Speed Mph At Odds With My Tomtom Indicated Mph

[catch]

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?

[Wizz]

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.

[catch]

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. As Sat Nav's data works out the distance covered horizontally

[Knight Focus]

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

[catch]

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

[mjt]

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

[Wizz]

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

[thesilverfox]

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).

[catch]

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.

[mcouchard]

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.

[ford focus edge]

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

[thesilverfox]

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).

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.

[catch]

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 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.

[thesilverfox]

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 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.

[Knight Focus]

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

[catch]

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

Rather not have to do it, but I only use it on long journeys, and its a 15 second job running it along the bottom of the windscreen. I position the tomtom on the windscreen, just sightly above and to the right of the steering wheel. I would not feel comfortable looking down at a map in the central consul. Mind you, your not supposed to drive constantly looking at the map.

I have an POI on mine that says ...we're near a castle...recorded in my own voice. Oh and if I'm breaking the speed limit I have it programmed it to say......in an child's voice....OOHH. Funny thing is though, if your belting down the motorway over the limit. It kinda susses your intentionally maintaining a speed above the speed limit, so it stops giving me the OOHH warning.

Not that I have down loaded it, but there is even a POI for "dogging sites" for fannys sake :D .

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.

New maps for the tomtom, with a years free map up dates cost £55. I had no sooner bought it, when I remembered tomtom had sent me an £8 voucher in an email ....bugger

[catch]

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

Glad to be of service Mike

[thesilverfox]

Rather not have to do it, but I only use it on long journeys, and its a 15 second job running it along the bottom of the windscreen. I position the TomTom on the windscreen, just sightly above and to the right of the steering wheel. I would not feel comfortable looking down at a map in the central consul. Mind you, your not supposed to drive constantly looking at the map.

I have an POI on mine that says ...we're near a castle...recorded in my own voice. Oh and if I'm breaking the speed limit I have it programmed it to say......in an child's voice....OOHH. Funny thing is though, if your belting down the motorway over the limit. It kinda susses your intentionally maintaining a speed above the speed limit, so it stops giving me the OOHH warning.

Not that I have down loaded it, but there is even a POI for "dogging sites" for fannys sake :D .

New maps for the Tomtom, with a years free map up dates cost £55. I had no sooner bought it, when I remembered TomTom had sent me an £8 voucher in an email ....bugger

There is a second display inbetween the rev counter and speedo as well - where the regular Focus has a small 2/3 line display, all directions are also relayed onto this much larger screen too :) You can make it out in the below image, where 99.9% of Focus's have a blanking plate!

New maps are about £100 on a good day; I believe I can get them for much cheaper though ...

[catch]

There is a second display inbetween the rev counter and speedo as well - where the regular Focus has a small 2/3 line display, all directions are also relayed onto this much larger screen too :) You can make it out in the below image, where 99.9% of Focus's have a blanking plate!

that's OK, yes on mine it's blanked out,

I see you have heated leather seats, I'm jealous, I had em in the S40....

Well it's way past my bed time

catch ya later

[thesilverfox]

that's OK, yes on mine it's blanked out,

I see you have heated leather seats, I'm jealous, I had em in the S40....

Well it's way past my bed time

catch ya later

I lucked out with this Focus. Ford had it under-priced by at least £4000 :) The main screen isn't as distracting as you might imagine.

Either way, goodnight!

[thesilverfox]

I lucked out with this Focus. Ford had it under-priced by at least £4000 :) The main screen isn't as distracting as you might imagine.

Either way, goodnight!

Oh, I did some research. Just tested out the 2008/2009 maps on the Satnav unit, and they are perfect. Ford want £240 for these ... I paid nothing, but want to thank you for reminding me to check :D

[catch]

Don't forget to up date your GB-Fix Speedcams latest free download file is dated 31st March, doesn't time fly.

Latest free one should be out any time soon

[thesilverfox]

Don't forget to up date your GB-Fix Speedcams latest free download file is dated 31st March, doesn't time fly.

Latest free one should be out any time soon

I've signed up with CamerAlert via PocketGPS. Not free, but boy is the database good. I only wanted the cameras on my iPhone, so pretty pleased. Didn't fancy jailbreaking to get free maps sadly!

[jeebowhite]

I hate the inconsistencies between SAT NAV and speedo. Is the difference due to resistance in the wires, and if you have a digital or HUD speedo, is it more accurate?

[thesilverfox]

I hate the inconsistencies between SAT NAV and speedo. Is the difference due to resistance in the wires, and if you have a digital or HUD speedo, is it more accurate?

No it's that most cars are set that way from the factory to indicate a shade faster than what you are actually travelling at. Satnav is generally extremely accurate and more so with assisted GPS found in some devices i.e. Mobile phones etc. If you drive to your speedo you know you are safe from getting caught out in most cases :-)