Description and technical characteristics of the MMZ 81021 trailer

Hi all! Today I would like to touch on a topic that will in many ways take us back to the past, but at the same time will allow us to remain in the present. After all, we are talking about the MMZ trailer. This is a Soviet-style development that has a long history of existence.

Although the manufacturer’s arsenal included models such as 8113, 81024 and even tractor trailers marked 771 and 771B, the main asset of the manufacturer is still considered to be model 81021. It is this trailer that we will focus on, and also compare its characteristics a little with the more advanced version represented by 81024.

Just looking at the photo, you can understand that you are unlikely to be able to buy a new MMZ. Just recently I came across an advertisement with an offer like selling MMZ in perfect condition. The condition is really good, there are springs, a well-preserved awning and even polished wheels. But now almost all MMZ in this form are alterations, where spare parts were changed, the same lights, springs, etc. were restored.

General information about MMZ-81021

The MMZ-81021 trailer is a serial product and can be used with any VAZ model. The peculiarity of this model is the use of a large number of parts from the Zhiguli car.

When assembling the trailer, the following components were borrowed:

Trailer MMZ-81021

• tires;
• suspension;
• wheels and tires;
• wheel bearings.

This configuration of the MMZ-81021 made it possible to carry out repair work on the device together with the car, without using additional tools and spare parts. The popularity of the model among the general public was due to the ability to use the MMZ-81021 with any mechanical transport due to the unified trailer attachment of two varieties.

Due to its size, the design made it possible to transport large or heavy loads, and the presence of high sides ensured their safety without additional fasteners. The cargo trailer included additional arches on which a protective awning was installed.

The use of a cargo platform limits vehicle speed to 80 km/h. The driver must have a trailer registration document.

Purpose

The first serial trailer from MMZ was the immortal model 81021. It was created specifically for installation on VAZ cars.

Initially, the model was developed as a tow hitch for the VAZ 2101, that is, the Soviet Kopeyka. It is not surprising that the vehicles received similar shock absorbers, identical bearings and even identical wheels. In fact, all the components of the chassis for 81021 were already there. All that remains is to install them on the body and make some modifications. Thus, the plant came up with an ideal partner for Kopeyka, which the owners of these cars immediately took advantage of. They started buying 81021 very quickly and actively.

If we talk about the dimensions of the pioneer, they were 1850x1600 mm. This made it possible to transport all kinds of cargo, making the trailer universal and multifunctional. The design provided for a side with a height of 450 mm and an awning, which was installed on a metal frame. As a result, the total volume of the MMZ was about 1200 liters.

Soon trailers began to be adapted for use on vehicles of other smaller classes. They were intended for cars that were then produced by factories such as AZLK, VAZ and IZH.

Interestingly, the trailer from MMZ, intended for AZLK, received the same design elements as those used on the vehicle itself. For such vehicles, the load limit was set at 135 kilograms. It should also be noted that the GAZ plant produced models for middle-class cars. That is, MMZ made trailers for the then elite and for many inaccessible Volga. The load on the coupling device was a good 50 kilograms, and trailers were allowed to be operated at speeds of up to 80 kilometers per hour.

At one time, 81021 was recognized as a necessary and extremely useful device. This was due to the fact that the trailer could perform several important functions.

Now on Avito and other portals you can find used trailers from different manufacturers, or purchase a new vehicle from a huge assortment. Back then the choice was limited.

But in fact, people did not need a huge choice. They were quite satisfied with the opportunities that MMZ provided them with. After all, with the help of their trailers it was possible to:

• deliver industrial goods;
• transport food;
• transport agricultural products;
• deliver construction materials.

Due to its versatility, MMZ has solved a number of transportation problems. The awning protected from dust and precipitation, the spacious body made it possible to transport fairly large quantities.

Flatbed trailer design

Fastening the hub and wheel of the MMZ-81021 trailer.
The chassis of the MMZ-81021 consists of an all-metal axle with suspension and space for hub bearings. Tube tires and wheels, as well as telescopic shock absorbers, are used from the VAZ 2101 car. To extend the life of the rubber and allow easy rolling when operating the trailer, it is necessary to ensure a pressure of 1.7 atmospheres.

The design includes suspension elements that are necessary to reduce vibration when driving. The spring suspension has a shock absorber, which is secured by two reinforced parts. Impact protection is provided by rubber buffers on the trailer frame. The axle is connected to the frame by longitudinal reaction rods. To ensure stability, a transverse rod is used, which is attached with a thread.

The frame is an element that is necessary to install the platform and suspension. A tug is welded onto it, complementing the ball hitch. Electrical wiring is located along the frame. There are support posts on the front and back of the part that serve to block the suspension.

Operating a trailer with a damaged or deformed frame is prohibited.

Load correctly

In order to drive safely, you should know the rules for placing cargo in the tow hitch.

The load must be distributed evenly over the entire area. When the dimensions are large, it needs to be distributed between the axles or strictly above the axle (if the car has one axle).

Indeed, if the load is incorrectly installed on the front of the trailer, as a result of pressure on the rear of the car, the front wheels may partially lose traction with the road, and, conversely, when the load is shifted to the rear, the rear wheels of the car lose traction with the road surface.

Therefore, to avoid an emergency on the road, resorting to the laws of physics, the load must be secured strictly in the center of the trailer, thereby increasing the control of the vehicle.

Selecting and purchasing a passenger trailer

Loading platform

The body is made of sheet steel, the platform is attached to the frame through beams with bolts and washers. The body floor is covered with rubber mats with a corrugated surface. The tailgate in the first series of MMZ-81021 was made in the form of a blank wall, later it was modified - a folding element appeared. Fixation and tension of the awning to the sides is provided by linen rope.

Trailer MMZ-81021 with awning

Device Features

Finally, let’s look at a few nuances that relate to the design and design of a trailer from MMZ.

The following points can be highlighted here:

• The frame is welded and includes a pair of longitudinal beams with a trapezoidal profile and 3 traverses;
• The total weight of the frame is about 27 kilograms in the classic version. But when repairs and modifications are carried out, the parameters may change;
• The coupling head has a conventional locking mechanism with an overrun brake and an additional safety chain;
• The body is made of sheet steel, the sides are welded;
• The body is connected to the frame with bolts;
• There are wheel compartments and a rubber-based floor cap;
• The sockets necessary for installing the arc under the awning are provided;
• Rear and front collapsible sides appeared after 1986;
• Corrosion protection was achieved using mastics;
• It was only in the early 90s that galvanizing began to be used;
• The awning was made on the basis of tarpaulin fabric and eyelets were installed in it;
• The trailer was equipped with 4 arches;
• Support posts are mounted on the cross member and allow you to block the springs;
• The chassis is made of an all-metal axle with earrings for mounting the suspension and places for mounting wheel-type bearings;
• The suspension is independent and mounted in the middle of the frame. Includes a pair of shock absorbers in springs, a pair of bump stops, conical buffers, a pair of longitudinal bars and one transverse one.

That's actually all I wanted to tell you about MMZ. In fact, the Mytishchi plant became the starting point for MMZ trailers, as they were then produced by many other enterprises. According to some, production was established at 800 factories. Whether this is true or not, I cannot say for sure.

Thank you all for your attention! Be sure to subscribe, leave reviews and invite your friends to join us!

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The main technical data are presented in the table.

The MMZ-81021 trailer, produced at the end of the 20th century, despite some design flaws, is still used by many motorists today. If you follow the operating rules, regular inspection and tightening of connections, this design can serve for a long time.

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A little history

The author or creator of such a trailer is the Mytishchi Machine-Building Plant. Hence the name MMZ. This enterprise is an integral component of the association, which is widely known as Metrovagonmash. Even during the times of the Union, the plant produced an extensive range of products, among which there was a place for passenger trailers.

MMZ began producing trailers for passenger cars back in 1972, which was far away for many of you. This was due to the fact that the AvtoVAZ company actively began to fill the domestic market with its cars. You may be surprised, but today there are about 200 thousand still serviceable trailers produced by the Mytishchi plant. With proper storage and preservation, serious results can be achieved. Although MMZ are mostly in demand among those who are interested in buying and converting trailers.

It cannot be said that these trailed vehicles have an ideal body, unique technical characteristics or other undeniable advantages. No. It's just a good trailer of high quality, which was in its time. This allowed them to survive to this day.

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Recovery

Repairing an MMZ trailer can be done as follows (the original model was practically coming apart at the seams):

1. Resuscitation begins with careful straightening of the body and sealing all cracks by welding. Next, the diagonals are checked, the sides are pulled together with soft rolled wire and the corners are further strengthened. A couple more amplifiers are welded onto the bottom part. This operation is due to the fact that in the standard version the bottom is equipped with only one amplifier, which is not enough for full operation. As a result, the metal breaks and the bottom simply falls through.
2. You can use improvised means to weld a new body bottom as an additional layer on top of the main element. Several pieces of iron 3 mm thick are quite suitable for this purpose. To begin with, the segments are welded together and then with the main coating. For reliability, the entire structure is fixed with bolts and press washers.
3. We install reinforced springs.

After restoration, the MMZ-81024 trailer was subjected to increased loads (transportation of cement, sand, crushed stone). After 4 months of use - no complaints, even compared to the new model.