What is a portal bridge
The idea itself of placing the beam above the wheel axle has been incubated since 1946. German engineer Albert Friedrich used a similar scheme on Unimog SUVs. There is only one way to increase the ground clearance of a car with continuous axles - installing portal axles. On UAZ, such a scheme began to be used only in the late 60s, when the Soviet designer Mirzoev, the author of gear axles on the UAZ 469, received a record ground clearance at that time - 378 mm.
At that time, the maximum ground clearance was considered to be 250 mm. Portal axles could not be used on every European SUV; it was possible to install only on a number of models:
- Unimog;
- UAZ;
- Volvo C303;
- Pinzgauer.
From the diagram presented above, it is clear that the portal bridge is a continuous beam and final wheel drives. Due to the gearboxes, the axle can be raised to a certain height relative to the wheel axis, plus, the dimensions of the main gear are significantly reduced, which makes it possible to reduce the dimensions of the main gearbox housing.
Advantages of portals for SUVs
The very name of portal bridges comes from the definition - in mechanical engineering a portal is called a spatial load-bearing structure. Such bridges are used only in military equipment and on fierce SUVs, where, more than anywhere else, an increase in ground clearance comes in handy. Also, such axles help reduce the load on the clutch, reduction gearbox, transfer case and gearbox if wheels of a larger diameter are installed compared to stock ones.
As a result, we get a whole list of advantages valuable for off-road vehicles:
- the ability to obtain increased ground clearance, which can easily be varied by installing wheels of different diameters;
- the lower gear ratio of the portal axles on the UAZ 469, on the UAZ Hunter allows for greater traction force, which is also important when driving in conditions of impassable mud and loose snow;
- the smaller the number of teeth in the main gear, the more reliable the gearbox, and on portal bridges the teeth of the main pair are also larger, which means increased reliability of such gearboxes.
There are also some disadvantages. For example, the maximum speed will be reduced by 20 percent, depending on the gear ratio of the main pair. But this minus is not at all fatal for cars designed to operate in total off-road conditions. The installation of portal axles has virtually no effect on handling; according to engineering calculations, it worsens by no more than 3%, but the dynamics of acceleration drops by 35-40% compared to a standard drive axle.
Portal bridges for UAZ
In nature, there are several models of portal bridges, including domestic ones. Let's start with them, perhaps. The most budget-friendly way to install a portal axle on an SUV is to install and fit a used axle yourself. Depending on the car model, you can use a military portal bridge from UAZ. The downside is obvious - there is a lot of work to be done, and the condition of the three gearboxes that are installed in the beam is unknown. You can check the performance and find out the degree of wear only by opening the gearbox.
For sale there are both new axles from UAZ 3151-03 and used ones. They are slower than standard bridges from civilian UAZs, but also have higher torque. How much the game is worth the candle is up to everyone to decide individually, since the increase in ground clearance is 80 mm - 40 mm is obtained by reducing the size of the gearbox housing and another 40 by shifting the beam axis relative to the wheel axis.
Axles with final drives T 40 on UAZ
The UAZ Patriot SUV is designed to overcome various off-road conditions. But when the goal arises of overcoming not only off-road conditions, but also impassable routes and hilly areas, then this necessarily requires the installation of portal bridges. These devices have been known for a long time, but they have been gaining popularity recently, when candidates for testing portal bridges appeared. One of these contenders is the UAZ Patriot SUV; therefore, today we will pay attention to the purpose of the products, features and some models.
Portal bridges got their start back during the war, when designers were tasked with increasing the cross-country ability of vehicles. The task was not easy, but doable. Portal axles were invented, which involve placing the bridge axle higher than the wheel axle. This phenomenon was achieved by installing a special gearbox with gears into the bridge. Portal - they began to be called because of the spatial supporting structure.
This design is used among fans of overcoming Offroad trails, which are becoming more and more popular every year. And now not only outdated UAZ Bukhanka or Niva, but also modern UAZ Patriot, Chevrolet Niva, etc. take part in the races. Thanks to this design, the UAZ Patriot SUV increases ground clearance, which is the main function of such units. Thanks to the use of several gearboxes in the design, the load on the transmission system is reduced without causing rapid wear.
If you are reading this material, it means that the idea has appeared in your head to tune your UAZ Patriot SUV by installing a portal unit. What are the pros and cons of replacing standard axles with portal axles?
- First of all, the presence of a gearbox with gears will reduce the speed of the vehicle, to about 20%.
- Now the SUV will accelerate three times longer, thanks to the same gearbox design.
- Reduced vehicle controllability.
But along with the minuses, we also get inversely proportional pluses:
- Improved geometric characteristics, which means better balance when driving on plains, hillocks, etc.
- Increased traction characteristics.
But if we consider that the main task of the designers was to ensure high cross-country ability of the car, without focusing on speed, then we can say that they coped with the task. Therefore, if you are going to the mountains in a UAZ Patriot SUV, then it is impossible to do without such devices.
In fact, only those motorists who are not afraid to risk their lives or their car install portal bridges.
Product Features
The installation of portal units not only improves cross-country ability, but also increases ground clearance, which is very important for overcoming various aggressive obstacles. By raising the axles above the ground, it becomes possible to install wheels of larger diameter, which is also important for overcoming obstacles on the road.
Thanks to the presence of a gearbox in the axle, transmission unloading is ensured. Participation in competitions to overcome obstacles will allow you to achieve victorious results. After all, competitors with conventional bridges have no chance of overcoming aggressive off-road conditions. In everyday life, the presence of such a device is not very popular, unless you live in a steppe or forest-steppe zone, where every day you have to drive your UAZ Patriot SUV through forests and hills. Thus, we can say that portal bridges are necessary when you are tired of suffering from daily slipping in fords.
Let's look at some options for portal units for the UAZ Patriot SUV.
Military bridges
During the war, a popular car was the UAZ Bukhanka SUV, which actually received its first military version. Today, more and more often, owners of the UAZ Patriot SUV are resorting to installing such products at their own expense. Military bridges are characterized by relatively low cost, simplicity of design and, most importantly, strength. After all, in wartime, the main thing was that the product did not fall apart while moving. Therefore, military products are still popular to this day, as they are quite reliable and practical.
But here a new snag appears, because it is almost impossible to get military bridges these days. New military units have not been produced by factories for a long time, so you can find them among advertisements. Of course, purchasing a device that has already been used is extremely risky, because there are no guarantees that military products will last a long time. Unless you take into account the fact that they were made to perfection.
If military bridges fall into disrepair, then it is not possible to repair them now. Therefore, if they fail, you will simply need to install a more modern version. Therefore, it’s up to you to decide whether you should strive to install military structures on the UAZ Patriot, but in the end you will still have to settle on modern, as they are called, collective farm options.
Bridges from the UAZ Bars SUV
The portal axles from the Bars SUV to the UAZ Patriot are military analogues, but only with a widened track. The track of the Bars design is expanded by 155 mm from its military counterparts, and is also calculated for spring types of suspensions.
Exterior view of a car with Bars products
If there is a need to install portal units, then it is recommended to opt not for military ones, but for Bars designs, which perform well when driving on aggressive off-road conditions. To install “Bars” instead of the standard one, you will need to replace the cardan, and the mounting of the shock absorbers will also change. With the Bars bridge you can install wheels up to size 37, while the standard product has 29.5 inch tires.
Of course, the operation of the popular Russian SUV UAZ Patriot on longitudinal Bars bridges on city roads is not intended, since we have already said that the speed characteristics of the car are significantly reduced. But driving outside the city, on training grounds, in the steppe or mountains - all this is possible for an SUV with longitudinal Bars axles.
Of course, military bridges and Bars are not the only models for an SUV; foreign analogues are also known, such as:
- Pinzgauer, made in Germany;
- Unimogs, which are popular among Nivas;
- Tibus, the most popular products for all types of off-road vehicles.
The advantage of the latter option is that by installing such a unit, the speed of the car practically does not decrease. In addition, the ABS system, if equipped on Patrick, remains operational. Therefore, if you have the funds, you can install a foreign analogue, but is it worth it? Bars bridges, unlike military ones, can be found in UAZ service centers. Installation of products is carried out independently if you have a hole in the garage and a set of tools.
To summarize, it should be noted that Bars portal bridges are the most popular units that show excellent results in competitions.
1 Comment
Maksim
Hello everyone, yes, the portal bridge has a complex mechanism, I was looking for information for a replacement on the UAZ, I visited many resources, but everywhere they say differently and you don’t know who to believe, but I found more reliable information here swapmotor.ru
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Features of portal bridge 3151-03
Such an axle is much more reliable than the standard one, since they have larger main gear teeth and the torque is distributed more evenly between three gearboxes, and does not fall on one, as in the Standard UAZ. What's bad is that a military bridge is heavier, has more parts and is much more difficult to repair. You also need to take into account that fuel consumption will be slightly higher. For example, a UAZ Patriot with portal axles will ask for two liters of gasoline more than a regular Patriot with civilian axles. There is a modification of such a bridge, 3159 Bars, in which the track has become wider and is 1600 mm with the same ground clearance of 80 mm. The hubs on both axles require the installation of 15-inch discs.
Branded final drives will not be affordable for everyone, since without installation a hardware kit for, say, Tibus will cost a million rubles.
Therefore, the only option for installing portals on a UAZ is to purchase used or new military bridges from model 3151-03. The price of such bridges ranges from 60-70 thousand assembled. Happy travels to everyone!
Front final drive T-40
This mechanism consists of a single-stage mechanical gearbox with straight teeth. Its main task is to reduce the rotation speed and increase the torque of the tractor wheel apron.
The final drive gears of the T-40 and T-40 AM tractors have different gear ratios and cannot be interchangeable.
Scheme of the front side T-40
As we said above, the final drive of the T-40 tractor consists of a wheel gearbox, based on this, we need to consider its diagram
Each detail has a detailed explanation; the picture enlarges when clicked.
