Speedo Contradiction

[andrewb]

Hi All,

Was driving along in my RX300 SE II the other day and was getting a bit bored, so I thought I'd play around with the Trip Info & found something wierd. Here's what I did :

1. Waited for a long, straight, even road

2. Put Cruise on and set the speed to 40 MPH (pesky cameras)

3. Reset 'Trip' information on my screen (ie. zero'd)

4. Waited for a bit ...

Average speed on Trip info displayed 35MPH, although speedo was fixed at 40MPH.

5. [Confused] Waited a bit more ...

Same thing!

Which is right, my speedo or my Trip average speed.

Same applied for 50MPH & 60MPH. I guess there would be some math going on inside the Trip calculations but that is a big difference.

Wierd eh?

Andrew

[ColinBarber]

speedos are meant to read over in the UK. The sat nav is more accurate.

[fergy]

Very common for speedos to read higher than you are actually doing...need to have a margin of error for mechanical components, tyre wear etc etc.

GPS much more accurate... pity they cant just feed that info into the speedo.

[Lexusjohn]

My GPS road angel tells me my speedo at a reading of 40MPH is +4MPH and at 70MPH is also +4MPH, so speedo 4miles an hour reading fast! At an indicated 80MPH i'm doing 76MPH still within leagal speed limit on Motorway, so I drive at an indicated 80MPH.

[NickF]

At an indicated 80MPH i'm doing 76MPH still within leagal speed limit on Motorway, so I drive at an indicated 80MPH.

←

I think that you'll find that the legal speed limit is 70MPH

I know what you mean though.

[ColinBarber]

GPS much more accurate... pity they cant just feed that info into the speedo.

←

The speedo is accurate, just been designed to read over.

[shoggy]

On my previous car i had larger wheels/tyres that equaled the discrepancy !

Sat Nav Computer & Speedo nearly matched .