Siver: Super Cross-Country Ability Based on GAZ-66 and "Sadko"

The modified vehicle was named "Siver". It sounds like the North, where such equipment is most in demand. However, are there few places here where roads are... um, how to put it mildly? - well, you understand what I'm getting at. Instead of building them, at least some, we invent vehicles that don't need roads or almost don't need them. And our vast expanses oblige...

Amphibious all-terrain vehicles on low-pressure tires appeared. In certain cases, it is difficult to find a worthy replacement for them - in the same swamps or virgin snow, but on muddy clay ruts, on logging trails, these vehicles do not drive well. I personally became convinced of this during a trip along the "dead road" (see PP4x4 No. 12, 2011). A long time ago, a friend and I ended up in a forestry on just such an ATV. The locals' verdict was unequivocal: "You won't get far - you'll puncture all the tires." But people drive and suffer: what else can they do - standard wheeled transport no longer drives here, and tracks are a whole different story. At the "Zavod Vezdekhodnykh Mashin" near Nizhny Novgorod, in cooperation with "Spectech" LLC, they produce small batches of something greater than a GAZ-66 or "Sadko" precisely to replace amphibious ATVs in places where they can be operated, but shouldn't be.

Stilts for "Sadko"

The idea is not original: increase ground clearance and, accordingly, install huge wheels. Both of these circumstances radically affect cross-country ability. Portal reduction gears of their own design were hung on the standard drive axles. Since the gear engagement is external, three shafts are required in the mechanism - otherwise, the vehicle will drive backward instead of forward. The total gear ratio of the additional transmission is 2.06.

The sample I tested was equipped with TyRex Agro tires sized 21.3R24 (IYAV-79 of the same size, but diagonal, are also found). The outer diameter of the wheels is 1400 mm, which is 460 mm larger than the standard parameter. As a result, you can walk under the vehicle squatting - the ground clearance is 650 mm. Let me remind you: in the factory version, the "Sadko", like the GAZ-66, has a clearance of 315 mm. Of course, in addition to increasing ground clearance, the portal gears work to increase torque at the wheels, because otherwise the standard engine and transmission would not be able to spin them.

Since the chassis of the discontinued GAZ-66 and the still-living "Sadko" are practically identical, the kit of gears and wheels (plus original rear axle shafts and outer parts of the front CV joints, as well as brackets for mounting the gears) is suitable for installation on both trucks. The former (GAZ-66) is bought more actively. You wouldn't envy the driver and passenger here: no driving convenience, no comfort. A double-cab variant is also impossible, but there is a circumstance for which everything is forgiven.

The aforementioned advantage in weight distribution is not relevant here - everything is much more prosaic: such a vehicle is cheaper, since the "shishiga" (GAZ-66) is bought used, and the "Sadko" is brand new, straight from the factory conveyor. The price tags are noticeably different. True, the condition of the vehicles, to put it mildly, is also different. Before retrofitting, the GAZ-66 still needs to be brought back to life; it's much more pleasant to work on a new vehicle. Although surprises are possible here too: on the "Sadko" I rode, only the test driver was able to engage the front axle... with his foot from the rear seat. So not everything is so clear-cut. But the "Sadko" comes in the factory version with an MMZ D-245 diesel, which is much better than the gasoline ZMZ-513 engine. Often, an installation of a diesel engine on the "shishiga" is ordered along the way, so as not to experience problems due to a lack of torque on the huge wheels.

No Spare Tire Needed

However, it is not at all necessary to buy a fully retrofitted vehicle - you can install a kit of wheels and gears on your proven truck yourself, and this option appeals to many customers. It's not a UAZ, of course, the scale of the parts is somewhat different; you can't do without light mechanization. For example, a gear weighs about 80 kg, and a wheel assembly with a disk is under 200. (A spare tire, by the way, is not provided at all due to its size and weight: there is a central tire inflation system, and it's quite possible to get to the base on a flat tire - it's not so easy to destroy rubber with a multi-layer cord).

The vehicle becomes heavier - does the payload it can carry drop? That's true, but such transport is rarely used to carry serious cargo. The most in demand is not a truck with a large platform and a two-seat cab, but a hybrid with a double five-seat cab and a stubby little body in the back. The main thing is to get yourself and light expedition gear to places where neither a standard "shishiga" nor a three-axle "Ural" can reach. Such a task faces hunters (private or commercial), geological prospectors, and many others who, due to various circumstances, are forced to move through the undeveloped expanses of our country.

The standard speedometer is no good: the speed has dropped by half, so the scale is taped over

The whole point of the design is in the portal reduction gears

First-Hand Accounts

Unfortunately, I did not get a chance to truly test the driving performance of the "Siver". The surrounding lowlands had dried up, and there was no opportunity to go far. Besides, it's a long story, since the vehicle's speed is low - long hauls are not for it. We only crossed the Volga oxbow a few times without experiencing the slightest difficulty. Let's trust the words of driver Andrey Kravchenko, who claims that a standard "shishiga" would hardly have been able to get out onto the shore on its own.

Let's listen to those who have tested the vehicle more thoroughly than we did. For example, here is what Valery Lavrentyev from the town of Kotlas (southeast of the Arkhangelsk region), director of the forestry enterprise "OrbitaLesService", said: "We use the 'Siver' to deliver crews to remote forest areas. Either before logging begins or after it ends - in both cases, there are practically no roads. TREKOL is not suitable, mainly because low-pressure wheels are not adapted for driving through the forest - they are very easy to puncture. When you find yourself with a hole in a tire fifty kilometers from the base, in complete wilderness, it is simply dangerous, since there is nowhere to wait for help. The reliability of vehicles with UAZ components, which here experience completely different loads, also leaves much to be desired. Tracked vehicles are strong and passable, but transport is needed to move them from one work area to another. You have to drive on normal hard roads too, and on tracks, it's sheer torture."

Might as Well Install Navigation Lights

So we decided to try in operation a vehicle of super-high cross-country ability, and not an amphibious ATV for a narrow field of application. We chose a vehicle based on the GAZ-66: trust in the honored army truck is higher than in the relatively recently baked "Sadko". We have no complaints about the modernized transmission - it works without breakdowns. On very weak soils, the "Siver" cuts a deep rut - that's a minus. But on peat bogs and swampy soils, it drives incomparably better than the TREKOL: the tires have good grip on the ground and don't slip. We don't pay attention to snags and sharp stumps anymore. We have now ordered a third "Siver".

Technical Specifications "SIVER" 3VM-39081

These final words from Valery clearly show that the vehicle turned out well, people like it, and it is in demand.

For the "Siver", this is, of course, not off-road; the vehicle is capable of going through a much deeper rut - we simply didn't find one.