Camber V.S. Straight-Line Speed

[Kronos]

I've heard two different viewpoints on the trade-off between camber and speed.

1) Increased camber angle results in greater straight-line speed because less of the tyre is in contact with the track, and so rolling resistance is less.

2) Increased camber angle results in lower straight-line speed because with a smaller area of the tyre in contact with the ground, greater pressure is exerted on the tyre - resulting in more distortion of the tyre, and more energy being consumed. Hence, less energy is available for overcoming everything else trying to slow the car..

I'd be very glad if anyone could explain why either of these (seemingly valid) theories would outweigh the other.

- Kronos

[strad]

It's number 1..less resistance.

[raymondu999]

Having said that braking distances would be a greater as the front grip when braking won't be as great (when braking in a straight line; not sure about when turning - maybe JET can help out on that)

[strad]

I'm pretty sure that under compression from braking you lose all but very extreme camber.

[bill shoe]

Car going in straight line-- Adding negative camber creates lateral camber thrust (tires push inward toward car centerline). There is no net camber thrust because left and right cancel each other out laterally (assume symmetrical setup).

However, I believe there is a longitudinal price to pay for the lateral camber thrust. Surely the lateral camber thrust is not "free" in terms of longitudinal force. The longitudinal resistance doesn't cancel out, it is still there.

Logically, you could take the negative camber setup and add a bit of toe-out at the front to eliminate the lateral thrust and the associated longitudinal rolling drag. My intuition is that this combination of negative-camber and toe-out has more overall rolling resistance than no-camber and no-toe. Not sure though.

So I am guessing roughly #2. Take this more as logical speculation than hard info.

Strad, what cars/tires or theory leads you to say #1?

[strad]

Strad, what cars/tires or theory leads you to say #1?

Quite simple..The effect of camber could be seen in the extreme on the Red Bulls.
Where they blistered was where most of the contact/weight bearing was..That narrow band presents a lot less resistance than when the tire is standing upright and making full contact across the face of the tire.
Toe in or toe out would just increase the rolling resistance.

[marcush.]

You are putting heat into the tyre differently with more camber ,I think .The car sitting far more only on the inside sidewall and thus will be sprung softer due to this .the working intense working of the sidewall going straight will work the carcass harde and heat the tyre more inside out through carcass ...it will take longer to arrive at leveled out tyre temps.
With less camber the tare surface will be more evenly loaded and so the tyre wíll warm up also from the compound side -

The question is why RedBull is using more camber ? does the RB7 roll more and they have to compensate? or are the other teams simply chicken and stick to pirelli recommendation and not more?

[rock1]

On another point, I think the teams need to be careful with the amount of camber. These tyres are totally different to previous years of late and they do risk the drivers saftey if not knowing the limits that they can run on. The blistering on sunday was not that bad from other times I have seen but still bad enough to be risky.

[marcush.]

the blistering is not good also for performance and it is giving vibrations.

The reason RB went for the camber they chose is performance no question .So do the others leave a chunk on the table and play chicken when real men go out and ignore the blisters?

[bill shoe]

Strad, what cars/tires or theory leads you to say #1?

Quite simple..The effect of camber could be seen in the extreme on the Red Bulls.
Where they blistered was where most of the contact/weight bearing was..That narrow band presents a lot less resistance than when the tire is standing upright and making full contact across the face of the tire.
Toe in or toe out would just increase the rolling resistance.

I don't buy this as a good argument. It is true that the narrow band was carrying more weight in a straight line, but think about what is happening overall.

As a first approximation the contact patch stays the same size regardless of camber (if air pressure and vertical load are constant). Therefore the supported car weight per unit of contact patch area stays the same. The weight and pressure issues don't change.

The tire has some internal damping. This damping combined with the tire deformation is where rolling resistance comes from. The most severe rolling deformation occurs in two places-- the leading and trailing edges of the contact patch. Look there to determine overall rolling resistance.

If you put more air in the tire then the contact patch becomes smaller, but this in itself does not decrease rolling resistance. The resistance decreases because smaller (shorter) contact patches result in less deformation (less angle change) in the leading and trailing edges of the contact patch. The tire comes closer to maintaining a perfect circle through these transitions.

Negative camber makes the contact patch longer on the inside shoulder (more deformation) and shorter on the outside shoulder (less deformation). Which wins? Is the overall resistance higher or lower?

It gets complicated here and you would probably have to include temp effects. However, my intuition is that negative camber surely does not reduce rolling resistance in a straight line. If it did then highly efficient vehicles such as the Toyota Prius would use a lot of negative camber.

[raymondu999]

Someone page for JET please

[marcush.]

I´d think with more camber and as you load only the inside shoulder the tyre is behaving softer in spring characteristic.so it is going to squash more doing more deformation work -leading to more resistance? I think this is a moving target as the compound rising temperature will first increase grip but when the thing is already starting to blister

[RacingManiac]

Strad, what cars/tires or theory leads you to say #1?

Quite simple..The effect of camber could be seen in the extreme on the Red Bulls.
Where they blistered was where most of the contact/weight bearing was..That narrow band presents a lot less resistance than when the tire is standing upright and making full contact across the face of the tire.
Toe in or toe out would just increase the rolling resistance.

I don't buy this as a good argument. It is true that the narrow band was carrying more weight in a straight line, but think about what is happening overall.

As a first approximation the contact patch stays the same size regardless of camber (if air pressure and vertical load are constant). Therefore the supported car weight per unit of contact patch area stays the same. The weight and pressure issues don't change.

The tire has some internal damping. This damping combined with the tire deformation is where rolling resistance comes from. The most severe rolling deformation occurs in two places-- the leading and trailing edges of the contact patch. Look there to determine overall rolling resistance.

If you put more air in the tire then the contact patch becomes smaller, but this in itself does not decrease rolling resistance. The resistance decreases because smaller (shorter) contact patches result in less deformation (less angle change) in the leading and trailing edges of the contact patch. The tire comes closer to maintaining a perfect circle through these transitions.

Negative camber makes the contact patch longer on the inside shoulder (more deformation) and shorter on the outside shoulder (less deformation). Which wins? Is the overall resistance higher or lower?

It gets complicated here and you would probably have to include temp effects. However, my intuition is that negative camber surely does not reduce rolling resistance in a straight line. If it did then highly efficient vehicles such as the Toyota Prius would use a lot of negative camber.

I'd buy this, the long and narrow contact patch I'd image may "drag" itself across the surface more in a straight line, which probably causes more resistance...

[strad]

[bill shoe]

http://en.wikipedia.org/wiki/Toe_(automotive)

Interaction with Camber

When a wheel is set up to have some camber angle, the interaction between the tire and road surface causes the wheel to tend to want to roll in a curve, as if it were part of a conical surface (camber thrust). This tendency to turn increases the rolling resistance as well as increasing tire wear. A small degree of toe (toe-out for negative camber, toe-in for positive camber) will cancel this turning tendency, reducing wear and rolling resistance. On some competition vehicles such as go-karts, especially where power is extremely limited and is highly regulated by the rules of the sport, these effects can become very significant in terms of competitiveness and performance.

Unfortunately there is no citation for this info.

No, I didn't write it even though it is similar to my initial post in this thread. I didn't see it until now. It is logical, but in the absence of a reference or any knowledge of who wrote it I would not consider it a definitive confirmation.