Toe-In/Out - what's the real handling influence - your experiences ?

[chris7676]

Was wondering what the practical influence on car's handling and feel toe settings have, especially in a mind-engined car. Apparently in theory toe-in increases stability while to-out encourages turning. However some suggested that some FRONT toe-in actually improves turn-in and improves front grip.

 

Based on my (limited) MR2 MK1 experience, I used to have a big front toe-out (over 4mm) before the alignment, then 1.5mm toe-in after, and now it's parallel. Interestingly, the toe-out didnt make the car unstable but made it felt willing in turns. Subjetively toe-in felt not so turn-happy though the initial bite seemed better.

 

They may have been other factors, yet camber & castor influence seems easier to grasp, while toe seems more subtle though apparently very important.

 

So what's the real influence on handling?

Any practical experiences and feedback?

[Tony]

Huge topic mate with many factors to consider..

 

Toe in essence has many duties. Domestically the static position is a calculation the dynamic toe will be 0, the actual position is dependant of the type of drive the car has.

 

For the track we need to factor areas like "toe gain" on/off the bump and lateral gain as a compressive force. The cars dynamic index and steering rack position rate high in this calculation.

 

The MR2 being so light on the front is less receptive to low toe corrections, normally aggressive amounts are used but this is an extremely delicate balance since independently each front tyre will steer if the toe positions are to aggressive, in particular under braking and during weight transfer.

[Sam@TDi]

Tony's right this is a huge topic, especially if you consider dynamic toe effects as the suspension moves or is loaded with forces.

 

But to put it simply...

 

Front axle:

 

Positive toe (toe-in) = Livens the axle up

Negative toe (toe-out) = Calms the axle down

 

The exact opposite is true at the rear axle... never toe-out the rear axle!... unless your building a grasstrack car

[jammy]

numpty alert

 

 

 

so toe in will make a sharper turn then?and give it a stable and direct drive and toe out will give it a lazy feal on the turn into a corner????????????and dosnt hold a continuos line through the bend and tend to wonder more in a straight line

 

the toe out 1 was a prob i got with my golf! and where the camber was so aggressive due to 80 mm drop it almost felt like it had no turn what so ever unless you literally through it into the bend !

 

 

still cant find them pic's of my golf so want to show you my little experiance whilst on way to the shop's

[Tony]

Jammy the problem explaining toe is that it's so dynamic.

 

When people talk about toe in or out it's perceived as static image and assumed to retain it's position regardless of any exterior forces.

 

For the domestic car we can assume some reasonable kinematics since the manufactureur should have invested some time into the chassis positions.

 

A modified car needs additional research since the chassis fluid dynamics becomes totally theoretical so a need to develop kinematic circumstances becomes critical, ever more so it the car is intended for the track.

[jammy]

so does that mean on my golf then with the toe whilst in motion then would be greater then if were static

[Tony]

so does that mean on my golf then with the toe whilst in motion then would be greater then if were static

 

Static we would pull the car down to see the dynamic toe gains.

 

This is done central and diagonal to optimise the collective data.

 

Once done it is possible to assume a static position for the modified car, offering a better overall dynamic toe position.

 

Problem is we also need to consider the camber/castor/kpi since they are also involved in the toe dance....

[Sam@TDi]

Welcome to geometry

[jon]

My experience of front toe is thus:

 

Toe out: stable front, picks up understeer fairly easily

Toe in: sharper turn in, more solid, bit more lively

[Tony]

My experience of front toe is thus:

 

Toe out: stable front, picks up understeer fairly easily

Toe in: sharper turn in, more solid, bit more lively

 

There are so many parameters involved here i feel the topic is to difficult to explain as a general overview.

 

Generally toe out makes the car feel nervous, involving high levels of steering corrections.

 

Toe in tends to make the steering feel lazy and aggravating to some drivers.

 

Domestically all cars regardless of drive acquire a 0 toe dynamically.

 

On the track......... Each car is unique and falls into a matrix of calculations as personal as a fingerprint.

[jon]

You're right Tony, I should have added "My LIMITED AND ANECDOTAL experience of front toe is thus".

 

The MR2 is a strange girl, as is my setup and driving style!

[Tony]

You're right Tony, I should have added "My LIMITED AND ANECDOTAL experience of front toe is thus".

 

The MR2 is a strange girl, as is my setup and driving style!

 

"DRIVING STYLE"....... After the test drive with you i'm having therapy.... Apparently i keep mumbling "brake...brake...brake" under my breath

[jammy]

so does that mean on my golf then with the toe whilst in motion then would be greater then if were static

 

Static we would pull the car down to see the dynamic toe gains.

 

This is done central and diagonal to optimise the collective data.

 

Once done it is possible to assume a static position for the modified car, offering a better overall dynamic toe position.

 

Problem is we also need to consider the camber/castor/kpi since they are also involved in the toe dance....

 

think im understand well abit anyhoo

 

 

 

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