Does anybody else have trouble with their mileage computer?

I've got 2 and they both say different miles!!!

:mad2:

There are lots of variables with the things (tire size, air pressure, microwave and radio interference with wireless, etc) so you can either take the readings with a grain of salt or spend some time on a measured course (ride a marked distance and compare the actual to the computer readings) and adjust accordingly.

Or you can do what I do and not bother with the things.

Unless you are switching back and forth between computers, it should not matter much. It's all relative. If you do 20 miles in x amount of time, your time is the variable to work on. If in reality that "20 miles" was really 19.7 or 20.3 the benefits to your body are about the same.

The key to accurancy is to input the real circumference of the tire with the a specified pressure in the tire and rider on the bike. This is less than the maximum circumference of an unloaded bike as the weight of the rider compresses the tire effectively reducing the circumference. I bet most of us just use the little charts that come with the computer and don't actually roll out the circumference with the tires at proper pressure and with the rider on the bike. When you do that, your mileage travelled, and speed, will show slightly higher than it actually is.

Good point MB1, I won't bother using the things.
I carnt stop looking at them when I shoud be looking at the road!

In reality, using the little chart that comes with the computer will be as accurate as most people need. The difference between between the chart and the actual circumference will probably only equate to a few feet per mile difference.

Personally, not enough for me to worry about.

I agree with Softrider, a 1/8" compression of the tire would throw the speed and distance off between .75 and 1% on a 700mm wheel. That's less than 2/10th mph to most riders which is not huge. However, there are those that are anal about being precise.

Shhh. Don't tell them that their automobile speedometer is likely less precise. They may never drive again. :lol: