Originally Posted by
apricissimus
Once I get over 20 mph, my cheapo Cateye only outputs mph in increments of half miles per hour (20 mph, 20.5 mph, 21 mph, 21.5 mph, etc.). Is there any good reason why this should be?
Sure. It's telling you that it has precision that's good enough to about 1-2%. At 10mph it can give you tenths, but can't pull that off at higher speeds. Basically, it's being honest about its precision rather than giving you an extra digit that isn't real.
I mean, they could give you 10 digits, but it wouldn't mean much.
Not knowing how your particular model works, it's harder to say why it specifically is having such problems. Generally, computers that have integration averaging should get a bit more accurate at moderate speeds, since it has more wheel revolutions to divide the error over.