14 June 2002

Fitker tyre proves its fit for the job

A TYRE that should last longer, cope with faster operating speeds and run at lower inflation pressures. This sums up Fitker, the second generation 70 series low profile traction tyre from Kléber.

Progressively replacing the Super 8L and Super 9L and introduced in the mid-1980s, the new design is reckoned to give about the same levels of traction in the field, but much lower rates of wear, more even wear across the tread, and greater ride comfort thanks to more flexible sidewalls.

According to David Crinson, Michelin Group agricultural sales manager in the UK, the new tyre offers much the same traction and load capacity gains that come from replacing a standard 80 series tyre with a wider size from the low profile Super 8L/Super 9L line-up but with significantly improved wear and road performance.

He says: "Fitker is very much a dual-purpose tyre, which offers better characteristics for the increasing amount of road travel for which tractors are used these days, but without comprising field performance."

The improvements have been made largely as a result of studies into the forces to which a tyres tread is subjected as it rotates, especially on hard surfaces, and how the lugs move as a result.

"When we looked at the current tyre, we found the tread was subjected to very uneven loading as it made contact with the ground, took the full weight of the tractor, and then lifted from the ground again," explains Pierre Roulleau of Kléber. "Photographing the tyre through a glass floor panel revealed that the lugs move about a lot because of these changing and uneven loads, and there was a very noticeable flick as they lifted from the surface."

Recognising that the friction resulting from such movement causes the lugs to wear, Kléber engineers worked to eliminate the worst of these characteristics by paying particular attention to lug size and shape, and to the way it is anchored to the carcass. The carcass itself is designed to provide a more stable platform for the tread.

Lug loadings on the Fitker tyre are more progressive and more consistent across the tread, and the lugs move less during the contact phase of rotation. The design changes have not compromised traction or self-cleaning performance, says Pierre Roulleau, but the tyres wear more evenly and will last up to 30% longer than their older counterparts.

Sizes destined for the front axle of four-wheel-drive tractors are said to provide sharper steering response while being less sensitive to road camber and inaccurate tracking adjustment.

A 15% increase in sidewall flexibility improves ride comfort and vibration levels are lower across all speeds but especially at the top end of the tyres speed range, which extends to 31mph (50kph). &#42

KLÉBER FITKER

&#8226 16 front and rear sizes from 320/70R24 to 620/70R42.

&#8226 Speed rated up to 50kph.

&#8226 Higher load capacities at lower inflation pressures.

&#8226 Up to 30% longer life through reduced lug wear.

&#8226 Lower vibration and improved ride comfort.