MICHELIN TRACKS & TYRES EUROPEAN TOUR Written by Mark Hatton I was recently, lucky enough, to be invited to attend the UK leg of the Michelin Tracks and Tyres European Tour in Cambridgeshire. The event was to showcase the features and benefits of their VF AXIOBIB 2 tyres, the latest track technology and the benefits of using the PTG Central Tyre inflation systems to vary tyre pressures to improve efficiencies, which we will focus on in this article, it turns out there’s much more to tyres than just being black and round!
With tractors supplied by New Holland, a pair of identical T7.270, one fitted with Michelin’s Very high Flexion VF 710/60 R42 and VF 600/60 R30 Axiobib 2 tyres and the PTG Central Tyre inflation system, the other tractor fitted with 650/65 R42 and 540/65 R30 Multibib tyres. The event began with a demonstration to highlight the difference in tractive effort between different tyre pressures. To create the load a New Holland T8 SmartTrax was deployed to create resistance: lets call it the brake tractor method. This keeps the tractor at a constant speed, as it accelerates the wheels increase the tractive effort. This is the most reliable method for comparing traction efficiency, in the form of weight and resistance. This is done to measure the tractive effort at the drawbar. A sensor integrated into the drawbar linking the tractor to the convoy will measure this effort, which is a value in decanewtons (or kg). Linked to this sensor, a live display screen, allow us to see this value. The higher the value, the higher the tractive effort. In other words, the higher the tractor's traction. Two runs were made with the T7.270, fitted with, Michelin’s Very high Flexion VF 710/60 R42 and VF 600/60 R30 Axiobib 2 tyres at different pressures, altered via the PTG Central Tyre inflation system. At a constant speed of 4.6 km/h, we can see an average of 6800 decanewtons or kg The higher the value, the higher the tractive effort. In other words, the higher the tractor's traction.
By reducing the tyre pressures from 16 Psi to 10 Psi, we saw an increase of 17% tractive effort from of 6800 decanewtons to 8000 daN. This increase provides benefits in the way of reduced wheel slippage, less soil structure damage, increased fuel efficiency and overall improved machine productivity. The second test was a demonstration comparing tyre sizes, type of type (ULTRAFLEX and MULTIBIB) and tyre pressures. To achieve this, the New Holland T8.SmartTrax was again deployed to act as the resistance, by connecting both of the T7.270’s with a cable, which passes through a pulley attached to the T8.Smarttracx , Like for the previous tests, the tractors are set to travel at an identical speed. We will see over a given distance how many meters are gained with the more efficient configuration. The tyres pressure were again set on both machines, for the AXIOBIB 2 with CTIS is set as the previous test: rear 0.7b (10 Psi) and 0.6 b (9Psi) The tractor fitted with the Multibib, a pressure of 23 Psi, was selected as the most used pressure by farmers in UK. As the tractors set off down the field, it was easy to see the difference between the two. The T7.270 fitted with the VF AXIOBIB tyres, set at a lower pressure quickly pulled ahead of the tractor fitted with the Multibib tyre. As with the previous test, the benefits of the different
58 DIRECT DRILLER MAGAZINE
ISSUE 16 | JANUARY 2022
