Brendan has a post on chases that refers back to one of my old posts on the topic. His solution to the problem involves a straight roll-off, highest result wins, which does simplify it quite a bit. Not too bad a solution.
I wouldn't necessarily want to do it that way, though, because I see races and chases as falling into two categories:
- It's just a quick chase with nothing happening during the run; you just want to get it over with and move on to the next situation.
- It's all about the race or chase itself, and you want interesting things to happen during the run.
I don't think a straight roll-off, either 1d6 as I suggest for ties or multiple d6s as Brendan suggests, really addresses the second situation. It's not about who wins, but what happens to blow the race. Although my old post attempts to address this, I think it's too complicated now. So what I would suggest instead is to divide the faster speed by the slower to get a number of chances per turn that the faster runners can either push beyond their limits or attempt a dirty trick. The slower runner gets only one chance at either.
- Add +1 to speed per "push"
- Roll a d6 per "push": every roll of 5+ means 1 point of exhaustion (Treat as not-fatal damage, recovering 1 point per turn of rest.)
- roll a d6 per trick; every roll of 5+ subtracts 1 point from other side's speed.
- tricks like tripping require both sides to roll a d6 instead of just one; if the opponent's roll succeeds, the trick backfires (but also still affects the opponent if your roll succeeds.)