. Although not mentioned in the manual, word is the pedals are better off in a horizontal line (9 and 3:00) when calibrating.

I am fairly anal about analyzing how i do on certain segments and I didn't recall being struck by anything truly odd. Just small things like needing 10 more watts to get the same time on a long climb. Even if wind is not a factor, the 3S has a larger error factor because you might have a fluctuating LR balance. You might not feel it but a few % can throw the number. Also the GPS can have accuracy issues so the times you see on Strava might be a bit off a true stopwatch result.

bm0p700f
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by bm0p700f

Ok I misread your question but given the small power difference and the fact that small changes in conditions could account for the difference I still question your assumption the pedals are at fault.

As pointed out above there many reason why more power can mean slower times. Wind is never truly zero unless you measure on site you'll never know.

If your PM is faulty it's faiy obvious in that it does not work or you get spokes or plainly ridiculous numbers. While it is producing sensible figures, the numbers are the numbers and you either accept them or stop using the power meters. Questioning the numbers your pm produces serves no useful purpose as you simply cannot check and you will always be questioning your PM. I have been down this route which is why I am saying it bluntly.

pafori
Posts: 15
Joined: Thu Sep 20, 2018 1:31 am

by pafori

For the first 2 months, my Garmin Vector 3s were unreliable, some days perfect, other days with spikes and dropouts.

For the past 7 months, they've been flawless. Here's the fix I used, which seems random but it's worked perfectly for me: https://youtu.be/jbK1pkCyW_s

I move my Garmin pedals among 3 bikes. They work great for each. The only maintenance I do now is to change the batteries about once per month when my 1030 tells me the Vector batteries are low.

Sent from my SM-G965U using Tapatalk


RTW
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by RTW

Batteries once a month?!
Your cycling kit is one size too big!

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

My batteries last way more than 1 month, but I am using CR1/3Ns.

by Weenie


GothicCastle
Posts: 234
Joined: Mon Jul 04, 2016 1:52 am

by GothicCastle

IvanZg wrote:
Sat Apr 20, 2019 2:19 pm
I forgot to mention that. No wind on both of those occasions. Today I was probably some 1-1,5kg lighter. Also i was lower on the bike for sure as stack on my new frame is 1,5cm lower then on previous bike.
Pedal-based powers meters can be a little weird; if you have just swapped them between bikes, they sometimes need time to settle in on consistent numbers. A ride with some good hard efforts usually gets the pedals seated well (or whatever is happening) and the numbers are more consistent.

I’m not sure if this is what you’re seeing, but just FYI.

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