It often happens to me that an initially small article grows into a colossus. Likewise, my article on Tiger II V2 got slightly out of hand. This part of the article is now published separately as complete background on the Tiger II tracks for the tech-savvy.
Tiger II V2 was a test vehicle, and it is therefore not surprising that many test drives were made with it. The results of these test drives would eventually trigger all kinds of changes and developments. Significant changes to the tracks were also initiated in this way. In this article, I devote further attention to the design evolution of the Tiger II’s tracks.
Table of Contents
- Breaking new ground
- Legacy of the Panther II
- Elusive Designation
- Why Go Double?
- Attention to Detail
- On the Right Track
- Doubling Down on Single Links
Breaking new ground
The Tiger II tracks were a complete departure from the usual German design. They consisted of so-called Doppelkettenglieder (double track links). According to the preliminary manual1, each double-track link incorporated the following parts:
- 1 bridge link
- 1 intermediate link
- 3 side links, “as auxiliary links by means of joint bars”
- 2 track pins
It thus took both a bridge and intermediate link to form a single ‘main link’, a rather complex design. Furthermore, each intermediate or connecting link consisted of several parts. Since the connecting link itself was quite narrow, three side links were used to connect it to the bridge link.
The bridge link was rather wider than the connecting link: 800 mm to be precise. It formed the main contact to the ground as it had two grousers (ground contact bars) with five chevrons on its face to improve grip. The bridge link provided two guide teeth for track control spaced 212 mm apart. It is worth mentioning the inner guide is 10 mm shorter than its outer counterpart, which is 100 mm high. It seems that the inner guide tooth was shortened due to space constraints at the drive and idler wheels. There are no such size restrictions for the outer tooth, which is apparently why it remained somewhat longer.
The track was designed by the firm Ritscher-Moorburg (Moorburger Treckerwerke), which had plenty of experience with the track design for various Wehrmacht vehicles – like the Tiger I and various half-tracks2.
According to the official manual, there were 90 links per track, but in some cases there could be 92. The sprocket of the drive wheel was of such pitch that it engaged every link, and it had 18 teeth. The initial Geländekette (cross-country track) described above was designated Gg 24/800/3003.
The 800 mm wide combat track did, however, protrude beyond the allowed railway loading gauge. This meant the wagons would not clear all tunnels nor oncoming traffic. Therefore, a complementary 660 mm wide Verladekette (transport track) was available, named Gg 24/660/300. This track was originally intended as combat track of the Panther II1, but this vehicle never entered series production.
Legacy of the Panther II
The origin of the double track links can be traced back to the Panther II, which was in development around the same time as the Tiger II. In early 1943, an attempted unification with MAN’s Panther II was initiated by Wa Prüf 6/III. Much to the dismay of Henschel’s designers, many Panther parts had to be incorporated into their design4. The rubber-saving steel wheels designed for the Panther II also found their way into the Tiger II design.
A quick peek at Tiger II drawing number “021 C 49505-U2” for the Laufrad (roadwheel) learns us that the wheel was indeed originally designed for the Panther II as indicated by its drawing number “021 D 50204” – which falls in the series reserved for the Panther II 5. The steel wheels were first fitted to Panther chassis number V1, along with a new type of track and a modified 20-teeth sprocket. Panther V1 underwent testing with these wheels on June 29, 1943 at the Märzfeld Wellenbahn.
The track on V1 deserves our attention: it was apparently specially designed for use with the new steel wheels and, unlike stated by Macdougall and Neely6, is actually distinct from the later “Gg 24” track used on the Panther II. The number of pin lugs differs from the final version (both in number and width). In addition, the bridge link is more robust with thicker guide teeth with three vertical reinforcing ribs. Furthermore, the chevrons on the track surface and the rectangular reinforcement pattern are arranged differently.
It is noteworthy that the use of steel wheels apparently went hand in hand with double-link tracks. The combination of the two was also proposed for the Panther (I), but apparently never materialized. On January, 4, 1944, this was discussed: “This new track is to consist of a cast link with one guide tooth and two cleats and a forged Zwischenglied (connecting link). Due to the low number needed, it would be better to cast this Zwischenglied.”7
The official designation of the double-link tracks is somewhat problematic. The prefix “Gg” does not adhere to the general three-letter system used to explain a track’s properties. Witthuhn, author of “Die Sohlen der Tiger”, comes up with the explanation that the capital G means the track is still being trialled8, but this is not very convincing. In “Panzerketten”, Schwarzmann poses a more plausible explanation in which “Gg” would be used to indicate materials: G for Gußstahl (cast iron bridge link) and g for geschmiedet (forged connecting link)9.
Why Go Double?
When confronted with the unusual track design, Allied intelligence could only guess the reason for using two link types. They noted, “the reasons for the German employment of two types of track link are difficult to assess”10. They reasoned that with such a heavy vehicle, one link would probably should be laterally strong and therefore feature two grousers. It was also suggested the placement of the track pin lugs opposite of each other, would better conduct stresses and benefit track strength.
The same report praised the suspension and track design for its excellent track control characteristics: “there are no less than fifteen guide horn under the control of the bogie wheels. It will be appreciated that steering, and particularly skid steering, is very much facilitated by this arrangement.” The report concluded that “In any case, some decided benefits must be obtained in order to justify the use of two forms of track link”10.
And indeed, according to the Germans, there were distinct advantages to the novel track making the effort worthwhile. Reasons underlying the unconventional design included its desired material properties as well as the wish to obtain a standardized track. Henschel’s chief designer Edwin Aders explains in his 1945 memorandum:
“The desire to manufacture at least part of the links by forging, as well as to create a uniform track for the right and left side, without different running resistances, led to a track with cast links with guide teeth for track control and a drop forged, though presently also cast, connecting link consisting of multiple parts”Aders, “Die Tigertypen E Und B: Entstehung Und Entwicklung.” [translation by author]
An advantage of forging is that the end product is stronger than when cast or machined. The forged connecting links are easily recognizable by their smooth-textured surface. With very early variants, the joint bars appear to have been forged as well. However, after some time connecting links started being cast from Manganese steel, just like the bridge link. From that point forward, both link types had a rectangular pattern on their track face for added strength.
Furthermore, the problem of a distinct left and right track was never solved satisfactorily for the Tiger I4. The fact that there were two links in use, which were in-fact mirror images of each other, made for a logistical nightmare. This problem was “solved” by abolishing dedicated tracks for either side as of the 21st Tiger I (October 1942)11.
In practice, this meant the left track was fitted on the right side as well, albeit in reverse. Problem solved? Not really, as this had a major drawback; because one track ran forward and the other in reverse, the tracks wore differently resulting in unequal rolling resistance12. This would could cause the tank to pull to one side by itself, requiring constant course adjustments. The cleverly conceived two-piece link design eliminated all of these problems while still allowing the use of an asymmetric link.
Attention to Detail
On paper, the double-link track was the perfect solution. However, the first teething problems soon came to light during an inspection of the first prototype Tiger II, chassis No. V1, in December 1943. Without prior testing, the head of Henschel’s proving ground at Haustenbeck-Lippe, Kurt Arnoldt, noticed many potential problems with the design13. In his opinion, the track had little sideways stability compared to that of the Tiger I.
He foresaw that after uneven wear of the connector’s side links, the track could bend, in some cases causing the links to pull and push on each other. In that scenario, the guide teeth would start to “restlessly” wander from left to right and rub against the rims of the bogie wheels – more so than on the Tiger I.
Furthermore, the angular design of the guide teeth appeared unfavourable. Arnoldt said this could cause problems, especially at the point where the teeth pass in-between the bogie wheels. It was further noted that snow or sand could settle on notches in the guide teeth with the necessary consequences.
In relation to this, Aders mentioned that the tolerance between the bogie wheel and guide tooth position, which at the urging of the Heereswaffenamt14 had been reduced to just 2 mm, was far too small. Aders concluded that the track was too “loose”, i.e. had little resistance to torsion.
And that wasn’t all. Arnoldt noted that it would be wise to install a track pin return plate, just to be on the safe side13. A track pin return plate pushes back track pins that work their way loose and prevents them from falling out, disconnecting the track links. The Soviet T-34 is notorious for its use of a pin return plate as its sole measure to secure its track pins. While return plates also found their use in German designs, such as the Tiger I and Panther, their tracks were first and foremost secured using rings with cotter pins.
Arnoldt recognized that with the tracks positioned even closer to the hull side than on the Tiger I, the danger of bending or breaking track pins was even greater. The report further states that the use of such a plate was foreseen and trials would commence shortly. Ostensibly, the plate did not achieve the desired results, as it was never adopted. Later, Aders also commented on the issue, which remained unsolved:
“The new type of track showed, to an even greater extend than with the Tiger E, the disruptive property that the pins wander in the direction of the hull, where they catch on the backside and break.”Aders, “Die Tigertypen E Und B: Entstehung Und Entwicklung.” [translation by author]
Worse for wear
Subsequent test drives brought yet another issue to light. After a test with V2 on March 17, 1944, it became evident that every second sprocket tooth was badly worn. This occurred after driving only 804 km15. After measuring several links, it turned out that they were of uneven pitch. Due to manufacturing imprecisions, the pitch of connecting links was up to 10 mm larger than that of bridge links. This caused the former to rub against the drive teeth with the necessary abrasion as a result, literally carving out the sprocket teeth.
Another problem that arose was the track’s tendency to climb onto the sprocket. It was not clear whether this was caused by the track’s “looseness” or the aforementioned uneven pitch4. Arnoldt later claimed the only solution was to use longer guide teeth, but there is no evidence of a design attempt with such a feature16.
Possibly, longer sprocket teeth would also have alleviated the tendency for track-jumping. A drawing of a redesigned sprocket ring was dated 30 July 1944. This appears to have been created in reaction to one of Arnoldt’s statements from 1943: “It cannot be excluded that the sprocket tooth is too short. Experiments are still being carried out in this regard.”13 The improved sprocket was finally introduced in March 1945, but more about that later.
On the Right Track
To remedy the most serious problems with the original track, an alternative design was introduced in May 194417. The Gg 26/800/300 track was not as flexible as the previous design. Now only bridge links engaged with a 9-teeth sprocket and the one-piece connecting links better resisted sideways motion. The sprocket ring had a stepped outline, with slight indentation to accommodate the connector links wrapping around the drive wheel.
A drawback of this design was that the load was distributed over a reduced number of sprocket teeth. This caused excessive wear on the remaining 9 teeth. According to an Allied report, the driving sprockets on a number of examined vehicles were “very badly worn after what would be considered a small amount of running”10.
The Soviets commented on the same issue in their October 1944 Bulletin of the Tank Industry: “This design of the track led to a sharp reduction in the number of teeth on the drive wheel and, as a consequence, to their rapid failure”18.
Doubling Down on Single Links
To overcome the existing problems, the unsuccessful double-link design was reconsidered. A new single-link design, Kgs 73/800/152, was introduced, accompanied by the reintroduction of an 18-teeth sprocket. As the design was asymmetrical, there were again mirrored left and right-handed tracks. The design is reminiscent of the Tiger I’s Kgs 63/725/130 track with trapezoid-shaped partitions on its surface. The new link also had openings for the installation of two Hammerstollen, an accessory to improve grip on frozen surfaces9.
According to Spielberger, the single-link track was introduced as early as November 194419. They were first used on a few Tigers delivered to the sPzAbt 506 that took part in the Battle of the Bulge. These Tigers were also equipped with the initial 18-teeth sprocket.
The “Kgs 73” was not mounted on a large scale until March 194520. However, at that time many Tigers were delivered to the troops on transport tracks. It seems that, due to the deteriorating war situation and the approaching front, inadequate quantities of the new tracks were able to reach the assembly line at Kassel-Mittelfeld. The photo below supposedly shows piles of Kgs 73/800/152 tracks, stranded at Paderborn station, some 100 km from Kassel21.
Coinciding with the introduction of the new track, a new 18-teeth sprocket, with longer, pointier teeth was introduced22. The 18 sprocket teeth were 1.5 mm longer and 3 mm thicker than before. Ostensibly, this sprocket solved the problem of excessive wear – both by increasing the number and thickness of teeth.
It was doubted whether the “Kgs 73” was actually used in the field, as adoption started only just before the assembly line was overrun. Nowadays, there is enough photographic evidence to corroborate this type of track was used on a couple of Tigers from sPzAbt 507 and 510/511. A CIOS investigation team also confirmed there were Tigers on the assembly line with single-link tracks16.
With the introduction of the single-link track, several changes to the turret were also being introduced. One of the changes was an updated arrangement of the spare track hangers on the turret sides. Instead of the original four sets of hangers on either side, the updated turrets disposed of six sets of hangers20. Every pair of hangers would accommodate a single link. This modification was not very widespread, and photos from the Henschel plant show turrets with both the updated and original hanger pattern awaiting installation.
Based on the hangers, which appear identical all round the turret, it may be concluded that only the left-hand tracks were to be used in the field23. If this is correct, it can be assumed that, as with the Tiger I, it was decided to drop the right-hand links altogether. In the small selection of photos of Tiger IIs with the Kgs 73 track, in which the track direction is recognizable, it appears that a left track is indeed fitted on the right side.
After the war, two test vehicles with the single-link tracks were found by the Allies. Both sported left and right track links. Chassis No. 280 006, aka V6, was found at the Heereswaffenamt’s winter test facility in St. Johann. This vehicle was sold to Sweden in 1947 and used for various tests. It was shot-up during the 50s and besides its engine and transmission, only one hatch remains of it24. The other vehicle was chassis No. 280 009/12 at Henschel’s Panzerversuchsstation 96 in Haustenbeck. At some point after the war, V2’s original Gg 24/800/300 tracks swapped for the latter vehicle’s single-link tracks. This makes V2 the only Tiger II left today with this type of track.
Following are more detail shots of the Kgs 73/800/152 track as seen on V2 today. The chevrons are worn down quite a bit. Miraculously, the left and right tracks on V2 have been fitted correctly.