Speedo accuracy?

[ajp70]

I have read the article in Evo about Ollie Marriage doing 215 mph in a tuscan s but, in fact, the GPS recorded it at 178 mph. Is this a flaw of digital speedo read-outs? My Cerb has the conventional clock style which I have assumed was accurate. On the Cerb forum there was a thread about 'how fast have gone' and there were some excellent speeds being quoted.

I have a GPS Performance Box and it does seem to match the speedo but I have not used it at high speed. Not used it much at all really!

[Bluebottle]

ajp70 said:

I have a GPS Performance Box and I.ve not used it much at all really!

What a Waste!...I'll take it off you hands

[bomb]

My speedo in my T350T was absolutely spot on in comparison to the Sat Nav display. No error / difference at all. The digital speedo was very accurate.

I have not yet measured it against my Griff. Being a bit older I think it may not be so accurate.

[Targarama]

bomb said:

My speedo in my T350T was absolutely spot on in comparison to the Sat Nav display. No error / difference at all. The digital speedo was very accurate.

I have not yet measured it against my Griff. Being a bit older I think it may not be so accurate.

Same for my T350 - I suspect all the T cars will be pretty accurate since they use a similar setup.

My Chimaera was a bit optimistic though.

[QuiteQuietCerb]

mine is spot on comparing to both sat nav and road pilot, at high speeds

[Ribol]

bomb said:

My speedo in my T350T was absolutely spot on in comparison to the Sat Nav display. No error / difference at all. The digital speedo was very accurate.

I have not yet measured it against my Griff. Being a bit older I think it may not be so accurate.

It can't always be 100% right due to tyre wear, hence why you are allowed up to 10% error.

[softtop]

Actual speed was a bit less, never trust them especially if they get a bit of dirt on them......

[.Mark]

My Cerb is bang on the money right up to private motorway speeds measured against GPS, The Chimaera over reads by about 10% depending on road speed, it's more accurate at lower speeds.

[Konrod]

softtop said:

Actual speed was a bit less, never trust them especially if they get a bit of dirt on them......

You have balls of steel to take a photo of the speedo at that speed (or even a bit less). Assume you had loaded the film before you started driving....

[verminator]

My cerb speedo is the most accurate of any vehicle i've owned. Dont know how accurate a Road Angel is but my speedo reads exactly the same as that.

[softtop]

Konrod said:

softtop said:

Actual speed was a bit less, never trust them especially if they get a bit of dirt on them......

You have balls of steel to take a photo of the speedo at that speed (or even a bit less). Assume you had loaded the film before you started driving....

The blip was bizarre, I slowed down at the end of a dual carriageway to 40 mph along with the other cars around me, looked at the speedo and it showed I was doing over a 100

When the road opened up again it appeared to work ok, just that it added on the speed.. que the apparent high speed. I think in a MKI you only do that sort of speed if you are feeling really brave and invincible...

[Mark A S]

I can beat that, mine said 200mph once, mind you, that was followed by complete speedo failure, requiring a new speedo sensor, and I had no camera at the time

According to my Tom Tom , my Mk 1 Tuscan’s speedo is 4/5 mph fast……………… However, recently, I was pulled over by a boy in blue, who stated I was doing 80 in a dual carriageway which is exactly what my Tuscan speedo said, but my Tom Tom insisted it was 75, so basically, F—k knows!
I was not prosecuted!

[Bassfiend]

• chuckle*

My '95 Chim speedo is anywhere *UP TO* 30 leptons out at 110 leptons - but which way it's out generally seems to depend on whether you're accelerating or decelerating at the time.

(Taken with the car up on stands of course...)

Phil

[Poledriver]

My cerb speedo is within less than a needles width compared to GPS from 20-160. I just wish the Tacho was as good. On hard acceleration, when I change gear, it bounces around for a good 2-3 seconds before stabilising!

[ajp70]

Bluebottle said:

ajp70 said:

I have a GPS Performance Box and I.ve not used it much at all really!

What a Waste!...I'll take it off you hands

Promised myself I'd use it more next year and take it to events so others can use it. To quote a figure from a stats claim is one thing but to prove it is another. Bit like BHP quotes. Situations when you are demonstrating to a friend your car's 0-60 and then tell them the quote of 4.2 or 4.6 secs, whatever, is actually more difficult to achieve. It's interesting to see what YOU can actually do.

Next year.