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        General >> Problems >> Speedo reading out
        
(Message started by: macattack on Jul 25^th, 2005, 11:00pm)

Title: Speedo reading out
Post by macattack on Jul 25^th, 2005, 11:00pm

anyone find the speedo reading out on their Scorp?

got a new road angel the other day and fitted it, road angel is reporting the speedo to be about 10% slow (according to the road angel) timed the car over a measured mile and yup it appears to be off.

strange thing is that if i reset the average mph while the cruise is set to 60 on the road angel the electronic averge mph read's 60 even though the needle is saying 67!!

I have check the tyre sizes and have the correct 225-50-16's fitted but even if they were changed and the originals were the 205-55-15's it would be 10% off the other way??

Title: Re: Speedo reading out
Post by Geoff_W on Jul 25^th, 2005, 11:06pm

Welcome 8)

Yes you spotted it, you have been 10% more law abiding than most other motorists.

Interesting variance using cruise, usually the in dash computer shows accurate measurement when reset.

Seems to be a standard undocumented feature across the range.

Geoff

Title: Re: Speedo reading out
Post by Paul B on Jul 26^th, 2005, 7:22am

Yes, Geoff's right. They all do that. So don't worry about your tyre size.

Still, if you stick to what it says on the speedo, at least you won't get a ticket. :-/

Title: Re: Speedo reading out
Post by Fitzy on Jul 26^th, 2005, 2:44pm

You'll find that nearly all cars speedo's show you are going faster than you actually, because this is a legal requirement for all production cars, to read faster than the true speed, so that you do not go over the speed limits unless you intentionally mean to do so. My Navman Sat-Nav also shows a figure about 10% less than my speedo and i have used the SAt-Nav in my Scorpio, a Lincoln Towncar Stretch Limo and a 50 seater coach although the coach was only out by about 2 miles per hour, any vehicle fitted with a tachograph has been speed calibrated for the tachograph machine.

HTH

Fitzy ;) ;D ;)

Title: Re: Speedo reading out
Post by nitram on Jul 26^th, 2005, 3:38pm

Same here, Speedo shows a speed 10% lower than the Trip computer and TomTom.

Title: Re: Speedo reading out
Post by macattack on Jul 26^th, 2005, 9:44pm

cheers all, guess i'll be driving by the road angel or tach from now on!!

Title: Re: Speedo reading out
Post by Dave on Jul 27^th, 2005, 6:33pm

I like the fact it's so out. I do '80' on the motorway, which is really only about 72, and passengers will often say "ooh, isn't it quiet at 80 miles an hour?"

Yeaassss.

D