In co-operation with the Finnish Defence Force (FDF), 0y Sisu Auto Ab developed the E11T-6 x 6 HMTV to produce a vehicle combining excellent on- and off-road mobility with the ability to transport heavy payloads under extreme conditions.

The first 6x6 HMTV was shown in 1998. This was followed by the E11T-8X8HMTV.

The 6 x 6 chassis-cab has an all-terrain payload of 15.5 tonnes; the 8 x 8 an all-terrain payload of 19.7 tonnes.

Both models are entirely conventional in design and constructed using standard Sisu or third-party supplier commercial components to reduce purchase, operating and through-life costs.

A purpose-designed C-section ladder-type chassis is common to both models. Critical components, such as the electrical, fuel and pneumatic systems, are located in protected areas within the chassis rails.

Both models use a parabolic leaf-spring suspension system and all axles are Sisu units. Sisu Axles supplies axles to many third-party vehicle manufacturers.

Cummins diesel engines developing 380hp (6 x 6) or 420hp (8 x 8) provide motive power for in-service HMTVs. The 6 x 6 can be fitted with a ZF manual or Allison automatic gearbox; the 8 x 8 is fitted with a ZF automatic gearbox.

The all-steel Premium model two-seat sleeper-type cab is supplied by Renault Trucks and militarised by Sisu. Since 1997, Sisu and Renault Trucks have operated a co-operation agreement whereby Renault uses components from Sisu trucks and vice-versa. Renault markets Sisu trucks throughout Europe.

An applique armour package is available for the cab. Alternatively, a fully armoured exchange cab can be fitted in round four hours. This system was selected for the 110 commercially based Sisu 480-series 6 x4 tractor trucks currently in production for the French Army. Between 1998 and 2002, the Finnish Army received 220 E11T-6 x6 HMTVs. In 2001,27 E11T-8 x 8s fitted with a Multilift LHS were also supplied.

International marketing of the HMTV range began in 2001 and in 2003 Sisu

announced the E12T-6 x 6 and 8 x 8 variants for certain markets. These are fitted with a Deutz water-cooled diesel engine developing 450hp.