[apk919]

Usually, I use turbophil's method to measure toe: http://www.lotustalk.com/forums/f91/little-diy-alignment-45655/ but after talking to Carl, I though I'd also try the method shown in this post: http://www.lotustalk.com/forums/f91/little-diy-alignment-45655/#post795972

I get very different results using the two methods anic:

It's easy to explain... the two methods do not result in parallel strings, at least with the wheels that I'm using (RAC Monolites). In fact, there's a 0.62/0.64 (right/left) degree difference in the angle of the strings to each other... and that's a lot, since the range of rear toe settings is 0.16 to 0.24 degrees.

For example, using the first method, I get 0.20 degrees of toe in on the left rear, with the second method, I get 0.44 degrees of <b>toe out</b>!

I'm very confident that I'm doing the first method right, as I've compared measurements to those taken from a laser alignment rig. I'm not sure I'm doing the second method correctly...

Any thoughts anyone? Is there something about the offsets of the RACs that makes the angle greater than with other wheels? Or is it simply that the different front/rear track of the car makes the second method questionable?

EDIT: The front/rear track of the car is spec'd at 1457/1507mm (front/rear)... that's exactly the angle I'm measuring: arcsin((1507-1457)/2)/2300 = 0.623 degrees

EDIT2: xtn pointed out this potential problem in this post: http://www.lotustalk.com/forums/f91/little-diy-alignment-45655/#post795985... is it possible that Jack's car has spacers on the front wheels? If they were around 25mm it would completely neutralize the difference in track, and make the method accurate for his car.

Pics...

1) Sighting down the two strings, first method on the outside, second method on the inside. Even with the "vanishing effect", you can tell they are diverging...

2) Looking straight down on the left wheel... here it's easy to see the difference in angles

 

[SirLotus]

If anyone is interested, I have "Trakrite", drive over Toe in / Toe out, wheel alignment gauge for sale.

 

[apk919]

If anyone is interested, I have "Trakrite", drive over Toe in / Toe out, wheel alignment gauge for sale.

What kind of accuracy does that thing have? I can reliably get within +/- 0.02 degrees accuracy with turbophil's method... (Lotus spec's the tolerance at rear side to side toe difference as 0.04 degrees)

 

[carl]

remember the way i set up the strings not give you a total toe measurement.it only allows you to get the rear toe even side to side. the way you have it set up the distance from the string to the front of the rear rim should be the same side to side. make sure you have the front wheels centered before you take any measurement .carl

 

[apk919]

remember the way i set up the strings not give you a total toe measurement.it only allows you to get the rear toe even side to side.

Ah, OK... that's what I missed. Then you can't measure absolute toe that way, correct? On the other hand, you can be sure that your toe is balanced.

the way you have it set up the distance from the string to the front of the rear rim should be the same side to side. make sure you have the front wheels centered before you take any measurement .carl

Yes, I was careful to do that.

It was a very useful exercise... I think I was able to prove (at least to myself) that I was doing turbophil's method correctly by comparing measurements between the two. BTW, it takes much less time to set up and use your method...

Thanks again Carl! :bow:

 

[carl]

remember the way i set up the strings not give you a total toe measurement.it only allows you to get the rear toe even side to side.

I meant "do not give you"- good you could understand it's not fun getting old. carl

 

[Mark A]

turbophil's method is correct.

Carls set-up is wrong for the Elise as you don't get a correct angle on the front or rear, as you have found the strings are convergent towards the front therefore you can't set the toe as the strings are not parallel to the centre line of the car. Okay, it lets you set the toe even side to side but you have no idea what the actual toe is (if they aren't even which do you assume is correct?) so TBH it's pretty pointless.

 

[carl]

turbophil's method is correct.

Carls set-up is wrong for the Elise as you don't get a correct angle on the front or rear, as you have found the strings are convergent towards the front therefore you can't set the toe as the strings are not parallel to the centre line of the car. Okay, it lets you set the toe even side to side but you have no idea what the actual toe is (if they aren't even which do you assume is correct?) so TBH it's pretty pointless.[/QUOTE

My set up is not to designed measure the toe it only gives you a way to even out the rear toe(thrust ) . to measure the total toe i use a toe bar that measures the difference between the front and the rear of the rims. you could have the total toe correct and one rear wheel toed out and the other in. then the car dog tracks. carl

 

[plastique999]

andy, what were your final toe measurements?

 

[apk919]

I have to remeasure toe tomorrow, since I've just finished putting on the Sector111 steering arms (-1.5 degrees front camber). I'm shooting for 0.25mm front toe out. Rear toe is 1.6mm toe in for each side.

EDIT: 0.25mm toe out in front it is...

 

[turbophil]

Back from the dead thread

A few months back, I purchased one of these

For the last few years, Ive just used a machinist's rule, but that little gadget from ART has really made the alignment process easy. It's surprising how much faster I can accurately do alignments with it than with out it...

Just thought I would pass it along... Nothing new, just a product review for a cheap but uber handy tool:up:

It can be purchased here: Pegasus - The "Dream Stick" Toe Measurement Tool from A.R.T.

Good Day,

TP