Sometimes, it might require a little more work. https://haynes.com/en-us/tips-tutorials/how-check-your-speedometer-accuracy The new Sky Drive uses GPS Satellite signals to operate your electronic speedometer. My speedometer is dead! Installing larger rims and tires corrected the builtin error. I've been doing a lot of highway driving lately and have noticed cars riding my … I asked Transport Canada what the standards were for speedometer accuracy. How much money can I get for my dead car? You may be well advised to stick to the number on your speedometer that matches the posted limit. Regardless of the issue, you never want to operate car without a working speedometer. It only reads 35 mph when I am actually going 50 mph. https://haynes.com/en-gb/tips-tutorials/how-check-your-speedometer-accuracy Speedometers are not allowed to read lower than the actual speed of the car, but they are permitted to indicate a value that is 10% higher than the actual speed, plus 4. This may explain why that State Trooper didn't pull you over for going 58 in a 45. Along with the traditional functions as the speed measurement and the classical representations of the round speedometer in the car, this app will also become your trip computer, counting on how many miles you have driven in the current trip, how many hours … When in my car traffic is often going around 80 mph, but when I am on my bike I tend to go the same speed as traffic or faster. I do appreciate your time to read my hub and to share your point of view! A. Doing the calculations using the above equation: We can see that the car’s speedometer is reading a little slow, but since it is off by just over 2 mph it’s probably nothing to worry about. But Is My Speedometer Working Correctly? Go to an interstate or any road with mile posts or mile markers. Ok so I drive a 2006 Pontiac Grand Prix. That your reading of the speedometer was more accurate. Is my speedometer accurate? The response was short and succinct: "Transport Canada does not regulate the accuracy of speedometers. Nissan did nothing to assist my position, my view was they hid behind the ADR. John D Wilson from Earth on November 22, 2011: Hi Au fait. Lots of speedos tend to read fast, and the error gets greater as speed increases. This is especially useful after getting new tires or wheels; even the same size tires can be slightly different diameters if they are different brands. So, chances are if you are looking at 70mph on your car's speedometer, your actual speed is probably closer to 67mph. Which is more accurate, the speed shown on a speedometer or a sat nav? At 70mph the difference between the two can be as much as 5mph. The trouble is that for virtually all of these incidents, I knew how accurate my speed measuring device was but these drivers had no idea whether their speedometer was accurate or not. The best isn't necessarily 100% accurate, it's just the best we can do with what we have to work with. 2. The car takes the recorded rotations, applies a healthy dose of mathematics and spits out a speed. No need for ECU convertors or pulse signal generators screwed onto your transmission. This makes me wonder, is there a way then to test the accuracy of my speedometer? Image credit: Pixabay. To determine your actual speed, you divide the number of minutes it takes you to drive the distance into 60 (the number of minutes in an hour) and then multiply this figure by the distance you traveled. The basic speed app is free but you can upgrade to get built-in maps and a head-up display. This means that if you were actually going 100km/h, your speedometer could read anything from 90km/h to 110km/h and still be correct. Your speedometer may or may not show a number. If the speedometer reading is lower than the actual speed, the speedometer is slow. Older cars will need a different speedometer drive gear installed in the transmission. Off by 30%. - Car and Driver Magazine. When I am going the same speed as everyone else it often reads around 90-100mph. Steve Duckett: Well, if you're charged with speeding and you think that your speedometer might not be accurate, you need to verify that before you go to court. It’s when a speedometer is off by 5 mph or more that you would may want to consider having it checked. How do I know if my speedo is accurate? Speedometer Scandal! One of the biggest signs your speedometer sensor is not working properly is the speedometer will display inaccurate readings or the needle or digital numbers will not move at all on the speedometer display. I recently installed wheels and tires on my pickup with a larger circumference and used a GPS to check the speed reading on the speedometer. It's my guess they do it this way so they meet both US and UK regulations with one standard. 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