The cancelled Grassland and Muck event was going to have been the first opportunity to see the new Claas Axion 900 Terra Trac in action in the UK.

On display would have been the top-of-the-range 445hp Axion 990 TT, which was due to have been powering a set of triple mowers.

Along with the smaller, 355hp Axion 930, these are the first half-tracks on the market to have a fully suspended track system. Their Terra Trac system has developed from the company’s wide experience gained over 30 years of rubber track development for the Lexion combine range.

To meet the different power transfer needs of a tractor and to handle the high levels of torque, the drive wheel on the tractors is larger than that on the Lexion, with spoke attached rubber blocks to aid self-cleaning. They use a force-locking drive and are maintained at a higher tension for even pressure distribution.

Combined with the front axle and four-point cab suspension on the Axion, its unique half-track suspension aids ground contact and reduces wheelslip, but gives the operator an unprecedented level of comfort compared to other tracked tractors, said Claas.

Drive comes through a standard CMatic transmission, but in place of the 'trumpet' housings there are ‘saxophones’, which bridge the differences in height and length. The actual drive is through a cardan shaft between the pto shaft and the tracks' intake shaft.

Unlike other track, this version is able to pivot over a range from +8° to -15°, which compared to full track, or rigidly mounted half-tracks, produces optimum ground contact at all times.

Tracks are available in 635mm, 735mm and 890mm widths and all have transport widths similar to tyres and below 3m. Total footprint on the widest 890mm track is 3.87m2, which is 35% larger when compared to a 900/60 R42 tyre. That means tractive power is reckoned to be 15% greater and ground pressure is reduced by 50%.

To avoid scuffing when turning, there is a unique intelligent steering system giving them similar driving characteristics to a wheeled machine. At speeds below 12kph, this gives automatic bias to the inner brake and to aid this steering assistance, within CEBIS, the operator can select from either Strong, Medium or Small pre-set levels.

The set-up also incorporates a height adjustment system of either a low, medium or upper position for the track units, aimed at getting the most out of the implement used behind the tractor.

* Also due to have been seen for the first time was Terra Tracs fitted to Claas' Jaguar self-propelled forage harvester.

This comes with an intelligent headland protection system to prevents damage to the grass cover.

Two Jaguars are available with it – the top-of-the-range 925hp 990TT and the 653hp 960TT. Independent tests have confirmed that even when the crawler track system is used with the narrowest track version (635 mm wide), the resulting contact area of more than 1.3 m2 is over twice that provided by 800-size tyres – though two other track variants with widths of 735 mm and 890 mm are also available.

Fitted with 635mm tracks the Jaguars remain within an external width of 3m while with 890 mm tracks, overall machine width is 3.5m. The suspended chassis enables a top speed of up to 40 km/h.