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Saving General Shinseki:

On the future of wheeled armor

by Lutz Unterseher
February 2004
A PDA Guest Publication
Studiengruppe Alternative Sicherheitspolitik
Study Group on Alternative Security Policy
Berlin, DE

In the course of the recent war against Iraq and in its aftermath, it has become clear that the mix of U.S. Army ground vehicles for combat-related tasks is unbalanced and even inadequate.

Trivial insight1

The Abrams Main Battle Tank (MBT) has had a relatively good show. Due to its considerable frontal armor protection it has been able to effectively spearhead many tactical maneuvers. But it has weaknesses; a vulnerability to RPG fire from the rear and, more importantly, serious shortcomings in operational and strategic mobility, because this exceptionally heavy vehicle is driven by a very thirsty gas turbine.

The Bradley Mechanized Infantry Combat Vehicle (MICV) appears to have better protection and stamina than predicted by its critics. Nevertheless, it is a less well-protected vehicle than the Abrams, and its survivial in battle is dependent on very close co-operation with the MBT, which almost always has to take the lead in combined-arms operations. Even under ideal conditions of cooperation with and protection by heavy tanks, it is quite risky to ride on a Bradley. If this MICV is penetrated by fire, too many lives are endangered. Its 3+6 complement puts "too many eggs in the basket."

"Stryker" brigades, part of former Army Chief Eric K. Shinseki's interim force, were not ready to be employed in the conflict. They would have been considered inadequate in any case. The example of the U.S. Marines operating similar equiment (the wheeled LAV III) has demonstrated that the relatively bulky, lightly armored vehicles can not be used successfully if the going gets somewhat tougher (Hilmes 2003, p. 27). The Marines appear to have instead relied on the combination of MBT's and tracked personnel carriers with considerable add-on armor (AAVs).

The problems with multi-wheeled armored vehicles extend to the future envisoned by General Shinseki. An increasing number of experts on both sides of the Atlantic doubt the feasibility of the Army's master plan, according to which, by the end of this decade, the function of heavy, tracked armor could be taken over by a family of relatively light wheeled vehicles (system weight not much over 20 tons.) Further more, few technologists are convinced that, even in 15 years, it will be possible to create such a new family and provide it with (armor) protection equivalent to what gives today's heavy elements their central tactical role.

There are many skeptics when it comes to providing the new class of vehicles with "electric" or improved reactive armor. Similarly, there are severe doubts about active kinds of protection which attempt to intercept incoming missiles in a soft- or hard-kill mode. Critical arguments are that advanced reactive or active protection is quite expensive, relatively easy to saturate with multiple hits (machine cannon!) and hence not cost-effective (Hilmes 1999, pp.154-163.) A system enhancing situational awareness by integrating all available sensor information would be nice to have, but cannot serve as a substitute for solid armor protection. In the final analysis, heavier multi-layered armor developed since the 1970s is indispensible.

A soft skin vulnerability is evident with the HMMWV (Hummer), a vehicle originally intened for liason purposes that is now extensively used for patrol missions in (semi-) hostile territory. This vehicle's survivability is a function of its agility and relative compactness. It would be greatly enhanced, however, if there was at least a modicum of armor protection (especially against mines and small arms, which represent the bulk of weapons in modern times.) Add-on armor may not be sufficient and the Swiss and Danish examples of protected HMMWVs are not fully convincing. The vehicle has become clumsier and still lacks mine protection. The U.S Marines' experimental armored reconnaissance car (Shadow) may be a better development for all kinds of light forces applications. The Shadow weighs about the same as the HMMWV (up to 5 metric tons), has integral armor and a (German-designed) diesel-electric drive.

Saving an idea

It is, of course, not General Shinseki who needs to be saved, but the essence of his vision. Would it not be appealing to have a ground-mobile force whose armored core relies on just one basic platform that greatly enhances tactical co-ordination along with logistical support and which, as a wheeled system of considerable survivability, moves faster over longer distances than heavy, tracked elements, and lends itself to relatively easy strategic transport?

The fact that the first, very optimistic, attempt to reach such a solution has failed, or is about to fail, should not discourage other similarly directed approaches. It is perfectly conceivable that the essence of General Shinseki's vision can be saved if.

  • the envisaged restriction on the system's weight is lifted up to a ceiling that still permits the use of wheeled running gear and,
  • a holistic view of the vehicle's tactical and organizational context serves as basis for a fresh design and the systematic selection of adequate modern (but not over-sophisticated) technologies.

On the question of weight and mobility: A future wheeled combat system weighing about 50% more than the one originally envisioned by the U.S. Army would still weigh only half as much as an Abrams. Its strategic mobility would be less than that of lighter wheeled systems, but still much greater than an MBT. As for operational mobility, which is particularly important for peacemaking and peace support, there is almost no loss in comparison with lighter wheeled armor.

The increase in weight substantially facilitates the designer's task of finding a viable solution for the vehicle's basic (armor) protection. At the same time, it hampers the vehicle's tactical mobility (Ogorkiewicz, pp. 9-11.) Therefore the designer has to pay special attention to preventing the system's ground pressure from becoming unacceptably high. This calls for the utilization of modern technologies to optimize automotive performance, principally by fine-tuning the traction of each wheel and making use of adjustable tire pressure. If this approach does not suffice, perhaps the system's weight can be varied with terrain conditions (modular armor) or, more radically, the designer can aim for a different division of labor using lighter, agile elements (Shadow class) for a set of tasks over soft ground.

On the question of tactical role and adequate design: Commanding a battalion with 58 MBTs or MICVs (4 companies with 14 each, plus 2 for leader and deputy) constitutes quite a challenge. There is widespread agreement that the standard tactical entity should not be any larger. Since practically all modern war scenarios require that tanks and armored infantry carriers act closely together, the two different elements have to be integrated organizationally. If this is done by simply adding companies from the complementary arm on to a battalion the resulting force would be far too clumsy. Rather, it has to be done about by routinely mixing, and re-mixing, elements of armor and mechanized infantry within the scope of a battalion. Re-mixing is often necessary, because in the course of a dynamically evolving encounter, the happy mix of yesterday may suddenly become an unhappy one. Because of such frequent reshuffling, human interaction and bonding, necessary for flexible co-operation, may suffer with serious consequences in and among tactical units (Simpkin, pp. 87-100.)

Why not take Shinseki's idea of a family of vehicles based on a single platform and instead create a "hybrid" tank which incorporates two key elements, namely armor and infantry, in the same vehicle? There would be no more unhappy mixes, since reshuffling would no longer be required. Besides, there would no longer be a discrepancy in armor protection between the heavy tank and the lighter MICV, that has tied the former to the latter, depriving it of tactical options. And, of course, there will be considerable logistical advantage in such a one-platform solution.

However, there are design strings attached. The idea of a hybrid tank can, in this context, only be turned into a viable solution, if two caveats are obeyed:

  • The main armament (anti-tank/helicopter, multi-purpose) should only weigh a small fraction of what modern tanks are equipped with. Otherwise, it will not be possible to provide enough armor for the protection of a wheeled vehicle which has particular weight restrictions. The solution to this problem lies not only in the aplication of alternative technologies, but also in holistic insight. There has been an increase in the effectiveness of indirect fire, networked with frontline units, that greatly reduces the requirement for MBTs to deal with tank-like targets over longer distances. This, combined with the fact that all vehicles in the battalion do have the same type of "main armament," allows for a reduced volume of fire by the individual vehicle.
  • Special precautions have to be taken to better protect the mounted infantry. The fact that the hybrid system may get involved in duels with tanks could endanger the lives of the infantry if they don't dismount in time. At the system level, this problem can be solved, by not putting too many "eggs in the basket." The permanent crew should be reduced to 2 and the infantry to 4. This formula of 2+4 compares with 4 in the Abrams and 3+6 in the Bradley.

Designing SAM2


  • For obvious reasons the vehicle should be compact, but should have enough inside space for a layered, voluminous armor. To reconcile these contrary demands, all vital sub-components -- the human complement, engine, transmission, fuel storage, steering gear, and armament including ammunition -- should be as small as tactically acceptable and technically possibe. There should also be stringent weight restrictions on all non-armor parts.
  • In order to minimize essential armor needs, and to facilitate communication, the human complement should sit low and at the same level in a specially protected, undivided capsule (the turret is unmanned and without a basket.) All outside elements not directly required for protection of crew and mounted infantry would get lighter armor.
  • Tactical mobility, as argued, requires an especially ingenious design effort. Other than the option of variable combat weight through modular armor (which could be risky), there are other features worth integrating into the design. These include turning on the spot, variable ground clearance and tire pressure, as well as the fine-tuning of traction.
  • Modern engine technology should not be exploited to provide drastically higher acceleration rates, but rather be used to produce more compact and less thirsty engines. Otherwise, it will be impossible to reach the goal of having a well-protected, lighter, and more compact vehicle. (The ability to better accelerate, as a result of a high power-to-weight ratio, is not a sufficient substitute for armor protection and compactness of a combat vehicle.)

The infantry in the "hybrid" would give the battalion a dismounted force nearly as strong as an infantry-heavy mix consisting of 3 companies with Bradley and 1 with Abrams. If, as critics say, 4 infantry men per system are not enough to form a viable tactical entity, there can be a close teaming of vehicles (two pairs per platoon.)

At the individual system level, the reduction of the complement has the advantage of supporting a compact design which enhances its survivability by minimizing its likelihood of getting hit and by having more armor weight per surface area.

The notion that high-tech components are capable of solving all design dilemmas, should be rejected and a high degree of selectivity should be the rule in choosing system sub-components. In some areas advanced technology appears to be indispensible especially with respect to the vehicle's armament (including missile guidance) and to the observation and the sensor data processing comples.

To complicate matters further, at least some built-in redundancy (most importantly with regards to the sensors, but also with regards to propulsion and power train) is needed to enhance the system's survivability. This requirement may keep the designer from rendering the system "over-compact." In any case it constitutes a considerable challenge.


Name SAM ("Sammy" among friends)
Function Dual (mech. infantry / LOS fire)
Complement, number 2+4
Weight (combat loaded)
   -without skirts and side-armor panels (kg) 27,500
   -with skirts and side-armor panels (kg) 32,500
Length (m) 5.75
   -without add-on armor (m) 2.85
   -with add-on armor (m) 3.15
Height (normal ground clearance)
   -overall - to mast top, extended (m) 3.00
   -to turret roof (m) 2.25
   -to hull top (m) 1.90
Ground clearance, variable
   -normal/up/down (m) 0.40/0.50/0.30


  • on armored turntable/unmanned turret: 10 standardized, individually (up/down) trainable launchers/containers (elevation: 40° / depression: 10°) with LOSAT (guided kinetic-energy missiles anti-armor/rotorcraft, 1 per container) or unguided artillery rockets (105 mm, 4 per container) or light, short-range, short-barreled mortars for smoke and fragmentation grenades (60 mm/ 9 pairs per container) or a mix of these; reloading through exchange of containers;,
  • on telescopic observation mast: 2 machine guns (7,62 mm).
Engines 2 Diesels / High Power Density
Maximum gross output 2X300 kW
Power transmission 2 generators & 8 electric motors
Producer(s), engines/transmission MTU/Magnemotors
Running gear:
Wheels, number X driven 8X8
   -frontal wheel pair conventional
   -all wheels skid-steering
   -size 18X22
   -pressure variable
Suspension independent, trailing arm
Springs hydro-pneumatic
Wheel travel
   -bump(m) 0.20
   -rebound(m) 0.20
The second wheel pair can be lifted
to make road marches more economial
Automotive performance
Gross kW/hp per ton (maximum weight) 18,5/25
Maximum road speed (km/h) 100
Range on roads (km) 1000


Vehicle's distinguishing features:

Very compact, low silhouette, but high axis of observation thanks to (lightly armored) telescopic mast in the middle of the unmanned turret. Relatively large distance between first and second wheel pair, smaller between the other ones. Forward two thirds of the hull: wedge-shaped; rear third: box-like. V-shaped bottom and special armor to enhance mine protection. Skirts extending over the wheel pairs 2, 3 and 4. Add-on armor to protect the rearward "box". Considerable space for layered armor in front of the permanent crew.

One set of engine/generator on each side - in the armored space above the third and fourth wheel pair (redundancy!). Weight-saving through the combination of compact and economical HPD (High Power Density) engines with an electric (non-mechanical) transmission, which is also good for the fine-tuning of traction. In addition: weight-saving through the reduction of the steering gear (only for the front wheels.).

Skid-steering for turning on the spot (like a tracked vehicle.). Fuel storage in lightly protected tanks attached to the multi-layered ramp in the rear, and in parts of the bottom. Redundant, all-weather capable means of observation and target acquisition at the telescopic mast and the crew stations. Unmanned turret over the rear third with its armored turntable serving as additional protection against top attack.

Shinseki All-purpose Memorial tank - elevation

Shinseki All-purpose Memorial tank in elevation overlay of Abrams M-1 tank

Summary description of the SAM combat vehicle:

Considerable, versatile firepower (kinetic energy and fragmentation) without the weight penalty of a main gun system and its special loading machinery. Slightly more than half the weight of an Abrams - and about 60% of the surface area. Designed to have fewer "bullet traps" than the tank. Accordingly a high degree of crew protection. Better strategic mobility. Superior operational mobility -- good for long and swift marches. Acceptable tactical mobility.


1. This critical review of U.S. Army equipment could have been written before the invastion of Iraq and a version actually was, as an armchair evaluation (Unterseher 2000.) It is unfortunate that full scale wars are required in order to arrive at conclusions that are not much more than trivial.

2. SAM stands for Shinseki All-purpose Memorial tank. Its design occasionally borders on squaring the circle.


Hilmes, Rolf. "Kampfpanzer: Technologie heute und morgen," Bonn: Report, 1999.

----------------. "Panzereinsätze im zweiten Golf-Krieg," Soldat und Technik, November 2003, pp. 25-28.

Ogorkiewicz, Richard M. "Wheels or tracks?: Tracked & Wheeled Light Armoured Vehicles," International Defense Review editorial supplement to Vol. 19 (1986), pp.9-16.

Simpkin, Richard E. Mechanized Infantry, Oxford: Brassey's, 1980.

Unterseher, Lutz. "Wheels or tracks? On the "Lightness of Military Expeditions," PDA Briefing Memo #16, July 2000.

---------------------. "Gepanzerte Fahrzeuge - Wohin die Reise?," Soldat und Technik, November 2003, pp. 10-13.

Citation: Lutz Unterseher, Saving General Shinseki: on the future of wheeled armor, Project on Defense Alternatives Guest Publication. Cambridge, MA: Commonwealth Institute, February 2004.

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