The front wheels on most cars are not set exactly parallel. Instead they
point slightly in or slightly out at the front - known as toe-in or toe-out.
The set of the wheels is called
If the tracking is incorrect the front
will wear out very rapidly
along the inner or outer edges. In severe cases the car's handling may be
by such an extent that it is impossible to keep the car on line.
Ideally the tracking should be checked and reset about every 10,000 miles
(16,000km), or sooner if you notice that the tyres are wearing unevenly. You
can either have a garage or tyre specialist do the job, or alternatively you
can buy one of the DIY tracking gauges that are on the market, such as the
Mobry tracking tool.
Checking the toe-in
With the car on level
, offer the tracking tool up to the wheels
and adjust it so that the arms sit against the front lip of each wheel rim. Make sure the tool touches the rim as close to the centreline as
Holding the tool in place, slide the pointer until it
zero mark on the
Lift the tool carefully away, and use it to measure the distance between
the rear edges of the wheel rims. You will have to slide the arm and
pointer out slightly until it touches the rim.
Then check the reading on the scale and compare it with the
How it works
The way in which the Mobry tracking tool works is very simple. It consists
of three pieces - a straight centre section and two cowhorn sections. The two
into the centre section, and are free to slide in and out. You can
then use the gauge to measure the distance between the front of the two wheel
rims and between the rear. By subtracting one from the other you are left with
the amount by which the wheels
in or out.
First find out what the setting should be for your car. The figure is
usually given in the booklet that comes with the gauge, but if it isn't check
with a workshop manual or your dealer. Make sure you get the right figure for
your car - it may be affected by factors such as power-assisted steering.
Also find out whether the car has to be loaded. On some cars the tracking
must be checked with no load in the car, while other cars have to have weights
in them again you can get the information from a manual or your dealer.
Prepare the car
Before you can check the tracking you need to check the steering and front
suspension to make sure that they are not worn. Wear in either of these systems
will give you a false reading.
Jack up the front of the car and support it on
stands. Then check the
steering and suspension
for wear by rocking the wheels in the 12
and 6 o'clock and 3 and 9 o'clock positions.
Follow this by checking the
for wear and adjusting them where
possible. Finally check that the tyre
are all correct. If all these
components are in good condition you can proceed to set the tracking.
Check the setting
Bounce the suspension a few times so that it is fully settled. Run the car
back about 30ft (10m) in a straight line, then run it forwards, again in a
straight line, to where you are going to measure.
Assemble the tracking tool by pushing the two cowhorn arms firmly into each
end of the centre section. You have to press in the
buttons to get each arm in. The arm with the pointer on should be fitted to the
end of the central tube with the markings.
If your car has a very wide track, or you are checking the tracking on a
van, the short arm without the pointer may not be long enough to do the
measurements. A second longer arm is provided for this.
Although you can do the job on your own, it is much easier if you ask a
friend to help. Make sure there are no balance weights or buckled rim sections
at the centre point of the wheel rim at either the front or rear.
If the wheels have to be set toe-in, position the tool at the front of the
wheel rims so that the arms are as near the centre-line of the wheels as
possible. Holding it there, press in the plastic button to free the arm without
the pointer and slide the arm out until it touches the wheel rim. Then do the
same with the pointer arm. There is a slot in the end of each arm that locates
on the wheel rim.
Now keeping the tool steady, carefully slide the pointer so that its tip is
against the zero setting on the scale. Making sure you don't
the arms, move the tool and line it up with the centreline at the rear of the
wheel rims. Press the arm without the pointer against one rim, then hold the
tool there and press in the plastic button to free the pointer arm and gently
slide it out so that the slot fits over the rim.
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