Speedo Again

Best solution, well one solution, if you have a smartphone or a satnav is to use that, my one year old Astra shows 70 on cruise, satnav says 67, better to be under than over (!!).

Mick
Think you have that wrong. Sat navs generally under-read your speed. I know this because in a brand new BMW (where you would imagine the speedo to be accurate) my sat nav always shows about 3 or 4mph less than the speedo. Therefore it follows that if you rely on the sat nav, when it shows you are doing 30 you are more likely to be doing 33!! I reckon you have an accurate speedo in that Astra!
 
I always rely on the speedo, you're right if I relied on satnav I'd have tickets galore! Money is better spent getting the car sorted.
 
Hi all now have a working speedo after fitting new angle drive from Robsport. Cheaper than J R Wadhams and very helpful too. Also the fuel gauge that I damaged has now been replaced and that too is working. Many thanks to clivep6 for supplying replacement.
 
Think you have that wrong. Sat navs generally under-read your speed. I know this because in a brand new BMW (where you would imagine the speedo to be accurate) my sat nav always shows about 3 or 4mph less than the speedo. Therefore it follows that if you rely on the sat nav, when it shows you are doing 30 you are more likely to be doing 33!! I reckon you have an accurate speedo in that Astra!

Why would you imagine GPS systems underread and the your BMW speedometer more accurate than a GPS? You could code a correction factor but why on earth would you make it negative with such obvious safety implications? I've worked with this technology in various projects. For differential/relative measurement, such as speed rather than absolute positioning, it's mm or fractions of mm accurate. The precision of tyre manufacture would be orders of magnitude less accurate for starters.
 
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