Are cycle computers accurate?

Question

Are cycle computers accurate?

Answer 1

Generally. I don't think it depends on the price of the bike computer either, as the way bike computers determine speed and distance is very simple. As others have said as long as you enter the wheel diameter correctly they are fine.  

I recently got a Garmin 705 bike GPS, so for fun I matched it up with my Cateye wireless computer. The speed and distance was very similar. On a 50 mile ride the difference was 0.2miles, so this is an error of >1%. Not bad. I did notice that the GPS was a slight bit slower to respond to changes in speed compared to the bike computer.

Answer 2

Actually, many things can influence the accuracy of bicycle computers. First off it must be accurately calibrated to the correct wheel size. Something that 99% of cyclists fail to do. Second, tire pressure affects the computers accuracy, what may be accurate one day, may not be accurate the next. Also the type and age of the tire can affect accuracy. Third, how you ride can affect its accuracy. If you stand up on climbs, it will affect the accuracy.

The computer's readings are for the most part fairly accurate. For general purposes they are close enough. But the next time someone tells you that they hit 60 MPH on a downhill, or they can hold a pace of 25 MPH, take it with a grain of salt. Just because their computer told them so, doesn't mean that it was correct.

Answer 3

Yes - if calibrated properly.  Using the "roll out" method provides a precise match of the computers calculating function.  The roll out method of calibrating measures the outermost diameter of the bicycles tire and references it to a numerical value in the computer.

Because the basic functions of the computer - elapsed time, speed, average speed, and miles traveled are relatively simple - all bicycle computers will have basically the same accuracy.  Cost is driven by features like cadence, heart rate, wattage, and even GPS.

Answer 4

yes. the higher priced ones tend to be more accurate though.