Logo rotaautoservice.com
Category: New cars

Two Meters Before

2024

Table of contents:

Two Meters Before
Two Meters Before
Anonim

Rear brake pads? But why bother to pay attention to them - it’s clear that basically the front ones decide everything … Is that right?

“No, not really,” the experienced tester from Dmitrovsky training ground shook his head convincingly. - I will say this: if when testing the front pads, the difference in braking distance between the best and worst brands is usually six to eight meters, then replacing one rear pads with others can easily add a couple more meters to this scatter. And the extra two meters, sorry, do not lie on the road …

Well, if there is an opportunity to somehow push a couple of meters of various kinds of obstacles - whether it be the rear bumper of a car braking in front of its nose or a soggy one that jumped out onto the road, then this is simply necessary! Let's try to choose …

… FROM THIRTEEN

What is required from the pad? No problem fit in your workplace - this time. To be able to brake well is two. And so that its wear is minimized as much as possible - these are three. Well, and the sufficient strength of the connection of the pads with the brake lining, as it were, is not discussed - these are four.

They decided to check the talents of the rear pads on the example of the VAZ for the “eighth” and “tenth” families: there are a lot of brands and common cars. The shopping trip was successful - out of thirteen sets, let's choose something. We use two samples from each set to determine the geometric dimensions and strength of the adhesive bonding of the lining with the block, and the other two to determine the frictional properties of the products and their wear resistance.

A LITTLE ON THE PROTOCOL

Checking the "geometry" of the pads, we determined the parameters that affect their collectability in the brake mechanism. For this, the experts used a technological device that allows you to measure the sizes of pads in pairs. Frictional properties and wear resistance were checked on an inertial stand STN-NAMI equipped with specially selected inertial masses. The temperature was measured using a thermocouple placed in the brake lining. The wear resistance of the pads was evaluated by their thickness at eight points before and after the frictional properties tests. Those who are interested in fundamental documents are referred to Appendix 15 of GOST 41.13–99 (UNECE Regulation No. 13) and GOST R ISO 6312.

We remind you that tests of the frictional properties of brake pads begin with their grinding. It is carried out at a speed of 60 km / h and a pressure in the drive of 5.0 MPa - the temperature of the onset of braking does not exceed 100 ° C. Lapping is considered complete when the running-in of the working surface reaches 80% of the entire pad area of the "active" block. Then measure the thickness of the pads. After this comes the turn of the “cold” brake test, preceding the heating cycle. It is carried out in two stages - first at a constant speed of 80 km / h and a variable pressure (from 2.0 to 8.0 MPa), then - at a constant pressure of 5.0 MPa and a variable speed (from 40 to 140 km / h). The temperature of the pads is approximately 100 ° C. The next test is the heating cycle: 15 brakes with an interval of 45 s. The pressure in the drive is 5.0 MPa, and the speed drops from 120 to 60 km / h. After that, repeat the program of "cold" tests, checking the change in the effectiveness of the brakes. The last stage is the next measurement of the thickness of the pads and the determination of wear resistance. The strength of the adhesive connection of the pads with the pad was checked on a separate pair of products of each brand.

It is clear that the “ideal” block should behave equally well in all modes, but, of course, this does not happen.

HOW DOES IT HAPPEN?

"Non-Euclidean geometry" is when parallel lines intersect, and the sum of the angles in the triangle rolls over 180 degrees … So, it seems that all the manufacturers of the blocks we got were working in some kind of curved space: how else to explain that all thirteen products didn’t fit the standard in geometry?

Of course, size to size is different. But when a company fails four out of four measurements - and this is exactly what happened with products No. 8, 11 and 13 - this cannot be explained by any non-linear space. Our man, of course, is able to stick any block into any drum, but somehow it’s not good … Ten products out of thirteen promise their owners a reduced resource and a long grinding - this is the fee for the reduced diameter of the blocks in the assembly. (By the way, if this diameter is very small, then the pistons can leave their workplaces, but this is the most extreme case.) With the curvature of the working surfaces directly affecting the runout and grinding times, things are no better - the same “hit percentage”. Slightly better with the size that determines the "fit" of the parking brake bar - it failed "only" nine products. And the dimensions of the bar, by the way, are standard - if the deviation is in the plus, then the handbrake simply will not drag on, if in the minus - the mechanism cannot be assembled. As for the last measured nomination related to the axis of the lever of the same handbrake, this size does not correspond to the norm of only six pads. As a result, pads No. 5 became the winner of the "Olympiad in Geometry" - before evaluating "excellent" they lacked 0.2 mm in one of the measurements.

However, not everything is so gloomy. Stunned at first by his frank disregard for rulers and vernier calipers, the blocks suddenly changed their minds and quite easily passed the exam in the main specialty - frictional properties. It should be noted that the pads reacted differently to the heating cycle - some improved their performance, some worsened, but overall the results are still positive. Perhaps, No. 5 looked worse than others: for example, at a speed of 140 km / h their braking torque amounted to 180 N.m, while pads No. 1 gave out 360 N.m in the same place. The same story was repeated when tested at constant speed: only 400 N.m against 650 N.m at No. 1 and No. 2. During the heating cycle, pads No. 2 looked better than others: their braking torque consistently exceeded 300 N.m, and the temperature was not more than 150 ° C. At the same time, products No. 8 showed the most intricate curve, dropping to the turn of 180 N.m. As a result, each brand received an integral quality assessment according to the behavior of the blocks before and after heating, taking into account the behavior during the heating cycle.

The specific wear of the pads, generally speaking, is not standardized. The most “hard Iskra” were blocks No. 6 with wear of 0.15.10–3 mm / brake, and the most “soft-bodied” No. 10 were 1.64.10–3 mm / brake: a tenfold spread speaks for itself. As for the durability of the connection of the pad with the pad, there can be no compromises: it was not enough for the brake drums to turn into such mills by grinding their own contents. And although all products are formally within the tolerance, the ratings will be different. For example, a pair of blocks No. 5 produced 3.4 / 3.5 MPa at a rate of 1.0 MPa - an excellent result. But the numbers 1.05 / 1.0, which are on the verge of a foul, are considered unfit - product No. 13 demonstrated them. The same applies to blocks No. 7: the numbers 1.4 / 1.0 MPa indicate instability of the parameters, and the margin obviously not.

Now let's try to compare the results of observations and count the points scored. If we apply the five-point system that is familiar from childhood to five nominations - geometry, frictional properties of “cold” brakes, frictional properties after a heating cycle, bond strength of a pad with a block and specific wear, it turns out that an ideal block could score 25 points in our examination. All other things being equal, the cheaper item takes the higher step - we believe this is true.

Alas, in our examination there were no ideal blocks (however, no one hoped for this). At the same time, none of the tested products deserved the “Marriage” label: all pads can be used in the “eights” and “ten” brake systems. And what is more important for you - price, frictional properties or, say, geometry - decide for yourself.

Image
Image
Image
Image

1 - Manufacturer's Declaration -

LPR, EEC

Estimated price - 400 rubles.

In terms of geometry - together with the majority, that is, every second size does not correspond to anything. But frictional properties are very good - perhaps even the best. The durability of the lining with the block is not bad, with a double margin. Specific wear is also acceptable. As a result - slowly, slowly, but turned out to be the best …

Score - 4 + 5 + 5 + 4 + 4 = 22

Image
Image
Image
Image

2 - The declared manufacturer -

"Beginning", Russia

Estimated price - 190 rubles.

The geometry is bad - only one size out of four turned out to be correct. The braking performance is very good, although non-linear. The strength of the joint is acceptable, and the specific wear is one of the lowest: it must be assumed that this will not affect the drums. And given the “pleasant” price, the overall rating was high.

Score - 3 + 4 + 5 + 3 + 5 = 20

Image
Image
Image
Image

3 - Declared manufacturer -

Lucas, EEC

Estimated price - 430 rubles.

Two of the four sizes did not meet the regulatory requirements. Frictional properties are good, especially after heating: the efficiency is the same at all speeds and linearly depends on pressure. The bond strength is good, and the specific wear is one of the lowest. But the price seemed overpriced.

Score - 4 + 4 + 3 + 4 + 5 = 20

Image
Image
Image
Image

4 - Declared manufacturer -

Fri-Tech, EEC

Estimated price - 120 rubles.

Geometry is a step away from a complete failure, but one parameter nevertheless met the norm. There are no complaints about the frictional properties - the curves are smooth, the numbers are decent. There are no special complaints regarding the strength, and the specific wear is quite acceptable. And the price is just wonderful, you can say - the most appetizing …

Score - 3 + 4 + 4 + 4 + 4 = 19

Image
Image

5 - Declared manufacturer -

ATE, EEC

Estimated price - 490 rubles.

The only set with more or less decent geometric indicators - only one parameter out of four did not reach the norm. After the heating cycle, the braking performance decreased markedly - not good. Specific wear is quite strong - third place from the end. But on the strength of the connection of the pads with the pad is the best.

Score - 5 + 3 + 3 + 5 + 3 = 19

Image
Image
Image
Image

6 - The declared manufacturer -

TEXTAR, EEC

Estimated price - 710 rubles.

The most expensive kit, which did not stop him from failing half of the geometric measurements. Frictional properties are not bad. There is practically no specific wear - however, you won’t rub drums up to holes … Strength - “like everyone else”. There is nothing to complain about, but such a product is clearly not worth the money.

Score - 4 + 3 + 3 + 4 + 5 = 19

Image
Image
Image
Image

7 - The declared manufacturer -

Transmaster, Russia

Estimated price - 200 rubles.

Anthropology at the firm clearly suffers - colleague No. 11 has failed in general, and here, only one out of four is normal. Frictional properties after heating increased, reaching very decent values. The bond strength in the two measured samples differed by 40%, with one block on the verge of a foul. Depreciation is low.

Score - 4 + 4 + 4 + 2 + 4 = 18

Image
Image
Image
Image

8 - The declared manufacturer -

OTA, EEC

Estimated price - 390 rubles.

With geometry in Italy is bad - not a single size fits the norm. But the frictional properties are very good - especially after heating. The strength of the connection can be set as an example - one of the best indicators. Specific wear is quite high. The price seems too high - what brand is it?

Score - 2 + 4 + 4 + 5 + 3 = 18

Image
Image
Image
Image

9 - Declared manufacturer -

Ferodo

EEC

Estimated price - 650 rubles.

The geometry is mediocre - half the dimensions are out of tolerance. The braking efficiency after heating slightly decreased, but the schedule became straightforward - at least put it in the textbook. Yes, and the pads themselves maintained the heating cycle with dignity: the braking torque remained high enough. Durability is good, wear is high.

Score - 3 + 4 + 5 + 4 + 2 = 18

Image
Image
Image
Image

10 - Declared Manufacturer -

VAZinterservice, Russia

Estimated price - 220 rubles.

Two measured sizes out of four hit the target. The exam in the "main specialty" passed without a shine: after heating, the efficiency fell significantly, remaining at an average level. Specific wear is quite high. The strength of the joint is not bad, but the difference in the two samples was about a third - and where is the stability?

Score - 4 + 3 + 4 + 4 + 2 = 17

Image
Image
Image
Image

11 - Declared Manufacturer -

Transmaster

(Comfort option), Russia

Estimated price - 260 rubles.

In geometry, it is a “deuce”: out of four parameters, all four fail. After the heating cycle, the frictional properties remained practically unchanged, remaining at a suitable level. The strength is not bad, but something is wrong with the technology at the company - the two products differ by 20 percent from each other … In general, it doesn’t matter.

Score - 2 + 3 + 4 + 4 + 4 = 17

Image
Image
Image
Image

12 - The declared manufacturer -

"Auto part", Russia

Estimated price - 180 rubles.

The shape of the pads is unimportant - only one size out of four is within the norm. The braking capabilities after the heating cycle decreased quite significantly, although they remained at an acceptable level. The strength of the connection is so-so, the specific wear is normal. On the whole … but on the whole there is nothing to note - it’s okay for rural areas …

Score - 2 + 3 + 5 + 2 + 4 = 16

Image
Image

13 - Declared Manufacturer -

unknown

(overlays - TIIR), Russia

Estimated price - 130 rubles.

Recommended:

New

Pragmatist

FIRMATIC FOR THE PRAGMATIC

Read More
UAZ -452

Through the eyes of the ownerUAZ -452Vladislav KOZKOHaving appeared in 1966, the UAZ-452 from (1985 - 3741) to this day remains almost the only light-duty off-road vehicle in the former Soviet Union. Judge for yourselves: the UAZ-452 is able to overcome snow cover 50 cm thick, move along tank tracks and carry up to 800 kg of cargo

Read More
Editor'S Choice
Best reviews for the week
Popular for the day