Miata Mailing List: September 1998, Message #78

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Sonja62786@aol.com wrote:

>Toe-out facilitates turn in...... downside: twitchiness
>
>Toe-in promotes good straight-line tracking.....downside...comparatively
>slower response to change of direction.
>
>I definitely want some toe-in for street and track, but could use a touch
>of toe-out for autocross
>

Will was talking about toe setting on the front wheels. Front toe works
the opposite way than rear toe: toe-in = good turn in but twitch. It seems
like there's a general misunderstanding of the effect of front toe-in.  To
understand that front toe works the opposite way as the rear toe does,
think about a car turns in the front wheel steering direction but turns
against the rear wheel steering direction. 

Normally, RWD cars needs a tiny bit of toe-in in the front while FWD cars
needs some toe-out in the front. The reason is that when a RWD car travels
straight on the highway, the friction on the front wheels forces the right
wheel to turn right and left wheel to turn left; thus generating a toe out
condition. The rear wheels encounter the opposite because the driving
force on the wheels tries to make the right wheel turn left and left wheel
turn right.

By the same token, the driving force on the front wheels of a FWD car
forces the right front wheel to turn left and left front wheel to turn
right, generating a toe-in condition. Thus, a front toe-out alignment
setting is need for FWD car while a RWD car needs front toe-in. 

We must admit that the miata has much better steering response than many
other RWD cars. That's why people run toe-out in the front to tune down
the over-reactive steering. If you don't believe me, try lengthen the
tie-rods on your miata to get more toe-in (if currently toe-out) and try
twitching the steering wheel repeatedly left and right (about an inch
either way) and you should be able to feel the car turning more
responsively to the tiny steering input. 


--
Chris Chu and Shirotora
'90 Crystal White
http://infomatch.com/~cchu/
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