Toe out for turn in

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Jersey Tom
166
Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Toe out for turn in

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Within a system, sure.. if you control force then slip angle is an output which will be contingent on the full set of tire states which include load.

However, the point still is that the definition "is what it is" and slip angle and load are two independent quantities used to define a state.

In any event, I thought we had pretty clearly answered the question some time ago. I'll be honest, I haven't followed what's really been said over the past several posts.

And yes, strad. Difference between orientation (how you point an object) vs the direction of travel (where it goes). However, sideslip doesn't have a preference for what medium you're working through.. be it driving across the ground or flying through the air.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

GSpeedR
26
Joined: 14 Jul 2011, 20:14

Re: Toe out for turn in

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Jersey Tom wrote:Within a system, sure.. if you control force then slip angle is an output which will be contingent on the full set of tire states which include load.
My point is all systems control force, whether a tire tester or a full vehicle.
However, the point still is that the definition "is what it is" and slip angle and load are two independent quantities used to define a state.
I'm not disagreeing with you, I'm pointing out to the general audience that it may be advantageous to look at tires with a different perspective than what you'll find in RCVD or Pacejka. An engineer must understand the tire model before they can do that.

EAKMotorsports
0
Joined: 31 Jan 2007, 07:17

Re: Toe out for turn in

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How about the F1 TOE.
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Jersey Tom
166
Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Toe out for turn in

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EAKMotorsports wrote:How about the F1 TOE.
Yes.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

EAKMotorsports
0
Joined: 31 Jan 2007, 07:17

Re: Toe out for turn in

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They uses negative or positive on the front and the rear ?
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raymondu999
54
Joined: 04 Feb 2010, 07:31

Re: Toe out for turn in

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EAKMotorsports wrote:They uses negative or positive on the front and the rear ?
Negative. A bit more negative in the front; a bit less in the rear.
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olefud
79
Joined: 13 Mar 2011, 00:10
Location: Boulder, Colorado USA

Re: Toe out for turn in

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I'm wondering what the definition of "slip angle" might be. Often the state of a tire running at a slip angle is distinguished from one sliding or washing.
The former involves the elastomeric deformation of the tire but little actual relative movement between the tire and the track at the contact patch. The latter involves the loss of static friction and transition to lower grip sliding friction. I can't defend this definition, but others seem to subscibe to it.

Or is "slip angle" just difference between the direction the wheel points and the direction it travels?

Jersey Tom
166
Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Toe out for turn in

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olefud wrote:Or is "slip angle" just difference between the direction the wheel points and the direction it travels?
That is literally all it is. Nothing to do with linear range versus sliding, tire deflection, or anything. Purely a comparison of rim orientation to direction of travel.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

Rustem 1988
0
Joined: 05 Sep 2017, 11:38

Re: Toe out for turn in

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In the middle of corner, the load on the inner and outer wheel can be no stable?

bigpat
19
Joined: 29 Mar 2012, 01:50

Re: Toe out for turn in

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Theory is great, but reality demonstrates that tie out helps with turn in.
In F3000 spec cars we ran 3-5 mm toe out on the front. And 6-10mm toe in at the rear.

It is something is equally applicable to go karts as well...
Toe in is dynamically stable as it self centres, the opposite being true of toe out. It is more effective in cases where mechanical grip is not 'blanketed' by aero grip.
It has and still is a quick and easy method to help dial some more 'point' into a car, as well as help get some tyre temperature through scrubbing. Obviously it not something you can maximise at high speed tracks where friction on the straights is a concern.

johnny comelately
110
Joined: 10 Apr 2015, 00:55
Location: Australia

Re: Toe out for turn in

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Might be important to clarify when talking rear or fronts.
Something that maybe of interest is that in the cave man days , 1976/77, Indy cars were using toe-in on the rear which tightened the whole behaviour of the car up. (Vern Schuppan) which was a revelation to F5000 setups, here in Australia at the time.
so when I saw the title of this post , i immediately thought of the rears and how maybe that would work for turn in, a la rear wheel steering effect. (and to hell with the better tighter feel :) )

Tommy Cookers
617
Joined: 17 Feb 2012, 16:55

Re: Toe out for turn in

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didn't toe adjustability came (into single-seaters) by design-evolution accident c. 1960 ? (and toe steer/or not by design)
Chapman and Broadley etc weren't slow on the uptake

the accident of moving suspension linkages to structurally advantageous positions enabled by using spherical bearings ?

johnny comelately
110
Joined: 10 Apr 2015, 00:55
Location: Australia

Re: Toe out for turn in

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Tommy Cookers wrote:
17 Feb 2018, 15:22
didn't toe adjustability came (into single-seaters) by design-evolution accident c. 1960 ? (and toe steer/or not by design)
Chapman and Broadley etc weren't slow on the uptake

the accident was moving suspension linkages to structurally advantageous positions enabled by the introduction of spherical bearings ?
Tommy, I take it you are talking about rears?

Tommy Cookers
617
Joined: 17 Feb 2012, 16:55

Re: Toe out for turn in

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well I was hedging my bets (of course anything could set and control the front alignment by adjustment of the steering linkage)

the rear suspension of the Lotus 18 (1960) had a lower reversed wishbone adjustable to set and control the toe

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Zynerji
111
Joined: 27 Jan 2016, 16:14

Re: Toe out for turn in

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I know several SIM racing Aliens that live by 3 degrees of toe IN on the front, and 1.5 degree toe OUT on the rear on F1 machinery.

Might work fine in a sim, but not on a real track.

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