# Tire Physics and slip angle

• Automotive

## Main Question or Discussion Point

Hello everyone,

Does anyone know what the slip angle is in relation to rubber tires? What is its effect? Is it a positive or negative effect?

My basic understanding is that when a tire is cornering, the tire does not point directly along the curved direction of motion but is slightly twisted, since it is made of rubber, and points slightly towards the outside of the curve...

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sophiecentaur
Gold Member
Have you Googled "Tyre Slip Angle" yet".

FactChecker
Gold Member
Hello everyone,

Does anyone know what the slip angle is in relation to rubber tires? What is its effect? Is it a positive or negative effect?

My basic understanding is that when a tire is cornering, the tire does not point directly along the curved direction of motion but is slightly twisted, since it is made of rubber, and points slightly towards the outside of the curve...
The tire points inward. The tread distorts as the wheel rolls. The tire must point further in the desired turn direction than the vehicle will actually turn.

Ranger Mike
Gold Member
Does anyone know what the slip angle is in relation to rubber tires?
yes

What is its effect?
could be good until it goes to bad

Is it a positive or negative effect?
positive until it goes to negative

My basic understanding is that when a tire is cornering, the tire does not point directly along the curved direction of motion but is slightly twisted, since it is made of rubber, and points slightly towards the outside of the curve...

on a motorcycle? which tire?
on a race car are you talking about the right front in a left turn corner or the left front tire in a left turn?
Or are you talking about the rear tires?

i suggest you read race car suspension class ...above...see page 4 post #62
page 12 post # 228
page 24 post # 470 lumpy and the down force
page 41 post # 811 centrifugal vs centripital

FactChecker
Gold Member
The slip angle is the difference between the direction that a tire is pointing and the direction that it is moving. My experience with it was in simulations that only had to be believable, not necessarily accurate. We modeled it as a lateral (versus tire point direction) force that was a linear function of the slip angle. When the tire points more to the left, the force is to the left.
I assume that a real analysis of turning force would require detailed understanding of the tread design and pattern. It seems that a tire company could more easily set up experimental fixtures than rely on analysis, but I have no authoritative knowledge of that.

sophiecentaur