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Gtir Motorsport club » Tech room » suspension set up & info » Write up regarding toe in - toe out settings for track & fast road

Write up regarding toe in - toe out settings for track & fast road

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GTI-R US

GTI-R US
Management
Management
Ok guys / gals here i have put together what i think is a fairly easy to understand write up on basics of car  set up mainly for track use but can also be adopted on road, hopefully may be of help to some of you.



If you love racing, doing trackdays etc &  are looking to get the absolute maximum out of your car on a track/race day, making sure your front wheels are pointing in the right direction would seem like an obvious thing to do.
But the right direction doesn’t necessarily mean the same direction so in this post you will see why you might not want to have your front wheels facing forward & parallel.


In neutral conditions cars are more stable in a straight line when the wheels are pointing in the same direction. It’s not only good for stability, it also minimises tyre wear and maximises the conversion of sheer power into forward motion giving you maximum ground coverage with minimum effort from the engine and transmission. Neutral conditions however are rare.
Cars are constantly accelerating, decelerating, cornering whilst going up and down hills and encountering all types of obstacles and varying surface types. But that’s not really a big deal in an ordinary road car.
So unless you’re one of those people that have appeared on “Police, Camera Action” it’s highly unlikely youll be taking a road car to the limit of its capabilities. But if however your a track day nutter or going circuit racing you just might reach those limits… thats when you need to adapt certain settings to suspension geometry so il start with the easiest one being do i go for toe in or toe out???
Toe in, as you’ll see below is when both of the front wheels are pointing inwards whilst Toe out is – the complete opposite of course.

toe in

So why would you choose to opt for either of these setups if they’re going to increase tyre wear and reduce the effectiveness of power delivery? Well the answer lies in the cars directional stability.

By going for a ‘toe in’ setup under normal perfectly flat conditions the wheels would point inwards and the car would drive forwards in line a little less efficiently than normal, more effort required from engine / transmission to get power down.
However with the state of the roads in uk ''potholes, bumps, irregularities'' its likely to pull the front wheels rearward on the steering axis which in effect straightens their line.
What this means, is that unless your driving on a perfectly flat and perfectly smooth surface having an angle of ‘toe in’ will ensure your car better absorbs irregularities in the track / road surface, so in a straight line at high speed it gives much more stability.

Toe out

A toe out setting to the contrary will initiate & accentuate a turn when there are indents in the road. This can however make it very unstable and twitchy in straight lines so is not really recommended for road cars, but it does make it extra sharp when turning into corners which is great for serious track dayers on high speed cornering circuits or ovals.
So adding a small amount of toe out is certainly something to consider if you’re racing a fwd or 4wd car (gtir is a very good example with its high levels of understeer) on circuit

You do however have 4 wheels on a car so you might want to consider your toe settings for the rear of the car but you need to be careful as this is far more sensitive with steering input.
A toe out setup can produce a lot of instability on the straights so its a common practice to counter this with a toe in set up on the rear to help keep the car under control.
So in a nutshell for a Gtir and many other cars if being used on track a toe out front and toe in rear setting is a good start to help you stay on the tarmac and out of the kitty litter or worse still an armco barrier lol

So in summary

Front toe out will introduce a bit of oversteer...... looser rear end
Front toe in will induce the opposite meaning understeer......looser front end
Steering response will be improved with front toe out
Straight-line stability will be improved with front toe in
Rear toe in should be coupled mostly with front toe out
Rear toe out front toe in is also used on a variety of vehicles....just remember (opposites attract) and you wont go far wrong

There is no optimum setting as such as steering geometry is determined by whatever car you drive be it rwd, fwd or 4wd, the curcuit your on & weather conditions your driving i.
Ultimately the driver of the car is the biggest varying factor as everyone has a different driving style with some being aggressive with steering input & controls whilst others are far smoother with car control which ultimately will determine the setup you as a driver go for.

Hopefully this post will give you some basics & fundamentals of what your car is doing and why its doing it, but
there is far more involved as other factors castor, steering axis, bump steer, king pin inclination, tyre choice and so forth play a major part in obtaining the optimum handling setting

This link to how it all works if you want to learn more with what your car is doing on track or road regarding suspension settings i find is fairly easy to understand as some write ups are very complex and involved which therefore makes them difficult to understand unless your a guru with mathematical geometry such as myself  Laughing

http://www.motor.org.uk/documentlibrary/Sep%2009/TT%20_%20Sept%2009.pdf

Happy reading guys  Wink


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shroom

shroom
Very good rightup Bob I havent really ever looked into suspension setup in detail and have always just had them setup to run straight so will be taking aome of your advice on board!

nomad

nomad
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Admin
Rep given .... just about got my head round it cheers


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gtir_woody

gtir_woody
moderator
moderator
Nice write-up, very well written and explained mate. Suspension set-ups can be a complex beast.

Ali_legend


Wow this was very helpful

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