Profile
- Type
- Upgraded T-55 main battle tank
- Conflict side
- Ukraine
- Origin
- Slovenia
- Service note
- 1990s Slovenian modernization; transferred to Ukraine in 2022
Tanks
M-55S
The M-55S is Slovenia's modernized T-55 main battle tank, rebuilt by ST Ravne with a 105 mm gun, explosive reactive armor, fire-control upgrades, laser-warning equipment, and NATO-compatible ammunition. During the Russia-Ukraine War, Slovenia committed 28 M-55S tanks to Ukraine through a ring exchange with Germany, making the type a legacy Soviet chassis adapted for Western-supported Ukrainian armored forces.
Service History
- In service
- Slovenian reserve-unit tank before the 2022 transfer to Ukraine
- Used by
- Slovenian Armed Forces, Ukrainian Armed Forces
- Wars
- Russia-Ukraine War
Production History
Specifications
- Crew
- 4
- Armament
- 105 mm gun, 12.7 mm machine gun, and 7.62 mm coaxial machine gun
- Combat weight
- 38,000 kg
- Dimensions
- 9,900 mm length, 3,500 mm width, 2,390 mm height
- Mobility
- 580 hp-class diesel, 50 km/h maximum speed, 420 km operational range
- Protection
- Explosive reactive armor, fire protection, CBRN protection, and laser-radiation detection system
Conflict Usage
- Russia-Ukraine War
- Side: Ukraine
Slovenia agreed in September 2022 to transfer 28 M-55S tanks to Ukraine through a German-backed ring exchange, placing the upgraded T-55 variant in Ukrainian service during the war.
M-55S Images
Related Weapon Systems
Leopard 1A5Main battle tankThe Leopard 1A5 is a German main battle tank modernization centered on improved fire control, thermal sighting, and the 105 mm L7-series gun. In the Russia-Ukraine War, refurbished A5-family tanks from European industrial stocks give Ukrainian armored units a lighter Western tank with good mobility and logistics support, but less passive protection than newer Leopard 2 variants.
Strv 122Main battle tankThe Strv 122 is Sweden's upgraded Leopard 2 main battle tank, adapted for Swedish service with reinforced protection, Swedish communications, smoke launchers, and a four-person crew. Sweden transferred ten tanks to Ukraine in 2023, pairing the donation with training for Ukrainian crews before the vehicles were fielded in the Russia-Ukraine War.
Challenger 2Main battle tankThe Challenger 2 is a British third-generation main battle tank built around a rifled 120 mm gun, heavy composite armor, and four-person crew operations. In the Russia-Ukraine War, the United Kingdom supplied a small squadron to Ukraine as one of the first Western main battle tank transfers of the full-scale invasion.
PT-91 TwardyMain battle tankThe PT-91 Twardy is a Polish main battle tank developed from the T-72M1 with domestic upgrades including ERAWA explosive reactive armor, improved fire-control equipment, and an 850 hp diesel powerpack. In the Russia-Ukraine War it represents a Polish-supplied T-72-family tank type used to expand Ukraine's armored force with a familiar three-crew, autoloaded 125 mm platform.
AHS Krab155 mm tracked self-propelled howitzerThe AHS Krab is a Polish 155 mm tracked self-propelled howitzer built by Huta Stalowa Wola around a NATO-standard 52-caliber gun, an armored tracked chassis, and modern fire-control equipment. In Ukrainian service it gives artillery units a mobile Western-caliber gun able to fire standard 155 mm ammunition, displace after missions, and operate in counter-battery-threatened sectors of the Russia-Ukraine War.
AS-90155 mm tracked self-propelled howitzerThe AS-90 is a British tracked 155 mm self-propelled howitzer built for armored, mobile indirect fire support. In the Russia-Ukraine War it represents a UK-donated NATO-caliber artillery system for Ukrainian forces, combining a protected tracked chassis, 155 mm ammunition compatibility, rapid burst fire, and a conventional range of about 24.7 km.Sources
ST RAVNE M-55 S Main Battle TankPublisher: Slovenian Armed Forces | Note: Official equipment page for the M-55S role, T-55 upgrade background, manufacturer, armament, protection systems, dimensions, mobility, and crew. | Accessed: 2026-06-20Prime Minister Robert Golob in a telephone conversation with German Chancellor Olaf Scholz about current European affairsPublisher: Government of the Republic of Slovenia | Note: Direct Russia-Ukraine War conflict-use source for Slovenia's agreement to send 28 M-55S tanks to Ukraine through a ring exchange with Germany. | Accessed: 2026-06-20T-55 in Slovenian Service and M-55SPublisher: Tank Encyclopedia | Note: Secondary background reference for the Slovenian T-55 modernization program, M-55S conversion count, 105 mm gun upgrade, fire-control work, and NATO ammunition context. | Accessed: 2026-06-20File:M-55S SV.jpgPublisher: Wikimedia Commons | Note: Primary image of a Slovenian Armed Forces M-55S; file page lists author, date, source, and CC BY-SA 4.0 licensing. | Accessed: 2026-06-20File:Slovenian T-55.jpgPublisher: Wikimedia Commons | Note: Additional M-55S image sourced to the Slovenian Ministry of Defence and listed under Creative Commons Attribution 3.0 terms. | Accessed: 2026-06-20