Portal bridges: what's the joke here? Comparative review of “portals”

Unit for UAZ from MTZ

What can hurt a driver more than an SUV buried in sticky clay? Agree, this is a blow to the pride of any owner of a car with all-wheel drive. And the car owner, after getting into such an unpleasant situation, is ready to shell out significant funds to improve the characteristics of his off-road vehicle.

The use of the UAZ Patriot shows that this car can, at least with a stretch, be called a cross-country vehicle. To pass serious off-road tests, many owners try to make some changes to its design. Particular attention is paid to the front axle of the UAZ.

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Comments 57

We made similar bridges for the swamp vehicle www.drive2.ru/b/1726213/

The wheels are similar to Escudian ones. they are ventilated and have a UAZ drill, only the center is 108mm and the pin is thinner.

Why not buy a tractor right away in addition to the UAZ. With such modifications, it will really lose speed and a lot. Of course, the traction will be a wagon and a small cart. But there will be no coasting as such. It will be, as they wrote below, keep the gas going. .We have a new MTZ 82.1 on the robot, it is all-wheel drive. I remember how I went out to work on the first day, drove in and threw the cardan off the front end because the roll-up is very bad and noisy. Without a cardan, the flight is normal, but on a simple MTZ 80 without a front end the roll-up is better and quieter For me, the UAZ is already a worthy rogue, and these alterations will turn it into a tractor and that’s it.

You've already started doing it

Why, I counted the number of teeth on the tractor driven gear of the on-board vehicle and the axle shaft of the UAZ and the number does not coincide: there are 10 and there are 12.

do not confuse, the rear and front gears are different

Why, I counted the number of teeth on the tractor driven gear of the on-board vehicle and the axle shaft of the UAZ and the number does not coincide: there are 10 and there are 12.

and on the front axle the front axle shaft is not short, the gears will hook into the final drive if the steering knuckles are left in the military

the rear axle has the same gear as the front axle, why make rear axle shafts?

Didn't the regular spicers remain by chance?

Of course, this is all good and the ground clearance is high and the film is entertaining.

It’s a great solution to hang another gearbox on the final drive. Hence the question: does anyone think about the increased load on the king pin? Weight and kinematics have changed! Do you understand the stress they are under? Or are they made of nano shells? )))))

Is it possible that our Kulibins don’t pay attention to little things?

Who needs your talk about cinema? The car is moving, the wheels are rowing...

Of course, this is all good and the ground clearance is high and the film is entertaining.

It’s a great solution to hang another gearbox on the final drive. Hence the question: does anyone think about the increased load on the king pin? Weight and kinematics have changed! Do you understand the stress they are under? Or are they made of nano shells? )))))

Is it possible that our Kulibins don’t pay attention to little things?

there is one gearbox. The native military man is removed

By the way, the warriors voin4x4.clan.su/index/uaz…i_grazhdanskie_mosty/0-14, from this year, for gear axles (military), instead of standard onboard ones, they began to make wheel reducers with helical gears, with different reductions, as for tourism, so much for the trophy. You can even go on a long expedition with them. The gears are larger in modulus or not inferior to T-40 and thicker. In front of me, they took a serial one from the T-40 and hit it with theirs, there is no trace of it, there is a dent from the T-40, they say they are now doing it with cementation, they give a guarantee. But we took the assembled portal bridges.

In terms of? In the contacts on their website, there is a representative in your city, Moscow, you can check.

It’s just that there is such a famous Barnaul scammer Kraftov, who has also been sculpting wheel gearboxes for a long time. The idea is not bad, but the workmanship is below par. That’s why I asked if these were his next creations.

Well, that's what I thought. It was “voit4x4”, which means it became “voin4x4”. Very creative. :))

Well, call the representatives personally and ask about quality. Smear all the masters through third ears. It would be so bad if no one signed up for them. For example, if you are sent everywhere, you go to them, they cope with any task. For example, we have a hydraulic cylinder from them, assembled using imported components, for only 25,000 rubles together with rods, stroke 25cm. And the imported one doesn’t say how much it costs.

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?

1. First of all, the presence of a gearbox with gears will reduce the speed of the vehicle, to about 20%.
2. Now the SUV will accelerate three times longer, thanks to the same gearbox design.
3. Reduced vehicle controllability.

But along with the minuses, we also get inversely proportional pluses:

1. Improved geometric characteristics, which means better balance when driving on plains, hillocks, etc.
2. 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.

DIY gearbox repair

Repairing a final drive is a rather complicated procedure, but if you have certain skills, it can be done independently. First you need to remove the side gear housing itself.

Disassembly of the final drive must be done in a vice. To disassemble the final drive, you need to unscrew the bolts holding the locking plates. Next, you should inspect each bearing for its further operation. If a major overhaul is carried out, each bearing must be replaced.

When carrying out repairs, it is imperative to fill the final drives with new oil. All parts that have chips, cracks and gouges must be replaced. The gear axle shaft must be checked for integrity. If you plan to use it harshly, it is better to install reinforced shafts. The seals also need to be inspected and the faulty seal needs to be replaced.

The final drive must be assembled using a vice. All elements of the assembly are assembled and installed in the final drive housing. The differential is put in place, the bearing caps are screwed on. This completes the gearbox repair.

Traditional Design Possibilities

The successful design of a classic SUV, which, without a doubt, is the UAZ Patriot, which became the direct successor of the UAZ 469, allows you to prepare the car for multi-purpose use. If we talk about possible settings, we need to proceed from the vehicle's use cases. Several designs of certain components and assemblies can be selected at once for further use or modernization. This approach is quite justified when it comes to the UAZ front axle.

The traditional design of the front axle is shown in photo 1. The option with a central gearbox, differential and axle shafts is well known to car owners.

This is what ensures the increased cross-country ability of a classic SUV.

All-wheel drive provides perfect control on the road

1. All-wheel drive when all 4 wheels are driven.
2. The use of a low range of gears in the transfer case. The engine's traction capability and maximum torque are perfectly realized here.
3. Inter-wheel differential locking, when torque is redistributed from a slipping wheel to a wheel that has stable contact with the ground.
4. Blocking the center differential, when, as necessary, torque is transmitted (or used in equal proportions) from the front axle to the rear axle of the UAZ. This distribution allows you to load exactly that part of the car that is capable of performing a larger amount of work.

To improve cross-country ability, you need to pay due attention to the type of tires used, equip the UAZ Patriot with special devices such as a winch, a power bumper in case the vehicle is rescued from impassable mud.

How else can you increase cross-country ability?

Do not forget that the vehicle’s cross-country ability depends not only on the drive capabilities and design features of the transmission. These characteristics are greatly influenced by such vehicle features as suspension travel, wheelbase, approach and departure angles on slopes. One of the important indicators is also the vehicle's ground clearance, or ground clearance.

Homemade portal bridge

1. Significant increase in ground clearance. May vary slightly depending on the tires installed.
2. The width of the bridge can be changed. This allows you to install tires of any size and further increase cross-country ability.
3. Some change in maximum traction compared to conventional axles, taking into account the gear ratio of the installed gear engagement in the wheel reducer.
4. Increased reliability of transmission components and parts. This is due not only to the high reliability of the spur gear, where a small number of teeth are used and there is no high rotation speed. Redistributing part of the load to the final gearbox allows you to remove possible excess torque on other elements of the transmission mechanism.

All of these features not only increase the vehicle’s off-road capability, but also increase traction. This allows you to take on additional load when transporting goods, towing a trailer or vehicle, or wading.

Known models of portal bridges

Among the most famous examples of portal bridges that can be installed on a UAZ are the following models.

Bridge UAZ - 3151-03x. An affordable option to increase ground clearance. Provides a track width of 1453 mm and ground clearance of 300 mm. The gear ratio of the wheel gearbox and final drive is 5.38 in total. One of the varieties of this design is the “Bars” bridge for the UAZ-3159, which differs from the previous model with a track increased to 1600 mm.

Volvo C-330 is an ideal to emulate

The Volvo C-330 model is also used for installation on UAZ vehicles. The use of a bridge from a real all-terrain vehicle allows you to increase ground clearance by 140 mm. The design has less weight compared to the previous one, makes it possible to increase the track to 1540 mm, and is generally highly reliable. Another significant advantage of such a bridge is the self-locking differential due to the operation of a vacuum servo drive. This type of axle is designed to work in tandem with 16-inch wheels.

The Unimog model can be called a classic. At the same time, it still shows unsurpassed characteristics. The design not only provides the opportunity to increase ground clearance by 140 mm, the safety margin of these bridges is more than enough. In terms of reliability, this is a real leader. Unimog axles can be installed either front or rear. Moreover, the front axle is 35 kg heavier. The designs allow the installation of rather large wheels on 20-inch rims.

Cargo models should not be considered. Among such installation options, we can only name a modification of the Pinzgauer bridge.

The above-mentioned designs, despite all their advantages and relative ease of replacement, have one drawback, which most people take into account. This disadvantage is the rather high cost. The model from Unimog is offered for 5 thousand. e., and the lighter Volvo C-330 can be purchased on average for 7 thousand. e.

Homemade samples

Car owners who decide to install portal axles on UAZs try to use the most affordable design of all possible - a tractor axle. In this case, it is necessary to connect the middle part of the bridge from the MTZ-82, and the final drives of the wheels - from the T-40 tractor or its analogues.

Creations of the hands of folk craftsmen

Despite its apparent simplicity, such a bridge not only has more mass, but also requires careful testing of its performance even before installation on the car. This should be done by designing a mechanical transmission to drive the bridge during testing.

The use of tractor wheel gears makes it possible to install a device for automatically pumping air into air cylinders, and the safety margin simply ensures “tractor” cross-country ability. This structure is unlikely to require repairs in the near future.

The experience of creating a portal axle with your own hands shows that such a design will provide good ground clearance of 430 mm, and the size of the tires used can reach R 36 when paired with a limited-slip differential. Of course, the car will lose some controllability and maneuverability, but it will satisfy all the expectations of its owner.

Another well-known variation of the portal bridge design is a modification that has wheel gears that can be dismantled depending on the need. After all, they are not always needed even on difficult roads; it all depends on the time of year. There is no point in wasting additional fuel on driving unnecessary mechanisms. Do not forget that the use of portal bridges still does not add comfort when driving; vibrations and noise increase somewhat.

The car's capabilities will increase if a spring suspension with a large stroke is mounted on the front axle. Reinforced springs must be installed on the rear axle. This combination will allow you to easily storm not only the deepest ruts, but also all kinds of hills and slopes. It will take a lot of effort to achieve diagonal hanging for a machine with such equipment.

When the owner of an off-road vehicle is about to start upgrading any component or unit, he must answer the question of the need for such intervention. After all, serious financial costs will be required, and significant changes will be made to the design of the car. Perhaps you should limit yourself to installing powerful off-road tires with developed lugs.

When planning to modernize the design, you should not only prepare the necessary tools, a circuit for the work and decide on the choice of device. It is also necessary to take into account possible costs. After all, replacing a bridge requires additional costs.

Portal bridges with onboard T-40.

reducers (final drive) of the front axle of the T-40 tractor (portal 125 mm) are used as wheel reducers

The cost of the set (front + rear axle) is from 150 tr . depending on the configuration. The total axle ratio is from 7.0 to 12.0.

The following axles are presented: Main gear (GP) from GAZ (Chaikovskaya) with T-40 wheel reducers, steering knuckles from T-40 - axle gear ratio (PR) 9.8. The axles are strong, on a tractor tree, the clearance is 45 cm. Traction axles on asphalt are about 70 km/h, they relieve the load on the car’s transmission, the Nivov gearbox with the RK is viable with such axles, the clutch is also unloaded. The width of the axles (at the hubs) is 185 cm, the track with discs from MTZ-82 is about 165-170 cm. The transmission brake (a brake disc on the transfer case with two calipers - two circuits, working and parking) can handle such axles quite well. The price of such bridges is from 150 thousand rubles. up to 170 tr . (depending on the presence of locks).

Bridges with GP from the BTR-80 are good (the middle part is made of aircraft-grade aluminum), light and at the same time durable. Wheel gearboxes T-40 , steering knuckles from an all-wheel drive GAZelle (open, drive on crosspieces, an example of axles is given). Bridge IF 5.16. The bridges are high-speed, the view is impressive, the wheels have disc brakes all around. We make it for the UAZ hub, R16 wheels, it is better to use tires no larger than 35″. The width of the bridges at the hubs is 160 cm (laplanders, leopards). For such bridges you need a stronger motor of 130-150 hp. with a torque of 250 Nm., gearbox with gearbox corresponding. The bridges are suitable for installation on heavy vehicles (2-3 tons). The armored personnel carrier locks as standard, the price is 200 rubles.

Another option for bridges is warriors with T-40 wheel gearboxes. IF axle 7.0 (golden mean) with a five-speed gearbox on the highway at 80-90 km/h, and off-road, they also go quite well. The bridges are good for installation on UAZ, Niva, and light frame foreign cars. Clearance on 31″ tires is 41-42 cm. UAZ hubs, wheels R16 (with disc brakes), R15 (with drum brakes), it is possible to install BTR-60 locks. The width of the axles at the hubs is 156 cm. Price without blocking is 180 rubles.

The production time for bridges is 2-3 months (depending on the type of bridges). Weight: front axle 180-200 kg. (depending on the steering knuckles), for comparison, the front axle is 165 kg, the rear axle is around 150 kg. (warrior 130 kg.).

Replacing wheelsets

Often standard wheels are not enough to overcome serious off-road conditions. When installing special rubber, the main pair is usually replaced. The characteristics of standard wheelsets are designed specifically for the use of factory tires. If you don't replace the wheelsets when switching to larger wheels, they won't last long.

After replacing the wheelsets, they must be adjusted, which consists of accurately setting the gear play and uniform tightening of the bolts. Adjustment will allow you to avoid rapid wear of parts and other problems with wheelsets.

When installing military bridges, the main thing is to be aware of why you need a car. If it was purchased exclusively for off-road use, then a military bridge is the best solution. For a car that will have to be used frequently on the highway, this is not the best choice.

If you have any questions, leave them in the comments below the article. We or our visitors will be happy to answer them