Where in a curve should you aim?

[Nehmo]

The road is flat and the pavement is asphalt. Say you're about to enter a curve (on a 2-wheel vehicle, a bike), you want to negotiate the curve as fast as possible, and you have a choice of aiming for the inside of the curve or the outside.
The outer route gives a larger curve radius - meaning less centrifugal force for the same ground speed, but it's the longer route.
The inner route gives a smaller curve radius - meaning more centrifugal force for the same ground speed (but less centrifugal force for the same angular progression through the curve speed *), and the inner route is actually shorter.

*Let's say the curve were a circle. Then you could term speed through the curve in RPM, revolutions per minute. At the same RPM, the outer route has higher centrifugal force.

So in the real world, factoring in friction and the danger of slipping off the road, which path is preferable? Which side of the curve do you aim for when entering a curve?

 

[Dauntless]

In the real world you have to consider the guy on the inside who'll come around too fast and swerve out in front of oncoming traffic, as well as the guy on the outside who'll cut too tight in front of oncoming traffic.

So the normal racing line would be to set up to the right side of a left hand turn, then begin your turn while you're still on the straight away and reach that dividing line. If you're going fast enough, there won't be a car coming up behind to hit you.

Seems I'm giving you all sorts of reasons to forget about what you're thinking and just ease your way safely along the outside. Being careful to stay out of the way of even a car on your side of the line that corners too hard and slides out. These are real world concerns. The banked turn of your link isn't much real world.

http://www.miata.net/sport/Physics/05-Cornering.html

http://www.drivingfast.net/techniques/racing-line.htm

 

[doctorGONZO]

Nehmo, are you serious?

Many years ago today, on my Triumph TR6, I figured out that

1. I really, really, disliked the concept of going off the pavement unintentionally; I set up for the innermost path available so that if I laid it down or it started to slip, I had the most room to correct it and recover it.

2. I discovered that my Trumpet got glued to the road when I went in low and then nailed it coming out. Go in low, nail it, and zoom out like on a rocket. Worked for me. Scared myself a few times but never lost it.

Results may vary. Try at your own responsibility.


GONZO

 

[liveforphysics]

http://en.m.wikipedia.org/wiki/Racing_line

 

[bobc]

"The racing line" is for tracks. It has no place on public roads. You should be thinking more about maximising visibility round the bend than maximising speed round it.
I reckon you should be able to stop in somewhat less than the distance you can see......

On track cornering lines vary due to circumstance. With no-one else around you do the accepted "racing line". Do that with someone following you & they will nip up the inside, bag the apex & overtake you. All good fun

 

[dogman dan]

You won't have higher g's by riding the outside edge. The tighter and more abrupt the turn, the higher the g's, including the possibility of losing traction for a laydown. So the racing line that flattens and lengthens the curve the most will be the least likely to lay you down. It's when the change of curve is abrupt that you press your luck on the tire holding the curve. So try to corner smooth, rather than turn corners into a square with two corners. The worst is you are inside, then have to swerve wide for that guy with a wheel on the stripe, then cut back in to stay on the road.

Of course, any loose gravel can throw you down, so following the clean swept stripe cars put in the curve can be the safest line. Edges can be gravel traps.

In the situation in the picture, ( where you are driving into the picture on the RH side) it's not wise to cut too close to that yellow line. Oncoming cars my not be entirely on their side. In this pic, you can't see for sure it's clear till pretty late.

So in a car, you pretty much follow the lane in that case, unless you can see around the corner fully. On a bike or motorcycle, you can still take a racing line within your lane, which flattens the curve some. Start wide, hit the apex tight, then swing wide again. But without getting too close to that line, or finding loose gravel that might be along that stripe.

If you can see around that corner, and no cops will see you, and there is not a motorcycle passing you, then you can take a racing line around the corner using both lanes. In a car, you might even choose to drop an inside wheel into the ditch, for some extra camber on the corner.