speedo conversion accuracy

[IIIrd]

when i originally saw the truck she was in km, and has had a mph disc put in for registration etc.
i've checked it against my gps and its 10 mph out, ie when i read 80mph i'm doing 70mph. is it normal for these to be so wildly out?
my cherokee was within 2 or 3 mph

[Hawaii]

hi m8

I also have a 3rd gen but my speedo face is the original (the importer put some sort of leccy gizmo soldered on the back to convert to mph from kph.

Mine also reads out - according to my sat nav when I am really doing 85, my speedo says 93.

Spoke to a mate of mine in the motor trade who told me that it's illegal for a speedo to read lower than "real" speed but ther are no restrictions on how far over it can read - manufacturers usually accept between 5 & 12% out to be OK.

hope this helps

ta

hawaii

[IIIrd]

hi m8

I also have a 3rd gen but my speedo face is the original (the importer put some sort of leccy gizmo soldered on the back to convert to mph from kph.

Mine also reads out - according to my sat nav when I am really doing 85, my speedo says 93.

Spoke to a mate of mine in the motor trade who told me that it's illegal for a speedo to read lower than "real" speed but ther are no restrictions on how far over it can read - manufacturers usually accept between 5 & 12% out to be OK.

hope this helps

ta

hawaii

thanks for the reply,
its kind of nice sittiing there with an indicated 80 you wont get hauled over by the gendarmery, on the other hand, i'd sooner know what i'm doing with a greater degree of accuracy.
any one else with the same experience?

[madbiker]

Your speedo has to be accurate to within 10% otherwise you commit an offence under construction and use laws. If you get pulled for speeding dont use if as an excuse cos you'll probably get done for it on top of the speeding.

[glutes]

see my post on the same subject a week ago, mine's the same. New gizmo and now it's wrong until about 40, then accurate-ish until about 80, then I don't bother going any faster.

Main problem though is the mileometer goes up too quickly, about 5%, which aint good for resale and means my fuel economy is lower than I'd thought!

[gmac11240]

Recently bought a Surf and on 1st decent trip running solo I got a fraction under 30 mpg. Just returned from a caravan holiday 200 miles each way motorway and A roads and got barely 20mpg . Noticed that speedo was out as per gsp but kept doing 60mph and no lorries overtook me. As they are mostly limited to 57 mph ,does this mean that the gps is not accurate.

Graham

[da SLUG man]

don't think that GPS is vary accurate...

the way it works measuring from objects hundreds of miles away, it's bound to be a little out...

when it's positioning on a map it relies on "guessing" half the time to get your exact location... it's noticable when you turn nto a road that runs parallell to another and it puts you on the wrong road until you turn again!...

[andrewlee31]

very easy to check..

pull up along side a renault with a big digital readout on the dash and compare speeds with yours. mines spot on.

and if you grin and start waving at them you get to check it at different speeds..

and there was this blue flashing light.....

[da SLUG man]

very easy to check..

pull up along side a renault with a big digital readout on the dash and compare speeds with yours. mines spot on.

and if you grin and start waving at them you get to check it at different speeds..

and there was this blue flashing light.....

best one is when someone comes along side with their gps saying to turn off the motorway in ** yards... speed up a little so they miss their turning!!.. excellent fun!!

[exmee46]

If they had your speedo apart to change the dial face, then the accuracy is dependent on how carefully they put the needle back in the shaft. Its just a press fit. Mine was under reading by 10mph for this reason.

[IIIrd]

If they had your speedo apart to change the dial face, then the accuracy is dependent on how carefully they put the needle back in the shaft. Its just a press fit. Mine was under reading by 10mph for this reason.

i'll have to check this. the dial is the only thing they changed