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Wheel alignment - string method



Chi

  Z4, VW172, R26
I think each system is only as good as the person doing it as chip said. It's all gone right over my head lol
 

imprezaworks

ClioSport Club Member
  Mk5 Golf GTI :)
I would love to have the time to get to learn how to do it though, sadly that wont happen.
 
  Cup In bits
Yeah I understand how it all works but the trigonometry goes straight over my head lol.

Can I go on the premise that on a 15" wheel then 7.5mm front to back difference is 1 deg toe out/in and on 16" wheel 3.55mm is 1 deg also.

I just bought the material to make a hanging rig for front and back, I just need to decide what's a good datum point to hang the rig off of.

That 15" figure doesn't seem right but I just multiplied Chips 2.5mm figure x3 to get a 1 degree.
 
  182/RS2/ Turbo/Mk1
MG Cup, just to put some actual numbers down for a 15" and a 16" wheel specifically.

2mm difference from the front to the back of the wheel on a 15" rim
(ie 1mm of toe from straight measured at either end as one goes in as much as the other goes out)

sin of angle = 2/380 (close enough)

so angle = sin-1 (2/380) = .30

ie 2mm difference in measurements from front to back (1mm of toe) is a tiny bit under a third of a degree




For a 15" wheel, here is a bit of a table of translations:
0.5mm toe (1mm difference in readings from front of wheel to back of wheel) = .15 degrees = 9 minutes
1mm toe (2mm difference) = .30 degrees = 18 minutes
1.5mm toe (3mm difference) = .45 degrees = 27 minutes
2mm toe (4mm difference) = .60 degrees = 36 minutes
3mm toe (6mm difference) = .90 degrees = 54 minutes
4mm toe (8mm difference) = 1.2 degrees = 72 minutes


For a 16" wheel, here is a bit of a table of translations:
0.5mm toe (1mm difference in readings from front of wheel to back of wheel) = .14 degrees = 8 minutes
1mm toe (2mm difference) = .28 degrees = 17 minutes
1.5mm toe (3mm difference) = .42 degrees = 25 minutes
2mm toe (4mm difference) = .56 degrees = 34 minutes
3mm toe (6mm difference) = .85 degrees = 51 minutes
4mm toe (8mm difference) = 1.1 degrees = 66 minutes



Those numbers of course are also the same for camber if you have a dead level surface to sit the car on and then measure from a plumb line, although thats not something I personally do.
 
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  Clio.
String (fluo coloured fishing line) and a couple of aluminium rods cable tied to the front and rear sections ( with the clams off) worked fine with a ruler when I use to set this up (many moons ago).
 

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  182/RS2/ Turbo/Mk1
That 15" figure doesn't seem right but I just multiplied Chips 2.5mm figure x3 to get a 1 degree.

Have put some example numbers up, 1 degree is approx 7mm difference measured front to back of the wheel, or 3.5mm of toe.

Thats PER wheel dont forget.


So for total toe, if you have 3.5mm of toe in per wheel you have:
7mm difference front to back on left = 1 degree
7mm difference front to back on right = 1 degree

Total toe = 2 degree
 
  182/RS2/ Turbo/Mk1
lol could take a few goes to get right.

@Chip-mk1 @grazo22 someone fancy making a in depth dummies guide to DIY alignment?

Im not convinced there is anything important not covered in this thread already?

Just to recap though:

You need two bars, one behind the car and one in front, with slots cut into them so you can slide string (I use coloured fishing line not actual string as its thinner so more accurate) onto them.
They MUST have the slots at the SAME distance, doesnt matter what the distance is so long as its a bit wider than the car, but it must be the SAME on both bars, otherwise the strings wont ever get parellel.
Then four axle stands to sit the two bars at the height of the centre of the wheel
And a steel ruler to measure the distance between the wheel and the fishing line

Make sure the distance from the centre of the two front wheels forward to the bar is the same, and then the same at the back, this ensures the bars are perpendicular to the car (within a few mm is fine on this measurement as a few mm has no difference that effects us on a bar that long)

Make sure the car is parellel to the fishing lines by ensuring the 2 front distances to the centre of the wheel to the line are the same and then again on the rear (each time you adjust one end it throws the other out by a smaller amount so you have to adjust both ends a few times till its perfectly central)


So you then have a rig where you have a line on each side of the car which is parellel to the centreline of the car.


Get the steel rule, measure the distance from the front of the wheel, and the distance from the rear of the wheel, and that tells you the toe on each wheel as per the numbers Ive already posted.

So for example if you have the centre of the wheel at 17cm from the fishing line, then you might get a reading of front 16.9 and back 17.1 from the front and back of the wheel, which would be a 2mm total difference, or 1mm of toe.

That 1mm of toe on a 15" wheel is 0.3 degrees.

Because it was the front number that is less (so its sat nearer the string than the rear) it means that you have .3 degrees of toe OUT.

If you measure the other side and get 17.2 front and 16.8 back, then you have 4mm total difference or 2mm of toe, and this time its toe in.
So you have .6 degrees of toe in on that side

.6 degrees of toe in and .3 degrees of toe out, means you have a total toe in of 0.3 degree



Anything still not clear, just ask :)
 

mad in general

ClioSport Club Member
  Clio 172 phase 2
image.jpgI made this for stringing the Clio. It allows you to move the car about when making adjustments.
Another bar just cabled to the front bumper then run the strings between them.

I haven't actually used it yet but no reason why it won't work.
 
  182/RS2/ Turbo/Mk1
View attachment 108844I made this for stringing the Clio. It allows you to move the car about when making adjustments.
Another bar just cabled to the front bumper then run the strings between them.

I haven't actually used it yet but no reason why it won't work.

The key thing is going to be that its absolutely centrally located, 1mm off and it will make all your measurements pretty useless.
 
  Cup In bits
That's what I'm away to make but out of powder coated white steel (cheaper than ally) with an adjuster to pull the strings taught and one that hooks in through the front grill.
 
Cheers Chip!

I just thought a guide would be good as it will stay around for longer and will be easier to find this thread will disappear in a week and come back when someone bumps it in about 5years time.

Ive made a quick link on my laptop though so its easily found.
 

mad in general

ClioSport Club Member
  Clio 172 phase 2
The key thing is going to be that its absolutely centrally located, 1mm off and it will make all your measurements pretty useless.
When I use it for the first time I am going to put a screw to stop the main bar from sliding. As the notches for the string will be cut exact distances apart then whenever one side of the car is aligned with the string I know that the other is parallel.
 
  182/RS2/ Turbo/Mk1
That's what I'm away to make but out of powder coated white steel (cheaper than ally) with an adjuster to pull the strings taught and one that hooks in through the front grill.
Ive just have weights on the end of the lines which means they are always tight.
 
  182/RS2/ Turbo/Mk1
When I use it for the first time I am going to put a screw to stop the main bar from sliding. As the notches for the string will be cut exact distances apart then whenever one side of the car is aligned with the string I know that the other is parallel.

I do similar in that I know what distance each side needs to be. So if I get one side right it's just a sanity check on the other to make sure it's the same.
 
  182/RS2/ Turbo/Mk1
If you have a pit or a 4 poster ( sadly I don't) it makes it a lot quick as you don't have to keep checking the string each time you make changes.
No need to jack the car up to alter toe though. Can do with wheel turned, but means moving the line out the way while you do then rechecking.

Its quite a time consuming process but still quicker than driving to a tyre place to have it done badly by someone who doesn't care.
 
  Cup In bits
Just get the car up on some wooden blocks to give you an extra 3" or so then there's no need to turn wheels for access. I am also going to make the front bar mountable across the strut tops to hang two plum bobs for camber changes, doing this means you can drive the car after changes to settle the suspension and your datum's are still there. Then a longacre bump steer gauge and you have all the gear to make geo setup with the wheels on or off.

I cant think of a simpler, cheaper way to do everything at home. All that will cost circa £200 and can be modified slightly to be used on other vehicles too.

I just seen these toe plates which are ideal for a quick toe check if you know the car is otherwise fine.

http://www.ebay.com/itm/Toe-In-Plates-/170844478703
 
  182/RS2/ Turbo/Mk1
Just get the car up on some wooden blocks to give you an extra 3" or so then there's no need to turn wheels for access.

You will still have to lie on the gorund to get at it so still need to move the string, and you wouldnt want to back the car up to put the blocks under it as you would effect how its sitting, even driving it only blocks could have that effect unless its two long blocks one for each side of the car.

I am also going to make the front bar mountable across the strut tops to hang two plum bobs for camber changes, doing this means you can drive the car after changes to settle the suspension and your datum's are still there.

If you can positively enough locate it thats a good idea with the strut tops, would be relatively easy to make some brackets off something like a pure strut brace to do the same too.

Then a longacre bump steer gauge and you have all the gear to make geo setup with the wheels on or off.
I setup bumpsteer just by removing the sprint and then putting a jack under the subframe, not perfect but it costs nothing.
(and using the same toe setup with fishing lines)


I cant think of a simpler, cheaper way to do everything at home. All that will cost circa £200 and can be modified slightly to be used on other vehicles too.



I just seen these toe plates which are ideal for a quick toe check if you know the car is otherwise fine.

http://www.ebay.com/itm/Toe-In-Plates-/170844478703

What I did to do similar was just a long piece of ally box with a 90 degree end on it, put it round the front and mark with a pen where it hits the tyre the other side, then do the same again on the back of the wheel.
But I'd sooner spend a bit longer and string it properly TBH as I view the tyre as a non ideal edge to work from.
 
  Cup In bits
What I did to do similar was just a long piece of ally box with a 90 degree end on it, put it round the front and mark with a pen where it hits the tyre the other side, then do the same again on the back of the wheel.
But I'd sooner spend a bit longer and string it properly TBH as I view the tyre as a non ideal edge to work from.

Thats what all the stock car guys do as it needs doing every race basically but that's a bit more agricultural than a circuit setup.

Yeah I don't know of any other way to check bump than to remove the springs? My lock is near dead on level (or close enough) so I can get away with blocks and plumb bobs, I'm going to build this rig, do a full geo minus bump and then get it hungered for a sanity check.
 
  182/RS2/ Turbo/Mk1
Thats what all the stock car guys do as it needs doing every race basically but that's a bit more agricultural than a circuit setup.

Yeah its fine to check its all "about right"

Mind you if you are just doing the one car all the time, so its just a tape measure on the front of the wheel, no need to compare to the back.
 

NorthloopCup

ClioSport Moderator
Optical ones? They don't work on lowered cars IME and again aren't mobile ;)
Yes mate optical ones. They work very well on all the lowered cars I've done with mine mate. Never had an issue transporting them either!

Lets not forget they have the conversion table on them as well - ideal if your s**t at maths! Flol!
 
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  Cup In bits
Yes mate optical ones. They work very well on all the lowered cars I've done with mine mate. Never had an issue transporting them either!

:pHaha funny bugger, If you move the car they need reset again which is the bonus of the pole rigs. The bumper gets in the way of the mirror on most cars I have done, you need a good 100mm? Do you use them so the read out is under the sill or something
 

NorthloopCup

ClioSport Moderator
:pHaha funny bugger, If you move the car they need reset again which is the bonus of the pole rigs. The bumper gets in the way of the mirror on most cars I have done, you need a good 100mm? Do you use them so the read out is under the sill or something
Well you will leave yourself open for the smart arse comments! Flol! Tbh, the resetting of them doesn't bother me anyway. I've done it that many times I know how much to move the track rods to get very close to the desired setting. I also have a string setup that hangs off the car. That's the weapon of choice when I want to see how much of a shim I've got to fit to one of the cadburys rear beams.
With regards clearance you just turn the round and read them backwards, or just adjust the 'fingers' that touch the wheel so they give maximum reach to push the mirror/eye piece as far forward as possible.
 
  182cup & 172 racecar
Same thing but without the need for axle stands and you have mobile datums with this.

View attachment 108872



Optical ones? They don't work on lowered cars IME and again aren't mobile ;)

I see that Morgan, but like everything, it isn't always that easy.

That picture shows it attached to the car, if a car has been corner weighted, it won't be level.

What if the car has had a bash etc, thats the only problem with using anything that is connected to a part of the car as a reference point.
I always get mine set up with a Hunter type laser machine, then check it against a pair of Dunlop gauges (which, like Mark, I never have any trouble using), then check again with axle stands and string.

The string method then for the rest of the year, as this is the only thing that is mine.
 
  Cup In bits
I see that Morgan, but like everything, it isn't always that easy.

That picture shows it attached to the car, if a car has been corner weighted, it won't be level.

What if the car has had a bash etc, thats the only problem with using anything that is connected to a part of the car as a reference point.
I always get mine set up with a Hunter type laser machine, then check it against a pair of Dunlop gauges (which, like Mark, I never have any trouble using), then check again with axle stands and string.

The string method then for the rest of the year, as this is the only thing that is mine.

It is that easy if you make it adjustable and it stops the need for fiddling with axle stands which is what takes the time the other way. Every time you roll and bounce the car after a change you have to setup the axle stands again.


My rig will only be used in the same way as yours Tony, as a quick sanity check and for also adjusting camber/toe track side if needs be. Corner weights will be done by a garage until I can afford a set of scales.


I think the fact that the BTCC lads use them at the track speaks volumes.


Re Dunlop gauges; we must have different models as there is no chance on using our set on anything that's lowered and they're not long enough to go past the front edge of the bumper :S
 
  182cup & 172 racecar
Morgan, get yourself 4 bits of thin ally (2mm eg), put some grease between them, then put them under the front wheels. This will then move slightly when the car is lowered onto them.

I find my car doesn't move anyway, so pointless moving it backwards and forwards.
 
  182/RS2/ Turbo/Mk1
When I adjust the tracking on mine, despite steering the wheel to gain access and steering it back, it never normally moves, I just lift one piece of string carefully off so its out of my way and then lift it back on again and give a quick sanity check with the steel rule.

I like it to be as simple as possible TBH, far less effort to store a couple of bits of bar and some string than some elaborate and potentially fragile bolt on rig. But either way is fine, just a case of whatever you prefer.
 
  Cup In bits
Morgan, get yourself 4 bits of thin ally (2mm eg), put some grease between them, then put them under the front wheels. This will then move slightly when the car is lowered onto them.

I find my car doesn't move anyway, so pointless moving it backwards and forwards.

Yeah thats a good idea, I did think about wheel wheel cups but there expensive.

Yeah my race car only moves 20mm in droop even when you jack it up, high rate springs won't move like you say.
 
  Cup In bits
how do you account for the different track widths front to back?

You have the same length bars front and back with the string positioned to make a perfect rectangle, you then square that rectangle to the car on the same point left and right until the measurements are equal on both axles.

The measurements are bigger in the rear as the string ends up further from the wheel with the wider front track that FWD cars have, its the split between the measurement from the front of the rim and the rear of the rim that gives you the angle through trigonometry using the string as the square.
 
  182/RS2/ Turbo/Mk1
how do you account for the different track widths front to back?

You aren't matching the front to the back so it doesn't matter.

The width apart the string are is fixed by the bars they locate on.

So all you have to do is get the car in the middle of them.
By making front left match the front right. And rear left match the rear right. There is NO comparison required between front and back.

That is enough to ensure it's parellel. That's all you need so you can then measure each wheels toe relative to the string like Morgan says.
On my 172 turbo the front is about 50mm wider than the back. Still no problem.
 
  182
r****d alert!

Please excuse my piss poor paint skills lol and wording of stuff.

If i was to set the string at 270mm off the front side and rear side of the rear wheels. All i need to do then is set the fronts to equal mm of distance to then run 0 degree toe??

So say 230mm frontside and backside of the front rim? And is perfectly ok for road use?



measurements are just an example.

align_zpsdf5fd9f4.gif


Cow me near on an hour to set it up with 4 axle stands so i hope so......... i just done a full suspension refresh bar tie rods and ends (fairly new) Steering wheel is **** on centre now with no pulling either way and handles sublime:cool:
 


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