onger dodgy to measure
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I/ Measuring toe-in, that most critical of steering alignment settings, has always been a dodgy business despite the advent of lasers and computers to help the operator. Yet there is a device that is simple to use, can be carried in one hand, costs under £200, and above all, works.
Although major manufacturers are starting to recommend it now, the SPQR Engineering Trakrite is only just beginning to find favour in fleets. Strangely, one of the reasons for this reluctance is the very simplicity of the all-plastic alignment gauge. It does just look too good to be true, and some fitters have been convinced that nothing so simple could possibly be accurate.
The pedigree of the Trakrite is impeccable, with the original idea dating back to the Weaver plate of 1929, and via the Churchill gauge of post-war years. All work on the same principle, where the side force caused by incorrect toe-in moves a plate set on a low friction surface.
The Trakrite is a dynamic device, that is, the vehicle is driven onto the plate and a pointer indicates whether the alignment is correct. In essence it is a simple go/no go gauge, and needs no complicated setting up before use.
All vehicles can be tested in less than three minutes, except for twin-steers where the procedure is a bit more complicated. Indeed there are those who believe that twin-steers are impossible to set up correctly by any means. Managing director of SPQR, Peter Tornkins, is not one of these, however, and he claims that twin-steers can be done in 10 minutes, and Leyland seems to agree with him having issued a service bulletin on the subject.
Trakrite was used in its thousands by ATS, the tyre-fitting giant, in its smaller version. This HGV model is suitable for all heavy trucks and small commercial vehicles down to about one-tonne payload. It could equally be used for smaller vehicles, but the maker says that it would be less accurate at the lower weights.
Using Trakrite is very easy, although there are a few precautions to observe. First, it can be used only on a flat and level surface. This as good as prevents outside use, and in any case there must be a clean and grit-free surface.
The pointer which shows a position for perfect alignment, must be in its central position, and the top plate must be free to move from side to side after the removal of the retaining peg. If any dirt or grit has accumulated the whole item can be flushed with clean water.
A reasonable amount of space is re. quired so that the vehicle can be lined ur in the straight-ahead position. This ie sometimes easier said than done aE manufacturers have a nasty habit of put, ting the steering wheels on a spline ot two away from the true centre. Do noi be misled by the position of the steerini wheel spokes .. .
The bevelled edge of the Trakrik now needs to be placed at right angles k the wheel to be tested. This is besi done by using a straight edge, but thiE must be removed before the test. The pointer faces outwards where it can be seen as the test is done.
Next the vehicle should be reverse( away from the Trakrite so as to allow lot one complete revolution of the mac wheels. This effectively takes an preloading off the geometry, as will have taken place after braking. This reversirq manoeuvre should be done with hands of the steering. Then you are ready for the test. The getting ready procedure wit have taken about two minutes so far.
Now drive forward — again with hands off — onto the plate at a steady speed o about walking pace, until the wheel hae completely passed over the plate. The top plate will, if there is any sideforce al all, have moved against the bottom plate and the pointer will show instant]) whether there is toe-in or toe-out.
A small amount of tolerance ie permitted in the pointer position, but it it perfectly possible to get a zero reaclim with most vehicles. The track rod ende are adjusted until the test comes LIT right, and with a bit of practice this car be achieved with no more than a couple of tries.
The advantage of this method is tha since it is looking for the true straight. ahead position under running loads, al the variations that normally influence alignment such as make and type of tyre: and body loading characteristics, are eli. minated.
This is where the time-saving reall3 comes in for there is no need to consul the manual (are you sure this is the righi model?) to get a figure to set. And there is no fiddly reading off scales marked is tiny figures in minutes and degree; (some operators forget which is which) So there is far more chance that the setting will be done correctly without having to depend on the human element. It also means that anyone who can drive can do the test, freeing highly technical.
The very ease of this method of alignment means that it is much more likely to be done at all, as the test can be done as the first part of the vehicle's normal service as it drives into the service bay. Better tyre life is assured more by knowing when the alignment is going out of spec than just waiting until the results show up with a unevenly worn or feathered tyre.
Workshop went to look at the Trakrite being used in a busy branch of the huge Ryder Truck Rental organisation. Here, with the assistance of branch manager Melvyn Wiltshire we ran the test on a Dregistered Mercedes 307. The check took just three minutes, and showed that the vehicle was within acceptable tolerance, but very slightly toed-in.
Wiltshire said he had found the device most useful in the year-and-a-half that they had it in the branch, adding that the main difficulty was getting the staff to believe that it was as good as any other method. Ryder's Trakrite was hanging up by its handle on the wall, looking just what it is — a slab of black plastic. No bells, whistles or flashing lights, and precious little to go wrong either. It can show up bent track rods just as well as a E400 gauge, says Wiltshire, and its ease of use in a depot where everyone of the 180 vehicles is normally inspected every month, gives it great potential.
No resetting of the Trakrite is necessary after its use, and it is suitable for vehicles up to a maximum load of six tonnes per wheel. Tyre pressures need to be checked before the test.
The depth of the working parts of the mechanism is just under 1.6cm and the plate itself is 81cm long by 48cm wide. A one year's unconditional guarantee is offered and the price is £185 plus VAT.
Trakrite is a deceptively simple device which can make workshop life easier, and it holds out the hope of reducing tyre bills. It is now approved by Leyland and Bedford as a service item and other manufacturers are said to be testing it too. Trakrite is available direct from: SPQR, Rowlands Castle, Hants P09 6AT.
• by John Parsons