Car cornering: side force between external and internal tire

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Discussion Overview

The discussion revolves around the side forces experienced by the tires of a vehicle during steady state cornering, specifically comparing the external and internal tires on the same axle. Participants explore the effects of weight transfer, tire load, and slip angles on the forces acting on each tire.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants propose that the external tire experiences higher side forces due to greater normal load from weight transfer during cornering.
  • Others argue that while the external tire may have a higher load in symmetrical cars, it is possible for an asymmetrical car to have the internal tire carry a higher load, leading to potentially higher cornering forces.
  • A participant mentions that the relationship between vertical load and side load is complex, influenced by factors such as slip angle and toe angle adjustments.
  • One participant explains that in a left-hand turn, lateral load transfer results in the right tires generally experiencing more load, but this can vary based on the vehicle's engine location and configuration.
  • There is a question raised about the implications of toe angles on slip angles and tire wear, particularly regarding the effects of toe-in and toe-out during cornering.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between tire load and side force, with no consensus reached on which tire experiences higher side forces under varying conditions.

Contextual Notes

Participants note that the discussion is influenced by assumptions about vehicle symmetry, weight distribution, and the effects of suspension geometry on tire behavior, which remain unresolved.

serbring
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Hi all,

During steady state cornering which tire of the same axle experiences the higher side force? I believe the external one for higher normal load due to the weight lateral transfer. Is it true?
 
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The wheel effectively traveling the furthest distance with being exerted to the most pressure, so yes, the outter (external) tyre.
 
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thanks a lot
 
22ashc said:
The wheel effectively traveling the furthest distance with being exerted to the most pressure, so yes, the outter (external) tyre.

I don't think that necessarily follows. The one experiencing the higher force should be the one with the higher load. Yes, on a symmetrical car, this will be the outer one due to weight transfer in the corner, but you could conceivably make a car with one side much heavier than the other, such that even when the heavy side was on the inside of a corner, it would still have a higher tire load than the outside. Then I would expect the higher cornering load on the inside tire.
 
cjl said:
I don't think that necessarily follows. The one experiencing the higher force should be the one with the higher load. Yes, on a symmetrical car, this will be the outer one due to weight transfer in the corner ...
That would translate into a higher vertical load, but the original question is about side loads. One of the factors affecting side loads is "slip" angle, how much "inwards" is the orientation of the tire versus it's actual path. If there's "toe in", then the inner tire has less slip angle, if there's "toe out" (an effect of ackerman steering on street cars for tire wear, not for cornering performance), then the inner tire would have more slip angle (when not cornering near the limits of traction). I'm not sure about the combined effects of vertical load versus side load versus slip angle.
 
In a left hand steady state turn you are dealing with lateral load transfer. This assumes the weight coming from the rear of the car and the cross weight has already shifted and been countered by the spring/ shock ( damper) and is not oscillating. Now in a left hand steady state turn the right front tire and right rear tire will have more load than the other two. Typically the right front is the most loaded but this depends upon where the engine is located..frt wheel drive Ft. engine. RWD Ft. engine RWD rear engine or ft. wheel drive rear engine.
You are correct in that vertical load on a tire increases the tires ability to accept more load ..to a point..for more detail see race car suspension class posts on this forum
 
rcgldr said:
If there's "toe in", then the inner tire has less slip angle, if there's "toe out" (an effect of ackerman steering on street cars for tire wear, not for cornering performance), then the inner tire would have more slip angle (when not cornering near the limits of traction).
1.Why would more slip angle during turns(toe-out) imply less tire wear?The rubber flexes more than it would in toe-in right?Wouldn't this imply more tire wear in toe-out? (in relation to the inner wheel).
 

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