speedometer | Ask Honest John

Ask Honest John

Most recently answered speedometer questions

Which is more accurate - my car's speedometer or my sat nav?

What is the most accurate speed indicator - analogue speedometer, digital speedometer or GPS on sat navs?

If I change tyre size will this make the speedometer inaccurate?

If the smaller of the two numbers on a tyre relates to height will remaining on the same size wheel with taller tyre not affect speedo readings?

Speedometer versus car's speed on smartphone - which is more accurate?

When using Google Maps I noticed a 3mph discrepancy between my car speedometer and the phone sat-nav. Which should I rely on?

How accurate are car speedometers?

Some local authorities are proposing that drivers will be given penalty notices for exceeding 20mph limit by as little as one mile per hour. Does this match the level of accuracy of speedometers? I thought...

Can you recommend a speedometer?

I have an old (1976), 24 volt ex-Army Land Rover. The speedometer needle 'waves around', and so is not reliable! Consequently, I have just had to attend a speed awareness course for going 24mph in a 20mph...

Which is more accurate, the speed shown on a speedometer or a sat nav?

On the occasions I use my smartphone as a sat nav, I get a readout of the speed of the car on the screen. It always shows a slower speed than my speedometer by 3-4mph. Since this can make all the difference...

Are there special dispensations for older cars without speedometers when it comes to average speed cameras?

Cars made before 1932 do not have to have a speedometer. Are there any special dispensations for these cars when they pass through camera controlled average speed sections of road? GPS speedos have issues...

Which cars have a large and easy to read speedo?

I have decided to upgrade from my 2005 Avensis to a 2017 Toyota Auris. The new car was fine but the speedo is too small for me to see easily. It is much smaller and buried away in a tube compared to my...