Jump to content


Photo

Speed Mph At Odds With My Tomtom Indicated Mph


  • Please log in to reply
27 replies to this topic

#1 catch

catch

    Ford Enthusiast

  • True Ford Enthusiast
  • PipPipPipPipPip
  • 1,306 posts
  • Ford Model: MK2.5 Focus 1.6 Titanium Petrol
  • Year: 2011
  • Location:

Posted 25 March 2010 - 12:04 AM

Hi,

I was belting along the M65 [decided to take look a the MotorPoint Car Supermarket at Burnley]

Not thinking of buying yet [though I do fancy a Mk2.5 Focus, with ESP and cruise control] possibly in a couple of years. Heard some bad feed back on the web about MP, but looking at the set up, there must have been ball park 40 Focus alone to chose from. So they must shift some motors, plus I cannot see a problem buying, if you know what your doing. Just make sure it's not an import, could be problems getting a decent choice of insurance quotes, or problems with the warranty. Check it comes with a full set of keys, only buy a car that is actually in stock at the site you visit so you know exactly what condition the interior is in. Road test it, don't pay extra for valeting or service. Valet it yourself easy enough, and get your local garage to service it, so you now it's done properly. As I reckon most dealers on selling a car just do an oil change plus a new oil filter.

Anyway back to the subject in question, with the speedometer recording 75mph, my TomTom was actually showing 71mph. I reckon the TomTom will be more accurate than the speedometer, making it out by 5.64%

From elsewhere:

Thames Valley Police: "Inaccurate speedos – the legislation referring to ten per cent accuracy went out years ago, modern cars have speedos which are allowed a tolerance that can only read fast not slow. So if your speedo says 30 you will be doing 30 or less but not faster."

Any other sat nav users noticed a discrepancy between the two?

Have something to contribute?

Sign in or register to start a topic...



Sign up to FOC Premium Membership To Remove These Ads

#2 Wizz

Wizz

    Settling In Well

  • New Member
  • PipPipPip
  • 68 posts
  • Ford Model: Focus Zetec S 1.8
  • Location: Leicestershire

Posted 25 March 2010 - 08:28 AM

From elsewhere:

Thames Valley Police: "Inaccurate speedos the legislation referring to ten per cent accuracy went out years ago, modern cars have speedos which are allowed a tolerance that can only read fast not slow. So if your speedo says 30 you will be doing 30 or less but not faster."

Any other sat nav users noticed a discrepancy between the two?


Everyone who uses a SatNav will have noticed the speed difference...........
Car speedo's always read fast....... so you can expect the SatNav to always display a lower ( and probably more accurate ) speed.

#3 catch

catch

    Ford Enthusiast

  • True Ford Enthusiast
  • PipPipPipPipPip
  • 1,306 posts
  • Ford Model: MK2.5 Focus 1.6 Titanium Petrol
  • Year: 2011
  • Location:

Posted 25 March 2010 - 09:25 AM

Everyone who uses a SatNav will have noticed the speed difference...........
Car speedo's always read fast....... so you can expect the SatNav to always display a lower ( and probably more accurate ) speed.


And an even bigger discrepancy between the two, if you monitor it whilst travelling up a long steep hill. :ph34r: As Sat Nav's data works out the distance covered horizontally

#4 Knight Focus

Knight Focus

    Feet Under The Table

  • New Member
  • PipPipPipPip
  • 121 posts
  • Ford Model: 2004 Focus LX 1.8

Posted 25 March 2010 - 10:56 AM

3-4 MPH out is about right. As long as the speedometer doesn't say you're going slower than you actually are you've no problems.

If your speedo was showing, say, 70 and and you were actually doing 75, that would be an issue.

My sat-nav, no matter what I've been driving, has always shown a descrepancy of around that much.

Mike

#5 catch

catch

    Ford Enthusiast

  • True Ford Enthusiast
  • PipPipPipPipPip
  • 1,306 posts
  • Ford Model: MK2.5 Focus 1.6 Titanium Petrol
  • Year: 2011
  • Location:

Posted 25 March 2010 - 11:26 AM

3-4 MPH out is about right. As long as the speedometer doesn't say you're going slower than you actually are you've no problems.

If your speedo was showing, say, 70 and and you were actually doing 75, that would be an issue.

My sat-nav, no matter what I've been driving, has always shown a descrepancy of around that much.

Mike


Yes Mike it would appear speedometers are on average marking up the actual speed by ballpark 5%, on a survey of two :rolleyes:

#6 mjt

mjt

    Too much time on the boards

  • True Ford Enthusiast
  • PipPipPipPip
  • 513 posts
  • Name: Mike
  • Ford Model: Focus Mk2.5 Zetec 1.8HE
  • Year: 2010
  • Location: Cambridgeshire

Posted 25 March 2010 - 11:40 AM

On mine the discrepancy is 74mph on the speedo at 70mph on the TomTom.

#7 Wizz

Wizz

    Settling In Well

  • New Member
  • PipPipPip
  • 68 posts
  • Ford Model: Focus Zetec S 1.8
  • Location: Leicestershire

Posted 25 March 2010 - 11:58 AM

I agree with the majority above...... speedo's are generally 5% fast.
It would follow that Safety Cameras must allow a tolerance of at least 5% ............. otherwise they could be booking innocent motorists. :o

#8 thesilverfox

thesilverfox

    Too much time on the boards

  • New Member
  • PipPipPipPip
  • 725 posts
  • Ford Model: Focus

Posted 25 March 2010 - 12:34 PM

My built-in Satnav won't tell me my speed :P But yes, satnav is much more accurate at a constant speed than a car (which is always set to a higher speed than actual).

Note that a Satnav cannot handle rapid acceleration or braking either - there is always a lag, unless you are picking up numerous satellites (or have A-GPS).

#9 catch

catch

    Ford Enthusiast

  • True Ford Enthusiast
  • PipPipPipPipPip
  • 1,306 posts
  • Ford Model: MK2.5 Focus 1.6 Titanium Petrol
  • Year: 2011
  • Location:

Posted 25 March 2010 - 02:19 PM

My built-in Satnav won't tell me my speed :P But yes, satnav is much more accurate at a constant speed than a car (which is always set to a higher speed than actual).


Who's Sat Nav system is used? The TomTom I have lets you chose from a list of options what data you would like to view on the screen. I just added the compass to the screen yesterday, what I'm I like?

Oh anybody wanting FREE speed camera data for their Sat Navs, you can get it HERE Down load according to what map system your device uses. You will see an instruction document when you open the downloaded zipped file, but its basically just a drag and drip operation. For instance the one I downloaded yesterday was created on 24th February, so quite recent data really. Obviously you get free fixed speed cam data with any new map you buy, but if you don't pay the 19.95 annual subscription, you don't get updates on the TomTom.

I run both the TomTom speed cams and the GB-fix Speedcams from the link provided They don't conflict in anyway. I have set GB-fix to alert me at 400 yards and the TomTom one at 300 yards, to see which picks up what.

#10 mcouchard

mcouchard

    Settling In Well

  • New Member
  • PipPipPip
  • 68 posts
  • Ford Model: 2005 Focus 1.6 Zetec

Posted 25 March 2010 - 02:31 PM

I've noticed a difference on my Garmin in several cars my Megane, my wifes Focus and a horrid Kia Carens hire car my Megane was out the most and the difference gets higher with speed my Sat nav reads 70 at about 75 on the speedo in the Megane (it is 10 years old). After considering it for a while I though it may be setup to accomodate for different speedo viewing angles. As I have noticed a collegues C4 with a digital dash is spot on.

The angle at which you set the seat up and the seat height could in theory effect the angle at which you view the needle on mechanical speedos so perhaps they are compensating (in the Megane I have to tilt the seat base down at the back due to being 6'1", which would affect the speedo viewing angle more than the other cars). Or perhaps I am just giving the car manufacturers too much credit and the mechanical speedo's are just inaccurate.

#11 ford focus edge

ford focus edge

    Too much time on the boards

  • True Ford Enthusiast
  • PipPipPipPip
  • 779 posts
  • Name: Mike
  • Ford Model: Focus ST170
  • Year: 2004
  • Location: Cheshire

Posted 25 March 2010 - 02:35 PM

Sat nav on my blackberry is always slower than my speedo although i am on a 2nd set of clocks so i always assumed they read fast anyway but still i never trust them that much for eg when theres a speedcamera at 30 i always hover around the 27mph mark just incase.


Mike

#12 thesilverfox

thesilverfox

    Too much time on the boards

  • New Member
  • PipPipPipPip
  • 725 posts
  • Ford Model: Focus

Posted 25 March 2010 - 03:03 PM

Who's Sat Nav system is used? The TomTom I have lets you chose from a list of options what data you would like to view on the screen. I just added the compass to the screen yesterday, what I'm I like?


Mine is built-in to the car dash-board as a touch screen unit and integrates all of my other car controls etc (Denso I believe - whatever Range Rover/Jaguar use - same system).

Posted Image

Ford would be contrary to include a speed reading on the satnav that is more accurate than the dashboard and would cause more problems than solutions! Good unit though, as it makes use of TMS to download traffic jams and re-routes as appropriate with no input from me :) (I think newer Tom-Toms have this built in too)

A good friend of mine is a computer programmer for a company that develops GPS software for marine use. He reckons GPS is extremely accurate for projecting speed, save for the aforementioned sharp braking/accelerating etc.

#13 catch

catch

    Ford Enthusiast

  • True Ford Enthusiast
  • PipPipPipPipPip
  • 1,306 posts
  • Ford Model: MK2.5 Focus 1.6 Titanium Petrol
  • Year: 2011
  • Location:

Posted 25 March 2010 - 05:23 PM

Good unit though, as it makes use of TMS to download traffic jams and re-routes as appropriate with no input from me :) (I think newer Tom-Toms have this built in too)


Yes I bought a TomTom GO520 Traffic, which does that, Very cool in that you get the option to stay on the route, or accept its time saving detour. It can be bought as an addon RDS-TMC Traffic Receiver

So how do you up date yours with new maps?

I'm now on the latest map which came with a years free map updates, but I really bought because it has lane guidance and IQ Routes technology on it.The Go series of TomToms does hands free calling, and I can play music I store on it via a SD card through the car speakers, which obvious cuts out whilst it gives verbal instructions. I can also give it verbal voice commands, but it admittedly struggles with a Lancashire come Yorkshire dialogue :rolleyes: Ho, and Map Share downloads are cool, though the square our house sits on has been around since 1991 it did not feature on the TomTom I bought in June 2008. So I updated the correction and its on the latest map now.

#14 thesilverfox

thesilverfox

    Too much time on the boards

  • New Member
  • PipPipPipPip
  • 725 posts
  • Ford Model: Focus

Posted 25 March 2010 - 05:46 PM

Yes I bought a TomTom GO520 Traffic, which does that, Very cool in that you get the option to stay on the route, or accept its time saving detour. It can be bought as an addon RDS-TMC Traffic Receiver

So how do you up date yours with new maps?

I'm now on the latest map which came with a years free map updates, but I really bought because it has lane guidance and IQ Routes technology on it.The Go series of TomToms does hands free calling, and I can play music I store on it via a SD card through the car speakers, which obvious cuts out whilst it gives verbal instructions. I can also give it verbal voice commands, but it admittedly struggles with a Lancashire come Yorkshire dialogue :rolleyes: Ho, and Map Share downloads are cool, though the square our house sits on has been around since 1991 it did not feature on the TomTom I bought in June 2008. So I updated the correction and its on the latest map now.


Yeah add-on is handy, but a pain to route wires and stuff.

How do I update maps? I don't. If Ford think I am spending three figures to buy a newer disc (there's a DVD unit inside the top of the glovebox), they can swivel. It's of most use for motorway junctions and so forth, and these tend not to change a great deal! I think the maps are 05-06, so nothing too bad I suppose. Trying to source the disks from Jaguar/Range Rover units as time goes by.

The most obvious drawback to the unit being unique in that sense! Otherwise it's awesome.

#15 Knight Focus

Knight Focus

    Feet Under The Table

  • New Member
  • PipPipPipPip
  • 121 posts
  • Ford Model: 2004 Focus LX 1.8

Posted 25 March 2010 - 09:50 PM

Oh anybody wanting FREE speed camera data for their Sat Navs, you can get it HERE


Thanks for that, spot on!! I've just bought the official Knight Rider voice, done by the guy who voiced KITT, and it says something like; "I think you better check your digits, we don't want you getting a ticket" when approaching a camera.

Can't wait to test it out tomorrow!! Sad, yes, I know!! :P

Mike

Have something to contribute?

Sign in or register to start a topic...


Not what you're looking for?

Register now, we have a huge community of enthusiasts to answer any questions you might have



0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users