Singapore has the largest fleet of French Giat Industries (previously Mechanique Creusot-Loire) built AMX-13 light tanks in the world and for many years, Singapore Technologies Automotive Ltd (STA) (previously Singapore Automotive Engineering) has been overhauling these and other tracked and wheeled armoured vehicles for the Singapore Armed Forces.

More recently, Singapore Technologies Automotive Ltd has developed a complete chassis refurbishment programme for the AMX-13 with the first production vehicles handed over to the Singapore Armed Forces in June 1988 under the designation of the AMX-13 SM1. It is understood that most of the Singapore fleet of 350 AMX-13 light tanks has been upgraded to the AMX-13 SM1 configuration.

The main area of improvement is in the chassis which has been given a total automotive refit with a new Detroit Diesel 6V-53T engine, a new ZF 5WG-180 fully automatic transmission, a new electrical system and a hydropneumatic suspension system. These improvements not only make the AMX-13 SM1 more reliable but also increase the operational range of the vehicle, giving a higher speed, better acceleration and improved cross-country mobility.

Singapore Technologies Automotive Ltd is now offering this retrofit kit for other users of the AMX-13.

Singapore has a requirement for a new light tank and available details of this are given in the Singapore Armed Forces new light tank entry.

The original petrol engine has been replaced by a more fuel efficient water-cooled, turbocharged Detroit Diesel Model 6V-53T which develops 290 bhp at 2,800 rpm. This can be replaced in 50 minutes.

The engine cooling system for the upgraded AMX-13 SM1 light tank has been designed, developed and produced by the UK company Gallay.

The AMX-13 SM1 cooling system consists of three air-cooled heat exchangers which are mounted in series. Air passes from front to back through the assembly, cooling in turn the oil from the steering brakes and differential, the engine cooling water and automatic transmission fluid.

The engine is coupled to a ZF 5WG-180 fully automatic transmission with five forward and two reverse gears. This is controlled by an Electrical Control Unit (ECU) which is programmed to protect against unsafe shifts. In case of an electrical failure there is a mechanical fallback.

A new electrical system has been fitted which is more reliable and is easier to maintain and repair. This is based on four 12 V batteries connected both in series and in parallel. If a single battery fails, the others can still supply power. In addition there is a new 28 V 160 A fully suppressed alternator. This is more reliable than the older dynamo and is easier to maintain.

A new electrical slip-ring has been fitted, as have new instruments for the driver. A new radio harness is sealed in shrinkable polyolefin tubing which provides protection against oil, fuel and moisture. It is also heat retardant and in the event of fire does not give off toxic fumes. All sections can be quickly disconnected and replaced for repairs in the field.

The original torsion bar suspension has been replaced by a new hydropneumatic suspension system which increases total wheel travel, absorbs greater shock loads and permits greater mobility over rough terrain.

The danger of shredding tracks is reduced as the suspension system maintains a more consistent tension on the track. The pressure in each unit strut can be individually adjusted.

The AMX-13 SM1 retains the 75 mm main armament and 7.62 mm coaxial machine gun of the original AMX-13 but an additional 7.62 mm machine gun is pintle mounted on the forward part of the turret and this can be used by the commander or gunner. A bank of two electrically operated grenade launchers is mounted either side of the turret firing forwards.

• STA VCI Upgrade

In February 1994, Singapore Technologies Automotive Ltd revealed that as a private venture it had completed the prototype of an AMX VCI infantry fighting vehicle (fully covered in the Armoured personnel carriers (tracked) section) fitted with the same power pack and suspension improvements as the AMX-13 SM1 light tank.

As Singapore does not operate any AMX VCI infantry fighting vehicles, this upgrade is aimed specifically at the export market.

In addition, the upgraded AMX VCI was fitted with a new turret designed by Chartered Industries of Singapore (CIS) fitted with a CIS 40 mm 40 AGL grenade launcher and a CIS 12.7 mm machine gun. This is also fitted to upgraded M113 series APCs and details are given in the Armoured personnel carriers (tracked) section under Singapore.

This upgrade programme is believed to have been completed. In service with the Singapore Armed Forces (350). It is believed that a number of export AMX-13 light tanks have been upgraded to the SM1 standard.