GPS vs Speedo

[mx_ritchie13]

Good morning blokes,
                           I think I know the answer to this before I even mention it but just in case......

Since buying my Garmin 340LM I've used it to good effect on a number of occasions but it was only recently that I noticed it gives me a speed readout, I listen to mine more rather than look at the screen   .

Anyway after noticing it I checked my speedo reading compared with the GPS reading and my speedo is reading about 7mph slower than the GPS. Correct me if I'm wrong but I don't think the GPS can be wrong can it? To my knowledge the dials have never been apart but I might be mistaken.

Has anyone else noticed a difference between the two before?

Ritchie

[MartinW]

I see the same. Approx 7mph different at motorway speeds.

You can get close to 80mph on the clocks without any worries as the GPS will say 73mph.

I trust the GPS as my tacho also reads longer for a trip than it is shown to be in Google Maps.

[Tiny]

Has anyone used a 'Speedo Healer'?


http://www.bikersdiscountstore.co.uk/speedo-healer/healtech-electronics/speedo-healer-v4-pd-18.php

[Hondaman]

My glee speedo reads about 5mph faster than gps at 70mph.
I didn't think manufacturers were allowed to produce vehicles where the speedo underread the true speed?

Anyway, I always fit a Sigma cycle speedo & calibrate it to true sat nev speed

[V-Strom3]

I think the Japanese have a knack for engineering their speedometers to read 10% over the actual speed
Eg at 30 mph you will be doing 27/28 mph, 40 would be 36, 70 would be 63, 80 would be 72
European ones are more likely to be 3 mph over eg 70 would be 67, 80 would be 77.

Hope this helps

[iansoady]

I think Ritchie was saying the speedo read slower. That is not allowed by C&U (I think) - allowable error is - 0% / +10%.

I've never come across a speedo that read slow, although the one in my LR Discovery agrees exactly with the GPS.

[MartinW]

You're right, on re-reading it he does say the speedo reads a slower speed.

Better get him to clarify as if it is that way round then there is some other problem.

Over to you mx_ritchie13

[Hugo Magnus]

I've never come across a speedo that read slow, although the one in my LR Discovery agrees exactly with the GPS.

Do you have oversize tyres on your Disco?

[mx_ritchie13]

Sorry for not getting back blokes my life is just so busy.

Just to clarify my speedo is reading 'faster' than my GPS so if, hypothetically, I was doing 80 according to my speedo my GPS would be reading 73.

I suppose it reading fast is a good thing, rather fast than slow.  

Cheers for the responses blokes.

Ritchie

[MartinW]

That sounds normal and is what mine does too.

[tallpaul]

Same here...

[Theflyingscot]

Same here

[mx_ritchie13]

I thought my bike was just special  

I was actually telling the wife the other day " bl**dy hell the traffic seems to be cruising a lot faster these days!"

Nope just me riding slower!!!    haha