Talk:Lift-off oversteer

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[edit] Requested rename

"Lift-off oversteer" gets around 10k google hits, while "drop throttle oversteer" and "trailing-throttle oversteer" get around 1k google hits each. I'm not an expert, but I've heard "lift-off oversteer" more often as well. Might it make sense to rename the article to "lift-off oversteer"? --Interiot 04:52, 29 March 2006 (UTC)

Ahh, it can be refered to as "lift-throttle oversteer" as well, which also gets 1k hits. Anyway, I've moved it to "lift-off oversteer". --Interiot 23:28, 17 April 2006 (UTC)

Snap-oversteer gets 20k google hits. I've setup a redirect, but it's something that we might want to think about in the future. Morwan 03:32, 2 December 2006 (UTC)

Isn't that like the new "drifting" the "cars" are now into, especially the rear engine foreign type as mentioned in the definition? Ttwould 20:39, 3 August 2006 (UTC)

[edit] Physics

I'm not a physicist or car expert, but I believe the operative principle is not the decrease of contact patch size, but the reduce of normal force. Classical friction is based on coefficient between surfaces and force between them. The force between them is based on the normal force, which counteracts the weight of the car. As the car's weight transfers forward, less downward force is applied to the rear wheels, so the road pushes back with less normal force, so there is less force between the tire and road, so there is less friction. The size of the contact patch is unimportant - the same force of friction applies.

However, classical physics is often oversimplified. I'm sure there are much more important issues, such as deformation of the tire and the characteristics of the rubber.

Anyone who knows the physics of cars, please contribute! jauricchio 17:26, 1 September 2006 (UTC)

You are correct, sort of. If you look into the reason as to why the static friction available increases with increased force perpendicular to the planes, it is because the contact patch 'grows'. The idea is that with, say 100 kg, 20% of the atoms in a tire (for instance) will be touching the ground. 200 kg, and the next 20% of the atoms touch. The increased force increases the contact patch (even if you cannot see it with the naked eye) and this increases the static friction. An interesting effect this gives rise to, is that, if you go over a certain amount of force, you will stop gaining traction. In our example 500kgs of force will have 100% of the atoms touching, so 600kg will not add any traction past 500.

Off course, I don't remember where I learned that, and there is a very good chance it wasn't from university or any other educational institute. So its not bible. Nereth 11:36, 16 June 2007 (UTC)

As another physics based question, from the same guy that posted the above answer:

I don't understand this: 'This decrease in vertical load causes a decrease in the lateral force generated by the rear axle, so the axle starts to accelerate towards the outside of the turn.'

I can understand that the decrease in vertical load will decrease traction available, but whats that about lateral force? Decreasing the vertical load by coming off the throttle cant, as far as I know, cause the tire to break out of static friction, since the decrease in force transmitted to the tire to move the car FORWARD would be more than enough to counteract any loss of traction from weight transfer away from rear tires. Am I thinking about this wrong? Someone help me out :/ Nereth 11:39, 16 June 2007 (UTC)

The article is correct and sensible. Think about how tires work. see Tire load sensitivity. You seem fixated on static friction. That is not very helpful in this context. Greglocock 22:46, 16 June 2007 (UTC)

[edit] OR tag

Please discuss the OR tag here, otherwise I will remove it in two weeks. Greg Locock (talk) 21:58, 2 January 2008 (UTC)

The section lacks references to the origin of the test data and the analysis. If the origin is the editor, it is Original Research. --rxnd ( t | € | c ) 07:50, 3 January 2008 (UTC)

Yup, I made a digitalised image of a model of the phenomenon being discussed. OR? How would removing it improve the article? No unusual conclusions are being drawn from the graphs. Greg Locock (talk) 09:30, 3 January 2008 (UTC)

Per definition it is then OR. I agree in that the section and the image does add to the article. Nevertheless, Wikipedia cannot be a primary source. You are citing yourself. --rxnd ( t | € | c ) 11:37, 3 January 2008 (UTC)

There is no citation involved. This is an illustration for explanatory purposes, not research. Following your logic no photos (digital images) taken by an article's editor are allowed in an article? see Geelong and its talk page where we take digital images of the subject and include them in the article. Greg Locock (talk) 11:48, 3 January 2008 (UTC)

The graphs are generated based on an experiement, the photos of Geelong are not. Not citing yourself although it is your original material does not make it less original. Nevertheless, seeing that the image and analysis is of use, I will not push this issue too far. If you strongly feel that this is not a primary source and that there is no way to replace it with a secondary source, I see no problem with removing the OR tag. --rxnd ( t | € | c ) 13:00, 3 January 2008 (UTC)

I've checked 2 books about vehicle dynamics. Neither have much discussion of lift off oversteer, although Milliken does mention it in the tuning guide p397. I'm glad you don't want to push it as there doesn't seem much point. As to experiments... philosophically speaking would a video of a car undergoing this test be OK? I think so. Would the video be OK if it had a g meter reading superimposed? yes? So why does a computer model of the same thing count as OR? Greg Locock (talk) 20:31, 3 January 2008 (UTC)