Experimental, USA, WWII

T10 Mine Exploder – the Penny-farthing Tank

We love weird tanks at TankHistoria, and the T10 mine exploder is definitely no exception! As you have likely guessed, this vehicle was designed to clear minefields. Weighing as much as a Tiger I, it used a large set of heavy metal rollers to trigger mines. Because of its comical appearance, we have nicknamed it the penny-farthing tank.

The rollers were heavy and large so the could survive explosions, and their height kept the hull far away from the blast, but this also resulted in an exceptionally large and impractical machine.

Coming from the same family as other enormous rollers like the T1E3, this is the story of the T10 mine exploder.


The Mine Problem

Mines are one of a soldier’s biggest fears on the battlefield. They can be hidden, distributed quickly and are hard to counter. While mines are extremely effective at disabling or destroying tanks and other vehicles, this isn’t their sole purpose. Once a force encounters a minefield, it must either by bypassed or entered, requiring specialised teams to clear a path.

This means that a minefield can effectively funnel an attacking force into an area that better suits the defender if they choose to bypass it. If the attacking force decides to enter the minefield, they will be slowed down trying to clear a path.

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However, on its own an attacker will eventually get through a minefield, so they are most effective when paired with machine gun nests, artillery and mortars that can hit the force while it is clearing mines.

De-mining vehicle in action.
Flails are one of the most popular mine-clearing devices. They beat the ground and explode mines.

Therefore it is beneficial for an attacking force to bring equipment that can quickly clear mines while remaining safe from enemy fire.

Much work was done to solve this problem on all sides.

One of the main problems facing mine-clearing vehicles is that it is an inherently violent job; they need to be able to survive powerful explosions happening nearby.

The US investigated many ways of enabling a vehicle to survive such a role, including flails and explosive charges that could set off mines. Another technique that saw some use was dozer blades, which can simply push mines to the sides of the vehicle.

While this is an effective method of demining for an advance, it isn’t a long term solution as the pushed-aside mines must still be disposed of later.

Mine Rollers

One method that the US looked into was heavy metal rollers. The rollers would be pushed in front of a tank and their weight be sufficient to trigger any mines. Their basic, yet heavy-duty construction meant they would be essentially immune to the explosions.

The first roller, designated T1, came in early 1943. The T1 was comprised of three heavy metal rollers attached to an M3 medium tank, with two in front, and one at the rear.

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Each roller had a number of thick steel discs one meter in diameter. The T1 was effective at detonating mines and could survive the blasts, but it was extremely heavy and limited the M3’s manoeuvrability.

T1E1 attached to an M32.
The T1E1 device attached to the front of an M32 armored recovery vehicle. The M32’s crane is used to lift the rollers over obstacles and out of ditches.

A solution to this was to mount an improved version of the T1 (named the T1E1) onto an M32 armored recovery vehicle. The M32’s crane was connected to the rollers and could lift them up over obstacles. The roller system weighed 18 tons all in, but it did see some service. It was not a perfect machine though, as the M32 lacked proper offensive weaponry.

A number of other designs ensued, all following the same basic idea of pushing heavy rollers in front of a tank. The M1 (better known as the T1E3), for example, was made up of ten enormous steel discs attached to the front of a Sherman that kept its offensive capability.

Each disc was 2.5 meters in diameter and 70 mm thick, resulting in the T1E3’s overall weight of 30 tons – which was almost equal to the tank itself.

T1E3 and Sherman mine exploder setup.
A T1E3 attached to a Sherman. These rollers were driven by a chain connected to a gear on the drive sprocket. The system was used in action, but was exceptionally heavy.

In 1943 designers began looking into the idea of a self-propelled mine-clearing device. A concept was made that consisted of three wheels in a tricycle arrangement. The front two were 2.5 meters in diameter and contained their own engines for power. Between them were unpowered steel discs that followed the contours of the ground below.

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At the rear was a third wheel, connected to the front via a large frame. The device was known simply as the “Tricycle”, and served as the inspiration for the focus of this article, the T10.

The T10 Mine Exploder

The T10 had a few things in common with the Tricycle, it was to be self-propelled and feature wheels in a tricycle arrangement.

But instead of being a completely new device, or being pushed by another vehicle, it would be mounted directly onto the hull of a Sherman tank.

The type selected was an M4A2 built by Fisher. The M4A2 was the variant of Sherman powered by the General Motors 6046 twin-diesel engine. This powerplant was actually two individual 6-71 two-stroke diesels that shared a common output to the gearbox at the front of the tank, and could produce around 400 hp.

T10 mine exploder.
The T10 as it arrived at the Aberdeen Proving Ground for testing. Note that it has standard VVSS suspension. Also note the portions of armor missing above the tracks to make room for the rollers. The rollers are just visible in the background behind the tank.

The M4A2 was used in small quantities by the Marine Corps, but it was mostly sent overseas for use with other nations as the US used petrol-only Shermans in theater. This is likely why it was selected for conversion into a mine exploder.

This M4A2’s suspension bogies, tracks, sprockets and rear idlers were removed, and replaced with enormous steel mine rollers. The front rollers were 2.5 meters in diameter and almost a meter wide. They were connected to the final drives and powered by the M4A2’s engine.

Steering was achieved via speeding up or slowing down the front rollers, as it is on the standard tank.

T10 mine exploder at Aberdeen Proving Ground.
The T10 mine exploder. It is a strikingly odd vehicle.

There was a 1.6 meter wide gap between the front wheels the width of the tank’s belly, so a third, articulating roller was attached to the rear to ensure complete coverage was achieved. With this arrangement, the rollers covered a path 3.9 meters wide, significantly wider than the Sherman itself.

To make room for the large forward rollers, the front portions of the T10’s sides were removed – this can be seen in images of the vehicle.

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The rollers’ size not only made them resistant to mines, it also lifted the hull of the Sherman far off the ground which reduced the effects of mine explosions underneath. In fact, the bottom of the T10 was 1.5 meters off the ground.

T10 mine exploder front on.
Front view of the T10. The gap between the front rollers is covered by the rear trailing roller.

The T10 was toughened up even further with its rear belly armor increasing to 25 mm, up from 12.5 mm on a standard Sherman.

Despite the T10’s wild appearance, it was a self-propelled machine that had a fully-functional turret and main armament.

All in it weighed a staggering 59 tons – over 20 tons more than a standard M4A2, or around the same weight as a Tiger I.

T10 mine exploder traveling through mud.
The T10’s weight, and tendency of the rollers to clog up with mud, meant its abilities in rough terrain were limited.

So how did it perform? Seemingly, not very well.


The T10 mine exploder went through trials at the Aberdeen Proving Grounds in mid-1944, and failed to impress. Top speed of the vehicle was 7 mph on road, and 2 mph during mine-clearing work.

The rollers were soon found to accumulate so much mud between the discs that they would essentially become solid cylinders and loose their ability to detonate mines.

T10 mine exploder rear view of rollers and mud scrapers.
This image gives a good view of the mud scrapers behind the rollers. They are the star-shaped objects. The vertical plate at the very rear of the T10 was a “push-plate”, for other vehicles to give the T10 a nudge should it bog down.

Therefore star-shaped metal mud scrapers were added behind each roller that scraped the built-up mud as they turned.

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However the massive size and weight of the T10 could not be ignored, and would eventually prove to be its undoing. It was simply too slow, too heavy, and too impractical to see any use in service. It was cancelled near the end of 1944.