They all do that sir....

[njw 77]

Just purchased a Road Angel 2, been checking the GPS speed readout against the Cerb's speedo, which seems to be between 3-11mph under the GPS read out. Is this normal? At least it kinda acts as a speed restrictor! No officer, my GPS says I was only doing 110 actually!

(Still dont know how to add the smilies!)

Nick W.

Be Loud, Be Proud & Be Yellow

[DustyC]

: D

The above, without the space, will add the kind of smile induced by driving your Cerb.


: bounce :
Without the spaces will be the feeling afterwards!

[FourWheelDrift]

www.pistonheads.com/gassing/legend.htm

[yellow peril]

njw 77 said:

Be Loud, Be Proud & Be Yellow <g>

Cool!!!!

Congratulations.........you won't be able to find enough smilies now!!!!!

Just add this one to your list.....




...//P//


>> Edited by yellow peril on Tuesday 27th July 12:38

[trooper1212]

It certainly shouldn't be under-reading!

Mine over-reads by about 1-2mph at high speeds and is spot on at all other speeds.

[cerber450]

Mine does the exact same under reads around 3-10mph.
I though it may have been down to it originally having a higher profile tyre on the rear but it doesnt now and it still over reads.

[kojak69]

I think most speedo readouts actually show your speed higher than what it is. I might be right in also saying that it never is the other way. Stand corrected if wrong.
My Road Angel shows my actual speed in my ford focus to be less (4/5mph) than indicated. My cerbera is not as bad.., although not properly checked.

[Rob Dance]

The speedo on my Grand Cherokee reads about 8% slow against the Road Angel.
I never seem to have time to study the cerb speedo that closeley to compare it !!

[njw 77]

Thanks for the link FWD, can annoy away with smilies now

cerber450 said:

Mine does the exact same under reads around 3-10mph. I though it may have been down to it originally having a higher profile tyre on the rear but it doesnt now and it still over reads.

The car does have 18" spiders/tyres, so maybe this is part of the speedo error?



Nick W.

Be Loud, Be Proud, Be Yellow

Ooh, I like these smilies <g>

[J_S_G]

I once calculated that 18" spiders with 40mm profile tyres put the speedo out by about 3% (i.e. 1mph for every 30). Think 35mm profile tyres were just about right.

However, I got done doing 36 in a thirty, and my speedo was reading nowhere near that.

[davetherave1970]

J_S_G said:

However, I got done doing 36 in a thirty, and my speedo was reading nowhere near that.

Dyslexic Speedo displayed 63mph

[gbbird]

davetherave1970 said:

J_S_G said: However, I got done doing 36 in a thirty, and my speedo was reading nowhere near that. Dyslexic Speedo displayed 63mph

So is it not a defence if you can prove that your speedo is out? I was just about to ask where you would stand if you were done for speeding but according to your speedo (which is obviously the reading the driver goes by) you were within the limit?

[j_s_g]

gbbird said:

So is it not a defence if you can prove that your speedo is out? I was just about to ask where you would stand if you were done for speeding but according to your speedo (which is obviously the reading the driver goes by) you were within the limit?

My Tuscan has/had (it's in to have it fixed at the moment) an annoying habit of the analogue speedo dial reading up to 10mph below actual speed. Only spotted this in a 30mph zone lined with speed cameras... it was reading 32, then I glanced at the digital readout which said 42. Had to throw the anchor out sharpish!

Apparently having a mis-calibrated speedo is no excuse. Pah.

[flashheart]

Just had this snag with my delightful Volvo estate. Borrowed a friend's hand-held GPS and got the following results. I drive at the first speed (indicated) to get the second speed (actual). 35=30, 47=40, 59=50, 70=60, 81=70, 93=80, 106=90. Must try Cerbs next.

TTFN

Errr.... those last 2 speeds were by extrapolation officer.