tyres: tracking

Hello again,

As you may remember, I've been posting questions here about tyres recently. First I wanted some new tyres for my car and I needed help understanding the new rating labels and then my other half had a puncture in one of her tyres. Thanks for all the help with those posts.

I went ahead and bought a pair of tyres for my car and the fitting station offered a "free alignment check". I need some help interpreting their results to see whether I have a problem or whether it's just a tool to make them more work.

They have printed me a pretty sheet with camber, caster, and toe measurements for the front wheels and camber and toe for the rear. I have no idea what these should be. Where would I find these out? Would they be in Haynes?

The garage has colour coded the results and all are green except for: the offside front toe, which is minus 0 degrees 11 minutes, and the rear nearside toe which is minus 0 degrees eight minutes.

There is also a front "total toe" of minus zero degrees and five minutes and a "steer ahead" of zero degrees eight minutes.

What does that mean in theory and what does it mean in practice?

There is also a box for thrust angle, which is minus zero degrees one minute and that is neither green nor red.

I took the punctured tyre to a different garage for repair and asked them about the tracking on my car and they said if I wasn't noticing any wear problems, not to waste my money (though I didn't show them the print out of results as I was embarrassed to admit buying my tyres on the basis of cost from elsewhere).

TIA

Reply to
Fred
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much will depend on whether it is a Peel or a Hummer.

Reply to
Mrcheerful

Mondeo.

Reply to
Fred

Probably, or a quick google.

That's all you need to know. They green flag those that are within spec.

Is there any other figure for those? Are they red?

Toe is exactly what it sounds - is the wheel "pointing out" or "pointing in". Strangely, they should rarely be absolutely parallel.

OK, that's the one that's really important on the front toe - basically, if one side is toeing out too much and the other toeing in the same amount too much, then it'll all balance out, but your steering wheel will be on the wonk. Whether that actually matters depends on whether your car's new enough to have electronic bottom-wipers with a steering wheel position sensor. If not, then it's merely a cosmetic thing.

That's a new one on me.

Reply to
Adrian

all the suspension on a Mondeo is of such a floppy design that merely repeating the test after a short drive is likely to give a different set of results. The figures you give are so close in practical terms to the correct ones that there is no need to worry about them. If it starts wrecking tyres or fails the MOT is the time to get bits replaced.

Reply to
Mrcheerful
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Me too; this site:

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has a definition of sorts.

Chris

Reply to
Chris Whelan

Ah. Steering wheel wonk. 8' is somewhere around invisible, I suspect.

Reply to
Adrian

Yep. I honestly don't believe it's possible to measure a car's geometry to that degree of accuracy by referencing the edges of the wheels.

Chris

Reply to
Chris Whelan

Its more than likely within factory tolerance, there are not many adjustments on cars anymore unless you buy adjustment kits. The big problems come with parts/bushes or accident damage.

Read this it may give you a better understanding

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Reply to
Rob

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> More than you'd think. Time was practically everything had non-adjustable rear suspension, but my Leon's is. Wouldn't be surprised if a few other cars with independent rear suspension are too.

Reply to
Chris Bartram

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the mondeo has a few, but the overall design is weak.

Reply to
Mrcheerful

That is rather meaningless. Front toe is the difference between the wheels, not of the wheels from the centre line.

Reply to
DavidR

Red - port left Green -starboard right

Reply to
Rob

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Apparently the Golf V/A3/Leon rear suspension is very similar: AIUI VAG poached a Ford engineer.

Reply to
Chris Bartram
[snip]

So you keep saying. However the only real weakness appears to be subframe bushes that fail prematurely and that can be fixed by using polybushes. Bushes seem to be a Ford weak spot. I had similar problems at 100k on my Exploder. I replaced using a Polybush kit and then ran for 170k more without a problem. The current owner said it was the best handling of the ones he tried.

Reply to
Steve Firth

Well it's good to baffle the customer.

To get toe from independent measurements of the wheel alignments they have a left and right alignment. The steering wheel should have been jammed on dead ahead. A left and right "toe" tells the technician how much to adjust each wheel to give correct toe AND get/keep steering wheel centered. People tend to complain if the steering wheel isn't dead ahead when going straight as it would be when all the toe (proper) is set from side only.

Now at the rear it is useful as toe on each wheel is usually changed independently. Instead of centering the steering wheel they are setting the "thrust angle". That also affects the hands off direction of the car. With RWD it will also produce a difference in direction that depends on thrust or braking from wheels.

Even if there is no apparent means of adjustment, an adjustment may be possible by shimming one or more of the suspension mounts.

Front struts can be adjusted for camber by undersize bolts with cams, called "camber bolts".

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The OEM versions have full size bolt shank and use an eccentric head and keyed washer that sits in a welded on channel plate [ on the strut. But for some people even adjustable top mounts are not enough.
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Reply to
Peter Hill

Or the customer to baffle the 'tech'. ;-)

(As an aside ...) When the Mrs clipped a Daimler Sovereign when reversing our Mk2 Escort based kitcar (our o/s/r wheel rim caught the Daimler n/s/r hub, pushing our rear axle forward and (unbeknown to me at the time) bending it round the prop shaft (when it hit the gearbox), bending the damper and breaking one shackle at the same time), I noticed some 'tracking' type wear on the rear tyres some 1500 miles later.

I took it into KF and asked them to measure the tracking on the rear wheels (just to satisfy my mind that the rear axle tube had indeed been bent). Long - short, they didn't understand the request and invited me to do it myself, so I did. ;-)

I think it was about 1.5 deg toe in on the o/s and about .5 on the n/s (because the impact was on the o/s). One bright spark then suggested (after initially telling me their tracking kit couldn't measure the rear wheels), 'reverse at high speed and pull the handbrake on hard to bend it back ...'

I found a straight second hand axle tube and swapped my stuff over. Simples. ;-)

Cheers, T i m

Reply to
T i m

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Nah, you want to do it properly

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Reply to
Duncan Wood

Clearly. Though it is only relevant to the person actually carrying out any changes but of no relevance to the customer wanting to know whether tracking is correct. If the steering wheel is not centred when the wheels are, it is essentially a cosmetic matter.

Reply to
DavidR

There are polybushes and polybushes. (different polyesters)

I have used them on several cars and have not been particularly impressed, some very hard, some soft and others which collapsed and deteriorated over a couple of years.

Now I only use them when original rubber bushes are not available.

Reply to
Rob

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