Learn To Read The Radius

Tip #105 from the pages of The Total Motorcycling Manual

radius, increased radius, how a turn is built

Increasing radius, decreasing radius, constant radius—sounds like a geometry class. Pay attention to this course; if you don’t understand how a turn is built, you'll end up with more than just a bad grade.

If a turn curves around at the same rate the whole way through, it has a constant radius. You adjust your speed at the entry, and then you accelerate at the exit. Simple.

If the turn starts out sharp and then opens up wide, that’s called an increasing radius, and it's an even more forgiving turn.

But what if a turn tightens in on itself? Lots of freeway offramps and plenty of mountain roads do so; this turn is a decreasing radius, and it’s what you really need to watch out for. You’ll need to lean more and more if you get into one of these too fast, and that can push you to the edge of the road or over the centerline. With a decreasing-radius turn, you will have to enter more slowly than normal, lean more, or ride a slightly wider line and apply throttle only when the remaining corner is fully seen. On unfamiliar roads, assume every turn is a decreasing radius.