Bike speedo v GPS

General cycling advice ( NOT technical ! )
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The utility cyclist
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Re: Bike speedo v GPS

Postby The utility cyclist » 6 Jul 2019, 12:32pm

Mick F wrote:
The utility cyclist wrote: ............ Otherwise for many trips you just don't need them.
Need.
That's the word.

I'm a bit obsessive, so I need to log where I've been and how far and when.
I've GPS records going back to 2007, and reconstructed ones from before back to 2004 when I got back into cycling after a few years off after leaving the RN.

I don't often follow a route, or even have a page showing any speed or any data. Sometimes I do, especially if I'm on a task or other, but as for stats whilst on the road, I rarely bother. I'm more interested in the maps.

What did you use before, a paper map?
I guess for my locality to 30mile radius I don't need a map, but there's loads of direction and distance signs across the UK so it's easy to navigate no matter where you are without maps. I find it nicer to ride without a device but understand that people want to log their journeys in an easy format.

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Mick F
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Re: Bike speedo v GPS

Postby Mick F » 6 Jul 2019, 12:44pm

The utility cyclist wrote:What did you use before, a paper map?
Generally, the large majority my cycling was commuting.
First to school, and then to work.

There have been times over the eons that I've been out riding for interest and pleasure:
Many moons ago, round the Trough of Bowland or into North Wales - this is back in the 1960s when we lived in Lancashire. Maps is all we had!
I've cycled in many countries whilst in the RN as I took my bikes with me. Maps again, and some of them just tourist leaflets with schematic maps on.
I rode JOGLE in 1994, a LEJOG and Back in 2006 with a road atlas, and a Grand Tour of Scotland, England and Wales in 2008 as well.

I recorded most of that lot. Notes, drawings on the maps, lists etc.
GPS units with good mapping is FAR easier, though if and when I go away next, I'll still take paper maps as well.
Mick F. Cornwall

fullupandslowingdown
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Re: Bike speedo v GPS

Postby fullupandslowingdown » 6 Jul 2019, 12:58pm

Yes, find a measured 10 mile course to calibrate your bike speedo against. GPS will never be reliable especially in city cannons and wooded trials, and the KGB seems determined to interfere at random with satellites just for the fun of it nowadays.

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Mick F
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Re: Bike speedo v GPS

Postby Mick F » 6 Jul 2019, 6:16pm

fullupandslowingdown wrote: ............and the KGB seems determined to interfere at random with satellites just for the fun of it nowadays.
What?
Any proof of this?
Have you had any experience of this?

Can't say any of my ride GPX recordings have been any different to what I would have expected ............ other than the small errors already discussed endlessly on this forum - maps vs online vs GPS.
Mick F. Cornwall

fullupandslowingdown
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Re: Bike speedo v GPS

Postby fullupandslowingdown » 7 Jul 2019, 10:42am

i've stood on top of a mountain, as still as one can in the prevailing wind (Scotland for ever yayyyy)
My trusty Garmin GPS had me moving all over the place, that is to say one minute I'd be a mile away, the next, I'd be back in Fort William. And I'm sure I heard Putin laughing away in the distance (unless I really was lost after eating that last blue jellybaby that I found in the fluff of my pocket....)

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Mick F
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Re: Bike speedo v GPS

Postby Mick F » 7 Jul 2019, 11:57am

I cannot comment, as I've not been on top of a Scottish mountain for quite some years. :wink:

As far as wanderings of a GPS position is concerned, in my experience they are accurate to 7ft outdoors in clear view of the sky and withinn that radius, they're rock sloid. I've never ever had anything "wierd" go on with positioning, and I've had a few different Garmin units as well as a TomTom for the car. TomToms are "lock on road" of course, so sometimes they'll think you're on a different road if two are close together and parallel-ish but never a weird positioning.

Elevation accuracies are a different kettle of fish, but my last Garmin was an Edge 705 and the present one a Garmin Montana, and they can both be calibrated for elevation if you know it. My Garmin Edge 20 I have as well can't be calibrated just like all the others that don't have a barometric altimeter.

I always calibrate my Montana when I'm ready to ride. We live at 222ft above sea level. Easy number to remember!
Mick F. Cornwall

mercalia
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Re: Bike speedo v GPS

Postby mercalia » 7 Jul 2019, 12:01pm

I prefer a cheapo wired speedo eg the Lidl one. I can leave it on the machine in front of the handle bars, since its uses a transreflective display( like the original kindle book reader) will show in bright conditions also have a thermometer. also cheap. is accurate enough. It also dont depend on the ruskies or yanks or whether there is thick cloud cover or I am riding in a forest with thick tree cover

Witterings
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Re: Bike speedo v GPS

Postby Witterings » 8 Jul 2019, 7:50am

fullupandslowingdown wrote:Yes, find a measured 10 mile course to calibrate your bike speedo against. GPS will never be reliable especially in city cannons and wooded trials, and the KGB seems determined to interfere at random with satellites just for the fun of it nowadays.


Have had Map My Ride plot that I've been 300 yds into the sea and back on a ride when I was at least 500 yds inland and at the moment google maps is telling me my house is in the middle of a field approx 300 yds from where it is when it never used to.

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Mick F
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Re: Bike speedo v GPS

Postby Mick F » 8 Jul 2019, 9:50am

This is all very odd indeed!
Google Maps are maps. The public can put names of businesses and tourist locations and stuff on and mistakes often occur, but a map is a map, and satellite views and street views are just that.

How can a house be moved on a map?
Mick F. Cornwall

Witterings
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Re: Bike speedo v GPS

Postby Witterings » 8 Jul 2019, 10:11am

Mick F wrote:This is all very odd indeed!
Google Maps are maps. The public can put names of businesses and tourist locations and stuff on and mistakes often occur, but a map is a map, and satellite views and street views are just that.

How can a house be moved on a map?


No idea but have a look for yourself the dot indicating where the postcode is .... is right in the middle of the field and it didn't used to be

https://www.google.com/maps/place/East+ ... -0.8610967

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Mick F
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Re: Bike speedo v GPS

Postby Mick F » 8 Jul 2019, 12:04pm

Royalmail.com have a postcode finder.
Eleven addresses for that postcode, you select one, and you can see a map where it is.

No doubt Google are approximating and no doubt the approximations vary.
I thought you meant the actual house on the map had moved. :wink:
Mick F. Cornwall

Witterings
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Re: Bike speedo v GPS

Postby Witterings » 8 Jul 2019, 12:18pm

Mick F wrote:Eleven addresses for that postcode, you select one, and you can see a map where it is.


I thought you meant the actual house on the map had moved. :wink:


11 Address's .... but not one of the properties is in the middle of a field and it's "the dot" that's moved (not the house) as it never used to be in the field either but instead sitting on the road approximately in the middle of the range of addresses the postcode includes.

I only noticed the change after I'd sold something in a forum and sent the guy the postcode to come and pick it up and he replied and said ... but your house is in the middle of a field .... I think he thought he'd been spoofed for a while and I'd done a runner with his payment :)

Doesn't explain May My Ride going off into the sea either :)

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RickH
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Re: Bike speedo v GPS

Postby RickH » 8 Jul 2019, 12:50pm

Witterings wrote:
fullupandslowingdown wrote:Yes, find a measured 10 mile course to calibrate your bike speedo against. GPS will never be reliable especially in city cannons and wooded trials, and the KGB seems determined to interfere at random with satellites just for the fun of it nowadays.


Have had Map My Ride plot that I've been 300 yds into the sea and back on a ride when I was at least 500 yds inland and at the moment google maps is telling me my house is in the middle of a field approx 300 yds from where it is when it never used to.

I presume Map My Ride is using your phone. I've found phone GPS can be a bit erratic - if it loses track it will tend to relocate you at the mobile mast you are connected to until GPS location is reestablished.

Here are the maps of my route from a recent ride

Google Maps timeline
Screenshot_20190708-123519.png
Google maps route

Strava (from Garmin GPS log)
Screenshot_20190708-123610.png
Strava (Garmin GPS plot)

Contrary to Google's view we weren't trying out pedalo mode on the tandem. ("go go gadget pedalo! :wink:)

On Google maps & postcodes, I think Google no longer resolve full postcodes (at least not FOC). I found that Google Maps stopped locating our postcode at our house (ours is only us & our semi-detached neighbours) & instead put us in the middle of neighbouring woods. The actual address resolves correctly. I suspect the postcode search now give the centre of the area covered by "AA1 1" rather than the location of the full "AA1 1AA".

rmurphy195
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Re: Bike speedo v GPS

Postby rmurphy195 » 8 Jul 2019, 8:53pm

[quote="The utility cyclist"
What did you use before, a paper map?
I guess for my locality to 30mile radius I don't need a map, but there's loads of direction and distance signs across the UK so it's easy to navigate no matter where you are without maps. I find it nicer to ride without a device but understand that people want to log their journeys in an easy format.[/quote]

Still do use them (paper maps that is).

In my yoof I cycled - and later motorbiked and drove - everywhere using just a rough idea of route numbers and the road signs (e.g. "Home to Hayes, Middx from Castle Brom - Stonebridge, Kenilworth, A41 to Aylesbury or thereabouts, then A413 and you're almost there"). But these days road signs are unreliable, and often send you around bypasses or other indirect routes. They are also often bent, knocked down, or re-pointed(ie vandalised) to show you the wrong way, so my OS map when cycling in unfamiliar territory (and planning a ride) is pretty well essential.
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !