CLUB OF CAR FANS
WHO TO POST IN AN ANGLE?
Everyone comes to the necessity of a visit to the “wheel alignment” stand
differently. One tire tires quickly wear out, the other “drags” the car to the side, the third is not happy with its handling, the fourth is happy with everything, but is used to following the instructions …
Mikhail KOLODOCHKIN, Vadim KRYUCHKOV
Having decided to visit several car service centers where wheel alignment is regulated, we pursued several goals. Firstly, it was interesting to check how different masters understand their task and by what means they solve it. Secondly, it is interesting to compare the data obtained when checking the same car on different stands by different teams. Thirdly, I wanted to compare practice with theory - do the numbers recommended in the literature coincide with the readings of the measuring equipment.
The experimental car is the editorial "ten." Debugged, technically sound, but with an innate tendency to "incontinence" vanishing disorder.
While the VAZ 2110 3 is pushed through Moscow traffic jams, let's recall the theory. Of the many suspension parameters, three are susceptible to operational adjustment: the angle of longitudinal inclination of the axis of rotation of the wheel is added to the vanishing and camber angles mentioned above - in everyday life it is also called the castor. Everyone has heard the first two corners, but few know about the third. For those wishing to delve into the purpose of all angles, we suggest reading our help.
Another point that is often forgotten. The angles of installation of the wheels depend on the mass of the car - it is no accident that the literature provides data for both the equipped and loaded cars. Recall that the curb weight characterizes a fully refueled, ready-to-use car without a driver, luggage and passengers. The payload in our case is 320 kg in the cabin and 40 kg in the trunk (manufacturer data). In relation to the "top ten" the difference in the angles of the wheels is reflected in the first two rows of the table.
And here is the first service - from here we will begin our journey, here we will end. The place was not chosen by chance - the accuracy of the stand and the skill of the mechanics were repeatedly controlled by us. In addition, it was here that we checked our "top ten" from the date of its acquisition.
… The master takes a portable compressor and checks the pressure in the wheels one by one. There is a question about the load on the trunk. There is some junk, but for fun we postpone unloading until later. Inspected the suspension - no comments. Sensors are installed on all wheels, a special strut includes a foot brake, the suspension is energetically pumped several times from top to bottom - you can record the first results (see table). Well, not really … We take out the trash from the trunk and ask for another measurement - this is how the next row of the table appears. Finally, the long-awaited adjustment follows, the data is entered into the Talmud, and we go to the next service.
Something is already clear - even the "gentleman's set", which you will find in almost any trunk (from the canister to the winch), can significantly affect the measurement results. We add here the anti-corrosion treatment of the body, anti-theft, “music”, covers, additional mirrors and headlights, rugs and other small things that are not noticeable at first glance - it turns out that extra kilos run out of nothing. Hence the conclusion: not a single car entering the adjusting stand, in fact, is neither empty nor full! Therefore, the above recommended settings should not be treated as a dogma … However, we seem to have arrived.
Local specialists use the CDS stand. We ask you not to adjust anything - just check the “correct angles setting” “before the long journey”. There is no problem - the car is driven into a pit, hung up with sensors, squeezed: soon the data is output to the printer. We ask an innocent question: does the position of the car relative to the stand affect the accuracy of adjustment? The guys shrug their shoulders and nod at the computer - there are a lot of megabytes in it, so let it think. And if something is wrong, then you need to go to the track and check the car on the go, and then fix it … Nobody asked about the condition of the trunk, nor did they check the tire pressure. The resulting figures were described as “normal”. Here are the pipes! Our “ten”, although capable of throwing a fortress, is not the same. We pay (for what?) And move on - around the corner one more post.
The rather unpresentable boxing did not inspire optimism, although the stand is quite modern - CDS 5C. Nevertheless, his owner plowed honestly - several times he drove the car back and forth, trying to mount the sensors correctly, installed a brake spacer, having previously covered the driver's seat with foil. He also clarified the loading of the trunk and walk with a manometer on all wheels - the employee would not have a price.
We face the same question about orientation: what if the car is at an angle to the stand? Thinking, the specialist got out, they say, the front sensors are connected by cables to the rear, and therefore any rotation of the steered wheels relative to the longitudinal axis of the car is immediately monitored, and the stand program is amended. It sounds plausible, but it became clear that such issues are also out of the ordinary … We enter the numbers in the protocol and go to replenish the statistics in the next quarter.
The employees of the next car service pleased us with the fact that they nevertheless adjusted the pressure in the wheels and asked if there was anything in the trunk. But for some reason they forgot to check whether the suspension is working. The further scenario did not change - all of the “asymmetric” problems mentioned above were unified onto the “electronics” of the Corgi stand, which was just giving out the next version of the state of our suspension. The numbers were considered normal - they wished us a happy journey. Thank you and return to the starting point of the route - to the John Dean booth.
Repeated measurement of the parameters showed that the camber of the left wheel “swam away”, and after it the convergence - a secondary adjustment is inevitable. Of course, it was carried out - data in the penultimate row of the table. For the sake of interest, we repeated the measurements, seating the passenger in the right front seat - the result closes the table. But what conclusions can be drawn from all this?
Only the team serving the CDS booth failed to measure. The rest caught the tendency of our "ten" to limp precisely on the left wheel. As for the absolute numbers, the biggest scatter is in castor and convergence, while the collapse is estimated quite accurately. Another result: the success of the whole procedure primarily depends on the experience of the masters and only secondly on the model of the stand.
Hence some practical tips. First: take care to unload the car as much as possible - a bag of potatoes in the trunk is capable of throwing out the “adjustment” money you have spent. Second: do not “catch fleas”, the last figures in the display indicate the resolution of the equipment, and not about the real characteristics of the suspension. It is much more important that the difference in indicators on the right and left wheels is minimal. Third: ask the master to adhere to the average figures within the tolerance (for front-wheel drive VAZ cars it is better to focus on data with a payload). Fourth: it is most reliable to regulate the wheel alignment every time on the same service - preferably, in your own, well-known shift.
DRIVING - the angle between the longitudinal axis of the car and the plane passing through the center of the steering wheel tire.
Camber - the angle of inclination of the wheel relative to the road surface in a vertical plane. If the upper part of the wheel is inclined to the center of the car, then the collapse is called negative, if outward, then - positive.