# Tire slip angle diagram, wet vs. dry

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### #1 giskard

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Posted 19 June 2012 - 03:29

Hi all,

Does someone have a link to a tire slip angle diagram, so I can see how it changes from dry to wet?
I want to understand why tires behave the way they do in the wet (e.g., cornering force past the peak at very high slip angles, is a larger % down from the peak, in the wet vs. dry, or the dropoff is more abrupt).

Cheers.

### #2 giskard

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Posted 20 June 2012 - 03:18

Thanks.
I was curious about street tires.

Basically I want to understand why a car behaves like this in the wet:

The diagram in your first post doesn't make sense wrt what I think it should be.
Upper left hand diagram in 2nd post does:
- wet grip peaks early then drops

Have you seen any more diagrams? The tire book by Haney is good but doesn't show any comparison of wet vs dry for a hi perf street tire.

The paper you linked was pretty interesting BTW.

### #3 Greg Locock

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Posted 20 June 2012 - 04:51

The diagram in your first post doesn't make sense wrt what I think it should be.
Upper left hand diagram in 2nd post does:
- wet grip peaks early then drops

And there I was thinking how well they agreed

### #4 giskard

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Posted 20 June 2012 - 14:48

And there I was thinking how well they agreed

So do you agree or disagree that they agree?

### #5 giskard

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Posted 21 June 2012 - 15:58

But it does so too, in the first diagram - No?
The main difference is, IMO, that the second diagram, does not show the slip angle range past peak value for the dry road.

Anyways, it's a complex matter, and I'm not the expert for it.
There are many factors coming into play here, and all of them have a effect on the final outcome.
Not sure, how deep you want/need to dive into the subject, but you may find some "food for thought"

Here CAUTION !!! it's an 850 page pdf file, so may take a while to load

and

here

good luck

Thanks. I looked at all the diagrams and didn't see a slip angle diagram showing wet vs dry.

### #6 Greg Locock

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Posted 21 June 2012 - 23:04

The Milliken Moment Method plot is a nice way of looking at a tire. I don't remember seeing an MMM for a wet tire. Thanks for all the refs, there's a lot in there. I like the data one, as you can imagine the files off a modern tire rig look much like that.