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 Post Posted: Thu Mar 05, 2015 1:31 pm 
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Joined: Tue Nov 27, 2012 11:59 am
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Location: Sunshine Coast, Qld
Been meaning to both try a few different alignments for a while and then document them here - here goes.

Firstly a quick summary of what you are adjusting and how you might measure it.

There is an app (or 20) for wheel alignment and the one I have works quite well.

Try googling iAlign.

For those who aren't too sure whats what in the front end then have a read of this - http://www.ozebiz.com.au/racetech/theory/align.html

Its a pretty techy version of a possible description so heres the shortened version.

Camber - Negative camber means the top of the front tyres is closer to the longitudinal centerline of the vehicle than the bottom of the tyres. Positive is the other way round (the tyres lean out like an old school racecar). We measure this in degrees.

Caster - Much like the rake on the front of a motorbike. Positive caster means the upper ball joint is behind (more aft) the lower ball joint. Measured in degrees

Toe - I think everyone gets that the toe in or toe out is all that most Bob James (insert generic tyre fitting dodgy wheel alignment companies name here...) tyre shops are aligning and they might not be even doing that. Toe is a measure of whether the tyres are point slightly inward or slightly outward (toe in and toe out respectively). Measured a number of ways.

See diagram below.

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On the Tri Pod 1 we can adjust all three key areas mentioned above. The diagram above shows a number of other aspects of front end geometry. Ignore them as I have 'locked' in those settings. They are not generally adjustable on anything other than a formula car anyway.

Starting at the start you will want the car sitting on a level surface. You will want a phone and phone app or a digital level. A string line and an assistant would be handy too.

In fact if we were to start at the very start you would want to align your rear wheel first.

The chain adjuster marks may or not mean much anymore subject to just how smack on your swingarm mounting in the chassis is. Stringline the sides of the rear tyre forward under the car and mark up the position of both sides at the front of the vehicle (on the floor) and divide the two marks and mark it on the floor to obtain the centre of where the rear tyre is pointing. Measure to a fixed point at the front of the chassis each side and see how centred it is or isn't. Adjust the chain adjusters slightly and re stringline. Obviously we want the wheel pointing dead ahead relative to the chassis. You will end up with a calibration offset number of maybe a quarter of a chain adjuster mark forward on the right versus the left which will have your wheel pointing in the right direction. You can apply this difference when ever you are adjusting the chain to maintain correct rear wheel alignment.

Back in a minute with a diagram then we''ll get on to aligning the front.

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 Post Posted: Thu Mar 05, 2015 3:59 pm 
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Location: Sunshine Coast, Qld
Attachment:
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I hope this makes it a little easier to grasp.

Lets move onto the front end now.

We need to adjust camber and caster first as they will affect the toe out fairly dramatically if wrong and then we change them after a toe adjustment.

Caster is set by the washer packers on the inner upper wishbone mounts. I suggest starting with max caster which on Gen 1 chassis's is 8 or so degrees and on Gen 2 chassis closer to 10 or 11 degrees.

Max probably isn't required on a gen2 but as they aren't out yet we won't concern ourselves with it.

Measure the caster by using the iAlign app or similar or a straight edge and a digital level (lining up the top and bottom ball joint axis's keeping the level vertical in the side to side across the car vertical plane and keeping the wheels pointing straight ahead)). You should have around 8 degrees each side. If its more than a degree different from side to side I would be trying to reduce the high side by packing it forward 1 washer and re measure. Something like 7.8 degrees one side and 8.3 the other is fine, particularly considering our dodgy measuring method.

Now measure the Camber (with the wheels straight ahead) by wacking the level up against the side of the wheel in a vertical plane. No fancy equipment required really just a decent spirit level to make sure the wheel is straight up and down as we want zero camber. To adjust camber you need to knock the top ball joint out of the upright and screw it out of the threaded boss in the upper wishbone for a more positive camber and in a few threads for more negative camber. One thread is approx .3 of a degree if you are using some kind of digital read out and know how much you need.

Once the camber is right lets tweak the toe for about .5 of a degree of toe out.
There are a heap of ways to measure this. Back soon with a couple of methods.

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 Post Posted: Sun Mar 08, 2015 4:01 pm 
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Joined: Tue Nov 27, 2012 11:59 am
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Location: Sunshine Coast, Qld
Back again...

If you run a stringline (or use a laser level of some kind) ahead of the car to a point say 2.5metres in front of the leading edge of (at the widest point) the tyre onto the floor and mark it. Do another at the 5 metre mark. Do this on both wheels giving you a four marks on the floor with pairs of marks approx the width of the car apart.

(An assistant holds the string against the rear widest part of the tyres sidewall about the midpoint (about 300mm off the ground) and instructs you, who is holding the other end of the string on the ground 2.5 and 5metres away to move it left or right so it just touches the forward edge of the tyres sidewall giving you a fairly exact position as to where the tyre is pointing.

Obviously you want the wheels pointing straight ahead while doing this. The fact that you have already adjusted the camber to our preferred position of 0 degrees means the fact that there is a bit of an angle on the stringline across the face of the tyre doesn't matter.

Measuring the distance between the pairs of marks will give us our toe in or out angle for example...

A 20mm difference ie. the closest pair (2.5metre ones) measure say 1810mm apart and the 5 metre ones measure 1830mm we could assume that the front of the tyres (where we measure the 2.5m and 5m distance from) are 1790mm apart.

Trig calculations will tell us that 40/5000 tan-1 will = .46 degrees

A bit of table might be handy -

Difference between 2.5 and 5 metre marks means the following degrees -

5 mm - .11 degrees
10 mm - .23 degrees
15 mm - .34 degrees
20 mm - .46 degrees
25 mm - .57 degrees
30 mm - .69 degrees
35 mm - .80 degrees
40 mm - .92 degrees

I hope this is some help. I think its reasonably accurate. Works for me either way.

If your alignment needs a mild tweak it might be a good time to maybe adjust for your steering wheel's central position if it's a bit off. ie. Adjust one wheel out a bit further than the other like say a quarter turn on one tie rod and a half turn on the other. If when you hold you wheel centrally while driving the car and it heads left you obviously need to toe out the right wheel more than the left and visa versa.

Have fun, Andrew.

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 Post Posted: Thu Oct 08, 2015 11:47 am 
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Joined: Tue Nov 27, 2012 11:59 am
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Location: Sunshine Coast, Qld
You could of course just fire the laser onto a wall in front of you and this is probably the way to get the most accurate result but hey at the time I didn't have a wall (too much crap in between the car and the very distant wall).

A further note would be to maybe do the alignment while the car has a normal payload. ie the driver is sitting in the drivers seat. A Tri Pod doesn't have a great deal of bump steer but try it with and without and see what the difference is.

Also if you are aiming for the most even tire wear then maybe run a smidge less toe out or maybe carefully set it to .25 of a degree when the drive or equivalent weight is in the drivers chair.

Below is pic giving a clue for how to get the upper ball joint to part company from the upright so you can tweak the camber setting.

Hit the upright bloody hard with a bloody big hammer while levering the balljoint upwards (leave the balljoints nut on a few turns still).

Attachment:
IMG_2141.JPG
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