How Do You Ride A Negative Camber Corner?

[Spaghetti]

I was used to hesitate on negative camber corners because of the added lean angle due to the skewness of the asphalt. My corner speed in turn 10 at Thunderbolt is particularly low (50Mph last time I checked), because of that little negative camber entrance.

 

Until somebody explained to me that in negative camber turns the inside knee touches the asphalt sooner than on flats, since the inside is elevated relative to center of the track. In other words, using the knee as a reference point will play exactly the same way than on a flat corner, except the whole plane is tilted.

 

Sounds like a valid point. Yet I've seen a few crashes on negative cambers. How do you ride them?

[rchase]

Nobody's commented on this so I'll make a mess of it. Fair warning this answer could be completely wrong.

 

How do I approach off camber corners? With caution and a bit of extra thought. Off camber turns often have less traction due to the angle of the track and the direction of the weight and grip of the tire.

 

On a corner that has an off camber entrance but normal exit do you think the "slow in fast out" method might be helpful?

[khp]

Off camber turns often have less traction due to the angle of the track and the direction of the weight and grip of the tire.

 

Chase, you can replace that "often" that I highlighted with "always"

Everything else equal, an off-camber turn will have less traction available to a neutral or positive camber turn. It's down to physics.

 

BTW, it's similar to going through a (large) turn that has positive camber in the middle of the corner, but then flattens out to be neutral.

[Spaghetti]

One year later I can only confirm what rchase and khp wrote. I've seen too many "explainable" crashes on negative camber and now feel like even the smallest positive camber brings stability to my corner lines. This may be one of the most overlooked subjects in advanced riding skills as far as I could gather in three years of track days.

 

It's hard to tell how much each little degree of camber improves the bike stability. There could be something with the bike weight displacement or the projection of the track plane on the wheel base that improves grip more than expected. Or maybe subtle camber changes are the result of fast riders carving the correct line on the track? Would love to understand more this subject.

 

Also for some very high degree of camber, like the Daytona banks, the camber benefit might be offset by the weight of the bike on a much higher lean angle. In other words, traction improves significantly for small degrees of positive camber but only up to a certain lean angle.

[BikeSpeedman]

Also for some very high degree of camber, like the Daytona banks, the camber benefit might be offset by the weight of the bike on a much higher lean angle. In other words, traction improves significantly for small degrees of positive camber but only up to a certain lean angle.

 

You sure? Think about the silidromes and wall of death. With enough speed, you can ride a completely vertical wall with zero risk of losing traction. All of the force from the tires goes directly into the surface so there's no force trying to slide the tire across the surface.

[Spaghetti]

 

Also for some very high degree of camber, like the Daytona banks, the camber benefit might be offset by the weight of the bike on a much higher lean angle. In other words, traction improves significantly for small degrees of positive camber but only up to a certain lean angle.

 

You sure? Think about the silidromes and wall of death. With enough speed, you can ride a completely vertical wall with zero risk of losing traction. All of the force from the tires goes directly into the surface so there's no force trying to slide the tire across the surface.

 

 

Not sure, was trying to add one more observation on camber riding. I agree high speed can glue the bike to the surface.

 

Another thing I've noticed is that elevation changes alters the braking distance significantly. Uphill is easier to manage, but slightly downhill end of straights have a surprising effect on braking power.

[Jasonzilla]

There is both a magnificent bank and off-camber corner on Chuckwalla in California. The thing to remember about off-camber corners is that before you even turn, you're riding at a lean. If it's, say, a six degree angle and someone is wanting to get on the throttle, when the rider believes they're at a certain spot picking the bike up in regards to the typical horizon, they can easily forget they're actually still more leaned over than normal and be giving too much throttle for their actual amount of lean. Some don't think to adjust for the change in traction limits for where they're at. The same goes for braking into the corner.

[Lnewqban]

 

Not sure, was trying to add one more observation on camber riding. I agree high speed can glue the bike to the surface.

 

Another thing I've noticed is that elevation changes alters the braking distance significantly. Uphill is easier to manage, but slightly downhill end of straights have a surprising effect on braking power.

 

 

With negative camber, a little portion of the weight of the bike adds up to the sliding out (centrifugal) force of cornering.

At the same time, the normal force that creates grip between rubber and asphalt becomes a little smaller.

 

https://en.wikipedia.org/wiki/Friction#Normal_force

 

The opposite happens for curves with positive camber.

 

There are other steering effects induced by changes of camber:

http://www.soundrider.com/archive/safety-skills/coming_unglued.aspx

 

As for braking uphill and downhill, again, a portion of the weight of the bike adds up to the braking force (uphill) or reduces the effect of brakes (downhill):

 

http://www.soundrider.com/archive/safety-skills/RS-braking3.aspx

[Jaybird180]

Camber, positive or negative is a track-designers little trick they play to add a little spice to a corner. It adds a bit off angle surface with the center of the contact patch of the tire. In a 5 degree negative camber (or opposite camber), for example if the rider turns the bars for what would be a 40 degree lean angle on a flat surface, he has just put the bike on 45 degree effective lean angle. It's a question of relativeness to a reference point.

 

In riding motorcycles, we don't use gyroscopic instrumentation as we do in aviation to determine bank (lean) angle. Those instruments (attitude indicator) use the gyroscopic principle of rigidity in space. Imagine my surprise to learn in groundschool that the aircraft actually rotates around the instrument which is fixed to the instrument panel!!!

 

When riding cambered turns, it becomes a little bit of an analytical exercise to determine proper lean angle as we human beings are designed to be perpendicular to the force of the Earth's gravity. We like it to point straight down. This is why you can sometimes see a novice motorcycle rider tilting his head opposite the lean angle of the bike, they haven't given their inner ear and eyes sufficient library to become comfortable with the conflicting data of gravity pushing one direction (inner ear sensations) and their eyes seeing a titled plane of motion. Camber adds another level of learning curve. The rider must again reconcile the inner ear and vision for the effective lean angle through the turn.