Alignment Results Help

[rtb998]

Just had alignment carried out on my 2005 V70.

Can anyone tell me what, precisely, is the measurement shown for the toe?

Is it the difference in distance between the edge of the rims, or the tyres or some something else.

At some stage the machine has to convert these to an angle as thats how Volvo publishes the specification. (0.0 to +0.2 degree front, 0.0 to +0.4 degree rear).

Also could someone confirm that these angles refer to each wheel and not the total for both wheels.

[Laird Scooby]

Originally Posted by rtb998

Just had alignment carried out on my 2005 V70.

Can anyone tell me what, precisely, is the measurement shown for the toe?

Is it the difference in distance between the edge of the rims, or the tyres or some something else.

At some stage the machine has to convert these to an angle as thats how Volvo publishes the specification. (0.0 to +0.2 degree front, 0.0 to +0.4 degree rear).

Also could someone confirm that these angles refer to each wheel and not the total for both wheels.

The toe measurement is shown in the top row for the front wheels and the 4th row for the rear wheels. I don't know the settings for yours so can't comment on whether they are correct or not but given that the machine is presumably preprogrammed for a whole database of cars and the readouts are shown in green, they are in tolerance.

Generally speaking the toe measurement is for the total toe of both wheels on an axle, for example on mine the front is 0deg 18' +/- 8' so the total toe in will be between 10' and 26'. Last time i set the alignment it came out at 11' so i called it good then hit another pothole the next day and it needs doing yet again!

However i don't have a 4-wheel alignment machine so don't have the benefit of being able to measure individual wheel angles which is what you have there as well as camber angles and vector angles. The total toe is shown between the wheels shown on the diagram at +2.6 front and +1.7 rear.

I'm guessing this is minutes (') and the figures you've quoted from Volvo of 0.0-0.2 front and 0.0-0.4 rear are in decimal points of a degree, this translates to 0' - 12' front and 0' - 24' rear, for the sake of calification, one minute is 1/60th of a degree and one second (") is 1/60th of a minute.

On that basis, i'd happily suggest all is well but to be honest, without any units specified, it's all open to interpretation so i could be wrong and someone else may be able to shed a different light on this.

[rtb998]

Thanks Dave,

You are right that there's a database of cars programmed into the machine but the operator can overide some of the parameters.

The numbers for toe on the sheet are distance in mm not angles in degrees.

What I find strange is that the car appears to have been set with more front toe-in relative to the rear, when the Volvo spec is the opposite. I appreciate that after accounting for tolerances, everything may still be OK.

However without knowing what these toe numbers actually measure then its impossible to find the correct angle.

I did some basic trig calculations using my rim diametre (16"). Assuming! that the numbers refer to difference in rim to rim distances then the toe would just creep in under the higher end of the spec. If the measurement relates to the tyre diametre (205x55x16), then the toe would be very near the middle of the specification.

Its a possiblity that the distance is the differences between the instruments sensors which I think would make the toe-in even less.

[Laird Scooby]

Originally Posted by rtb998

Thanks Dave,

You are right that there's a database of cars programmed into the machine but the operator can overide some of the parameters.

The numbers for toe on the sheet are distance in mm not angles in degrees.

What I find strange is that the car appears to have been set with more front toe-in relative to the rear, when the Volvo spec is the opposite. I appreciate that after accounting for tolerances, everything may still be OK.

However without knowing what these toe numbers actually measure then its impossible to find the correct angle.

I did some basic trig calculations using my rim diametre (16"). Assuming! that the numbers refer to difference in rim to rim distances then the toe would just creep in under the higher end of the spec. If the measurement relates to the tyre diametre (205x55x16), then the toe would be very near the middle of the specification.

Its a possiblity that the distance is the differences between the instruments sensors which I think would make the toe-in even less.

It's the difference between the front of the rims at centre height and the rear of the rims at centre height, this explains it better than i can at the moment :

http://www.enginebasics.com/Chassis%...ing%20Toe.html

Assuming those settings on the prinout are within tolerance, it doesn't actually make any difference if they've been set with more toe in on the front than the rear, in fact it may be beneficial if some of the bushes are a little worn as the wheels will pull parallel under power rather than pulling into a toe-out situation under power.

Your V70 is FWD so the front wheels will be pulling the car forward and depending on your exact suspension set up, he may have accounted for a bit of wear in the bushes.

[rtb998]

Thanks again Dave,

Yes, I agree that its normal to think of toe being measured between the rims but it doesn't have to be and the more I look at pictures of laser equipment I don't see how they would do it. The machine may well calculate the rim to rim difference but as the Volvo spec is given as an angular measurement, there's no need to do that.

I didn't say in my original post for reasons of brevity, that I'm familar with car alignment. I've been setting toe, camber, castor, ackermann, SAI on competion cars for many years. I've used the prehistoric Dunlop tracking guages though now tend to use trammels or string. It just that the V70 is too big for my flat patch and gauges. Plus I'm getting too old to scramble about under cars on the road.

I guess I'm hoping that someone has a bit of insight into the Supertracker equipment.

Thanks

Richard

[Laird Scooby]

You're welcome Richard, i'm not sure how the Supertracker actually calculates things, i know my Trackace works on the included angle and laser alignment via a mirror and doesn't need a big area round the car.

[rtb998]

I looked at the Trackace a couple of years a ago and thought about buying one. But these days everything I set up is zero toe, zero camber and very narrow equal front/rear track so a trammel gauge and a long straight edge does the job. Except the Volvo.