Every effort has been made over the years to identify an Allied tank that was similar to the German Tiger. None have ever really been successful although a few tanks came close, notably the T1E1.
Probably the closest was the American heavy tank T1 which was first considered on 22 May 1940 while the first tank, designated T1E2, was rolled out from the Baldwin Locomotive Works at Eddystone, Pennsylvania on 8 December 1941, the day following the Japanese attack on Pearl Harbor.
Tiger I was a cumulative development through VK 30.01 and VK36.01, steadily increasing in size and weight. The first running hull of VK45.01 (H), the prototype Tiger I, was completed in April 1942 and production began in July 1942, at the Henschel plant at Kassel.
Although it went through a number of changes in the design stage, the American heavy tank emerged weighing around 60 tons (American, unstowed) powered by a Wright, radial nine cylinder engine type G200, air-cooled and rated at 960hp driving through a Timken mechanical transmission with Twin Disc torque convertor and Hycon hydraulic control. Its maximum armour thickness was 76mm and it was armed with a three-inch anti-aircraft gun and a co-axial 37mm weapon.
Incidentally these guns were carried in a turret with a 69 inch diameter turret ring, which gives the lie to the old story that American industry was incapable of producing such a large turret ring until they geared up to make the Sherman. The tank ran on bogies with horizontal volute springs, four each side. But in most respects, speed, armour thickness and firepower, was no match for the German tank even then.
The American heavy tank appeared in three guises: as the M6 (with cast hull); the M6A1 (with welded hull, see above) primarily for British use with mechanical transmission (the British had been anxious to acquire an American heavy tank); and as the T1E1 with a gas (petrol)/electric transmission for the United States Army. However General Jacob Devers, then commanding the Armored Force, decreed that it made more sense to ship two lighter tanks such as the Sherman across the Atlantic instead of one heavy tank, so none of the American heavy tanks saw any action at all, unlike the Tiger.
True that in 1943 the pilot T1E1 was rearmed with a 90mm gun, although that was rejected by the Armored Force and that an even heavier tank, designated M6A2E1 was completed in 1945 with thicker frontal armour and a 105mm gun in an enormous turret, but this was ultimately built to test fire the gun for the proposed T29 heavy tank so it doesn’t really count.
In Britain the Churchill tank has been touted as the answer to the Tiger, but the Churchill, apart from having thicker frontal armour, is not in the same league as the Tiger. One British tank that may be worthy of consideration is the A43 Black Prince which had even thicker armour and was armed with the devastating Seventeen Pounder gun but it was dreadfully slow and was not completed until 1945, three years after the Tiger I.
See David Fletcher talk more about Black Prince in our Tank Chat.