Double wheel

The Tiger 1 evolved from the VK3601 prototype tank, which had 32 road wheels of diameter 800mm. To fit all these wheels in a practical length, the designers put the axles 520mm apart and interleaved the wheels.

The first axle carried a pair of wheels close together. They were tucked in between the teeth of the sprocket, thus saving even more space. The second axle carried two widely separated wheels that overlapped the first pair. Wheel pairs were alternated like this all the way along. The idler wheel was tucked in between the wheels of the final axle.

The Tiger 1 was even heavier and the designers were forced to add a third wheel to the outside of each axle. They also reduced the spacing between axles to 515mm, and designed the outermost wheels to be removable for fitting the tank on rail cars. This resulted in a complex system of hubs and wheels that were not interchangable.

The first axles on the Tiger 1 carried what appeared to be a pair of wheels close together. In fact it was a single wheel with two tyres. Therefore the tank had 6 rows of tyres, but the manual refers to only 5 rows of wheels. These CAD images show how the tyres were mounted on the double wheel. This wheel was row 4, counting from the outside. It ran between the guide horns of the track.

The outer side of this double-tyred wheel had a protruding axle that carried a removable wheel. This diagram shows the axle. The double-tyred wheel was 205mm thick; the total width of the roadwheel assembly was 680mm, and the gap between adjacent wheels was 15mm [2] .

Part of the axle itself had to be removed in order to bring the tank within rail-transport width. This photo shows that the outer section of the axle was bolted on (the colours are not original).

This diagram shows the removable part of the axle. Note that the sides of the flange are cut away slightly, because the flange actually overlapped the road wheels on the adjacent axles. To remove an inner wheel without first removing this part, you would have to rotate the wheel so that these cutouts aligned with the wheel you were trying to remove.

This diagram shows a cross-section of the removable part. It had a cone welded inside it.

This is a section of the double wheel. The end of the axle had a large cap screwed into it. There was a hexagonal pipe on this cap.

The pipe had a hollow end, and within it there was an oil-filling tap.

This photo of the Bovington vehicle (the paint is NOT original) shows how the oil-filling tap was accessible through the cone in the outer part of the axle.

The Germans sometimes operated their Tigers with this first outer road wheel removed, because it tended to scoop mud into the suspension area. Usually they would remove both the wheel and the hub. The end of the inner axle was therefore exposed.

This diagram shows the end of the inner axle. To prevent the cap from working loose, a sheet-metal locking ring was screwed into the flange.

The ring (shown above) could be threaded onto the hexagonal pipe at intervals of 30 degrees. There were four locating holes in the flange, carefully positioned to divide the intervals down to 7.5 degrees. The locking ring therefore needed only 3.75 degrees of slack.

Sources

[1] Survey of vehicle 250122, Bovington, by David Byrden

[2] Russian intelligence diagrams of suspension

Copyright © David Byrden 1998-2007 except where indicated.

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