Even the most frugal rider who resists the urge to upgrade, will still eventually have to spend some money on his or her bike. Things do wear out after all and one of those things that wear of course is your tyres. Much like on a car, it's a gradual process that you don't see happening, a process that can creep up on you unexpectedly. Unlike car tyres though, there's no legal tread limit for bicycles, so forgetting to keep on top of things won't be bringing you a nasty fine any time soon. I for one am happy about this as my departing rear tyre would have been well beyond it's limit, with fabric casing showing through the bald