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Can someone please clarify the WM figure of 1/16" toe-in please?

 

Basically my question is, over what distance should the 1/16" toe-in occur?

For example.............

Is it over the distance across the rim (lip-lip)?

Or maybe, over the overall 25" diameter of the tyre?

 

Funny that I can find numerous threads and videos that explain how to measure it but none are clear about the point I'm asking about.

 

PS

Of course, if it were specified as an angle I wouldn't have to be asking the question.

 

Many thanks

 

Norman

Edited by TRnorm
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Perfect - many thanks

Norman

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Just a point, you do realise that the toe in dimension applies to the tracking of the car and not as an individual wheel ...right ?

 

As in the dimension when measured across the CAR between the front of both wheels needs to be 1/16th less than the dimension measured across the CAR between the rear of both wheels.

If you set the toe in at 1/16 from parallel on each wheel you'll actually set the toe in at 1/8th toe.

 

Mick Richards

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Hi Norman

 

As Mick has pointed out it involves the track width, so it is also important to centre your steering rack before you make adjustments.

 

Just go from lock-to-lock and then to centre. That will be your straight ahead position. Then adjust wheels to parallel, and then, as Mick says, half of a 1/16" on each wheel for correct toe in.

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PS

Of course, if it were specified as an angle I wouldn't have to be asking the question.

 

Many thanks

 

Norman

----------------------------------------------------------------------------------------------------------------------

 

Angle (per wheel) works out to 0.1195° toe in.

 

Tan .1195° = 1/32" divided by 15"

 

.002085 = 0.03125 / 15 (near enough)

 

For info Revingtons recommend a toe in of 0.33° (presumably per wheel, as internet browsing suggest that modern angle spec of toe in is per wheel)

 

Bob.

Edited by Lebro
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Whew guys, this is all a bit OTT for our cars.

 

Simply put our cars would ideally run the front wheels parallel to each other in a dead ahead position.

 

That was quite an ask for the average fitter/mechanic of the day with the equipment an ordinary tyre bay/garage would have.

 

So parallel to a 1/16th of an inch toe-in was the advice. i.e. parallel but err towards toe-in rather than toe-out, thats it!

 

John.

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"Simply put our cars would ideally run the front wheels parallel to each other in a dead ahead position."

 

Sorry John this is wrong, the cars handling is dependant upon it's tracking whether toe out or in, get it the wrong way and the handling changes, didn't I read you were having troubles with yours ?

 

I've written a small article about "Bump Steer" and how to remove it from the TR and also it shows how changing toe in or out changes the handling, it's available to anybody who wants it (so far 160 forum people have requested and running), if you want a copy (with photos) PM me your e mail address.

 

Mick Richards

Edited by Motorsport Mickey
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It was my understanding that toe in is specified to account for compliance in the suspension mounts so as to get near to parallel when the car is rolling.

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It was my understanding that toe in is specified to account for compliance in the suspension mounts so as to get near to parallel when the car is rolling.

Yes.

I set mine parallel as the nylatron/stainless bushes have 'no' compliance. Polybushes must be stiffer than rubber. And old rubber bushes so distorted that the geometry cannot be set right.

Edited by Peter Cobbold
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If you go to a tyre place, it will be 20 minutes of arc toe-in i.e. one-third of a degree. That is measured across the pair of front wheels.

The steering is very odd if set to toe-out since one has to correct constantly as the car darts to left or right!

Ian Cornish

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Hi Mick,

 

sorry but no, on our cars for want of a better term,

 

ordinary cars with ordinary driving, then parallel to 1/16th inch Toe-in is it

 

end of!

 

John.

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Agreed Pete. Personal experience has shown that toe-in stops the tendency for a car to pull to the nearside where the road is cambered but it makes the steering a bit less responsive to directional changes. Toe-out makes it more 'twitchy' but liable to follow all the road irregularities.

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Hi Folks,

it is a bit like Dihedral and Anhedral on aircraft wings.

Dihedral (Toe-in) have the wings pointing upwards slightly and creates a very stable flight path. The aircraft wants to naturally lay flat in the air.

Anhedral (Toe-out) have the wings pointing downwards slightly and creates a very unstable flight path. The aircraft wants to fall out of the sky.

 

Anhedral is very useful for rapid manoeuvrability as per RAF aircraft etc.

Why Russian civil aircraft want to fall out of the sky I do not know.

 

Roger

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