Even the cheapest Sigma goes beyond 10,000, probably to five nines, though I don't have a bike with 99,999 in any recognized unit on it. But I do have a bike with over 10,000km on it, and the computer has not reset to zero. The cheap Sigma also has a facility, with a rubberized watertight button between the head and the handlebar clamp where it is protected once set, for setting a start mileage higher than zero on the accumulator when you first fit it, or transfer it between bikes if you use the computer to keep track of services. Around a tenner or maybe a bit over these days. I've been using the cheap Sigma for years and they are genuinely waterproof so they last and last, so that my most recent one is a 509; they've had many upgrades since then, each with a new xxx9 number, but it's basically the same thing: a genuine high-value for a low price. Check the facilities though: you might want something more than a basic five-function bike computer -- I find it tells me everything I want to know, in letters large enough to be instantly read on its sizable scrolling display.
