[Closed] Strava accuracy

long list of reasons normally, have a look at the runs and see where they start and stop, some of them stop and start early depending on your GPS.
An update to strava or your phone may have set the GPS to 3s intervals or more but that wouldn't account for much more. I stopped using phones for recording rides etc just because they were killing the battery and moved to a Garmin, seems to work well.

Never had an issue like that. Android app was a bit hit and miss, garmin 500 works a lot better. Have you tried uninstalling the app and reinstalling yet? Without looking at the fit files it's a bit hard to ascertain what the exact issue is.

Tree cover? Did you set your PR's in winter with no leaf cover?

A friend had this on her Android phone (S4 mini), which she used for logging runs etc. in STRAVA. Try this app from the play store, as it sorted her problem out.

https://play.google.com/store/apps/details?id=com.eclipsim.gpsstatus2&hl=en_GB

I used to use it with HTC Hero and never had any dubious GPS readings.

I've noticed a similar issue too. Although I'm not as for as I was I know I'm not twice as slow as before...

Will try to reinstall and see how I get on.

Don't stop at the end of a run, go another 10 meters make sure you've "crossed the finish"

First thing I thought of was tree cover but I set all my PRs in summer as the local woods get unrideable in winter.
Have looked at where they start and finish and they're all pretty accurate, ie not starting still on the fireroad.
Will disinstall and maybe try the app mentioned above but not keen on splashing out on a garmin as the phone used to track fine and the battery is good for a days riding and tracking and streaming music!
Cheers all

Are they DH runs where you stop at the top and bottom. You might be triggered the start of a segment early or not finished it.

I can't see how reinstalling would help. The start and end of the segment can sometimes be way out. The same happens to me and now I just treat strava as an estimate not the law. Most koms I see get are now mostly from lucky wrong gps co-ords rather than being fastest

It's funny how GPS accuracy is always blamed for slower efforts, never the faster ones 😉

jam bo no I checked that they all start a couple metres into the run and finish a couple before.

Haze I expect I've earned a second or two here or there thanks to Strava but never gained over a minute! So I think I'm more owed than owing here

You need to start more than a few metres in and finish more than a few metres out. Solved IME.

You're not as fast as you think you are?

b r thanks for being about the 5th person to suggest that but no I already do that and the segments all start and finish within the trail.

Drac that may very well be the case but what I am quite sure is a sub 2 minute run may very well be a 2.10 or 2.20 or even a 2.30 but certainly not a 4.10. Especially seeming as my PR of 2.06 was set last year on my hardtail having just started seriously MTBing.

Strava & accuracy are two words that can't be used together...

It's about as accurate as guestimating.....

Maybe the answer is to stop using it or take it less seriously. Had a briliant ride yesterday even rode a new jump I hadn't ridden before and ended up getting annoyed over not bettering my PRs on Strava, now that isn't right is it?

Maybe the answer is to stop using it or take it less seriously.

This.

Phone gps is not great. I had the run of my life on a local descent, took the KOM/1100 riders by 4 secs. Within 3 hours someone had knock nearly 30 seconds off it. Bearing in mind it's roughly a 2 minute descent ! Unless he was on a crosser then I think there's a little bit of margin for error.

A wee bit of error adds up when taken both ways - your PR could be faster than reality and your recent runs could be slower than reality. Strava lets you export gpx so if you really cared you could look at the ride in different software (like Adze if on a mac) to confirm the trace or, more likely, see how imprecise the GPS actually is.

Phone gps is not great.

Phone GPS can be just as accurate as a dedicated unit. They all use the same chips.

Look at the segment in detail on strava and see where the time went. Twice the usual time isn't GPS errors, it's probably just triggered the start or the end to soon/late.

m bo - Member
Phone gps is not great.
Phone GPS can be just as accurate as a dedicated unit. They all use the same chips.

No they don't. The chips vary a lot, and many smartphone GPS chips are tweaked to make them less sensitive to small changes. The reason being that far more people use phones for car navigation than tracking bikes in woods. They are adjusted to filter out small changes to help them lock onto roads. This varies per phone and some can be modified by software to increase sensitivity and others can't. Add to that some chips can use Russian satellites (Glonass) to increase the chances of accuracy, though doesn't guarantee it. Some of the dedicated units offer this where many of the older phones may not. Add to that, most phones do not offer barometric sensors. A lot of dedicated units do. This affects altitude which is very poor from GPS alone. And finally, there's the sampling rate. Again phone GPS chips are generally tweaked for car navigation use. They don't need 1s sampling, so sample much lower for less data. Flying through twisty tree singletrack, lower sampling rates is enough to straight line it all.

Anyway, a guide on GPS flaws from Strava (applies to dedicated units also. Some of the issues are more down to segment creation than the device)...

https://strava.zendesk.com/entries/22645314-Bad-GPS-Data-What-Why-How

I think theres a further setting in an android phone to enhance GPS tracking, but uses more battery.

Concur on the taking strava too seriosuly though.

My phone settings for gps are high accuracy which uses gps wifi and mobile networks, however i switch the last 2 off when riding, today ill try with it all on, and start a 2 minute song at the top of the run and see what happens

I realised that Strava is slightly pointless earlier this year when I was going for a PB that turned out to be a bit disappointing. Until I realised that I'd set a PB on a segment that started in the same place but was slightly longer, and on closer inspection, the total time for the longer segment was less than the time strava thought the shorter segment took.

It had the shorter on at something like 2.18 and the longer one at 1.50something. Sometimes, it's just a bit crap. Garmin wasn't much better over similar distances either.

start a 2 minute song at the top of the run and see what happens

start a 2 minute song at the top of the run and see what happens

[img] [/img]

That must be an old pick, lost on me! What film's it from?

I find with most of my PB's on Strava that they have been set with a beneficial wind up my arse, and I have no chance of getting close to them even if I am battering it if I am going into the wind.

But I agree with just use a stopwatch, case closed.
It ain't easy to judge what 2 minutes is...

I don't use strava but have used the lap function on my Garmin 800 to time climbs. More accurate and consistent than anything GPS-based under trees etc can be over 2-8 mins. Can't upload it but don't put my rides online anyway.

chrishc777 - Member
My phone settings for gps are high accuracy which uses gps wifi and mobile networks, however i switch the last 2 off when riding, today ill try with it all on, and start a 2 minute song at the top of the run and see what happens

Wifi and network are used for Assisted GPS. What this does is speed up the initial fix (in technical terms a GPS device has to get the almanac list of satellites and positions, which is downloaded slowly from the satellites or fast by getting it off the network or Internet).

It can improve the precision, but mainly for the initial fix as A-GPS can ping back measured GPS data to a server that can respond with an more accurate fix calculation. Tracking as riding it can't reliably do this sampling every second, so it won't improve accuracy as you're moving, but might avoid the initial position wandering or help if it loses fix and has to reaquire.

You do need to keep data on though, which is an extra battery drain. And then a lot of locations out in the country there's no mobile signal, so not much use.

Mobile also use Wifi and mobile network to get a rough location even if GPS is turned off or no fix available, but Wifi only works where you are near an access point and the access point has a known location, and network will be the location of the nearest cell tower, which could be miles away.

Slight HiJack..

Interested to know if anyones linked thier Garmin with Strava yet (or Endo)

I'm not too sure I want to just in case, but anyhoo's just wondering since they've linked up now whether someones done it and how painfull it was..

I don't care what anyone says, I've regularly seen some wildly inaccurate times recorded on smart phones. Any times on Strava recorded on a phone I discount immediately.

Strava know about the flaws of smartphones and try to compensate. Though there are many inaccuracies with dedicated devices also. A bunch of people I ride with have same or similar Garmin models and yet we can be off in mileage (those that don't use speed sensors) and tracks are a bit out in places, with some straight lined where another less so, or the position is just off by a few feet for a whole trail and segments won't match but the guy in front or behind has a good track. Also seen where segments end and we stand around for a bit, it thinks some are still riding so adds minutes to the segment time, and yet the guy standing next to them it says they finished the segment. Hence segments should be created starting and ending a little into the trail.

bikebouy - Member
Slight HiJack..

Interested to know if anyones linked thier Garmin with Strava yet (or Endo)

I'm not too sure I want to just in case, but anyhoo's just wondering since they've linked up now whether someones done it and how painfull it was..

I've linked Strava. Fairly painless and does work, but it works from Garmin Connect to Strava but not the other direction, so you need to sync with Connect. I don't trust Garmin Express so I don't sync with that, and bluetooth sync never works on my 510, so to work I have to do a manual upload in Connect which is hassle. Also Endomondo still doesn't appear to offer the sync, though it has been promised. It will be more useful once they do as I use both Strava and Endo.

Why don't you trust Garmin Express? Works seamlessly and without any hassle at all here - leave watch switched on, plug dongle into laptop, leave watch sitting near laptop - as if by magic workouts appear on Strava (the only trouble being that I didn't used to upload everything to Strava and it seems more hassle to delete the stuff I don't want on there).

It's a candidate for corrupting ride data on device as it reads it. I was losing rides when I plugged in the device. That said Garmin have just done a firmware update for the 510 addressing corruption on power off, which was my other suspicion.

Still, I read lots of issues with Express in their forums, and it's bloated compared to the simple plug in used on Strava. Or better I just copy the .fit file and upload it so need no extra software.

Cheers for that.

I've not encountered too many problems with Express or Connect but having said that there's always a first time ain't there.
So, I may just have a go later tonight, 810 and fingers crossed at about 9pm.

Thanks..

That must be an old pick, lost on me! What film's it from?

Hudson Hawk. Crap film but the main character sang songs for times as he didn't have a watch.

^^^^ Will have to look that up!

Anyway have just been out and had a great ride, that spurt of rain we had last week has just given the trails that tack they needed! Tried Strava with wifi and mobile networks on and it's even worse somehow, didn't even pick me up on most of the runs. To be honest though reading the comments on here about inaccuracy I think I really was just taking it all a bit too seriously and am not really bothered!

Cheers all!

I have to say that the Strava app on my android phone has been very accurate. Compared to the computer mouted on the bars, accross 3 bikes(which are all based on exact wheel circ), the Strava was within a couple of decimal points on distance and ave speed.

There have been (only a few) Strava fails on my device.....so, i ca`nt complain! 😉

Where do you guys have your phone too when riding? Mines in the very top outside compartment with the fluffy interior for a pair of shades. Found Strava very accurate all things considered.

On road in the rear jersey/jacket pocket in a cloth pouch/plastic bag if wet. Off road in the top of the pack....

GPS distance & speed vs a computer is more accurate if the track doesn't have twisty sections in short spaces and isn't in heavy tree cover. When it does then GPS tends to straight line a bit and then distances can differ. If it doesn't make up much of the ride then it won't differ much, but if it does then it can be out more.

What gets me though is two people with Garmins, no speed sensor so only working off GPS, same trail following each other on the same ride, and both differ by a mile or two!

One jog recorded simultaneously on my iPhone and forerunner 10. Both devices started and stopped together, yet the iPhone version records itself as a total of ~30 seconds quicker, gives me a pace of about 0:30/mile quicker, and adds 0.1 mile in the end.

I used my iPhone yesterday on the Great North Run due to my watch not charging, and managed an extra 0.4 mile on top of last years distance, recorded on my watch.

[img] [/img]

Something else to add that I've just noticed...

I've been uploading to Garmin Connect and letting it sync with Strava recently. The distances shown in Strava are a bit off with those in Garmin Connect. Last ride was 23.08 miles from Garmin (uploaded to Endomondo also and shows same), but Stava shows 21.8 miles. Similar with most of the others I let Garmin sync to Strava. The rides I have in both Connect and Strava prior to that are the nearly the same mileage with Strava just rounding up a little.

So either Strava is doing some magic adjustments or Garmin Connect is messing up the sync to Strava.

It could be Strava actually. Not necessarily messing it up but correcting things.

https://strava.zendesk.com/entries/21278088-How-Distance-is-Calculated

Never trusted strava times after my wife beat one of my times by 4secs even though she was on the back of the tandem. Run a Garmin 810 and wife runs a 610 (watch). Results never the same despite being on the same bike. Mate of mine rode on back of tandem too and he had his IPhone running Strava, again none of the segments where the same times for us both. That was on a road ride too so not alot of tree cover etc.