The head of Michelin’s agricultural technical team in the UK and Ireland has advised farmers to focus more time on selecting the correct tyres for the rear of their harvesters, rather than putting all the focus on the front axle, as traditionally happens.
Customer engineering support manager Gordon Brookes said the issue was increasing in importance as harvesters grow in size, weight and power. He also warned that most machinery dealers don’t focus heavily on tyres when securing an order, so farmers should seek expert advice from their tyre manufacturer or dealer.
Offering advice ahead of the 2019 harvest season, he said the rear axle was the smallest tyre, so it was always going to be where damage was most likely to be done.
“Farmers naturally look at the front because that’s where everything’s going on; while often forgetting that when the combine is full, the back end is extremely heavy despite being on a very small tyre,” he added. “And when travelling without the header mounted, there’s no weight transfer from the rear axle, so the rear tyre loads can be very high. Sometimes you’ll even see the rear axle specified on the same tyres you’d fit on a loader, so shifting some of the focus from front to rear could pay huge dividends as far as soil compaction is concerned.”
While four-wheel-drive harvesters require lugged tyres on the rear, Brookes said farmers could access a much wider range of fitments if they’re specifying a two-wheel-drive machine.
“If minimising compaction is your number one issue then you can select a flotation tyre like the Michelin CargoXBib,” he added. “That’s designed to spread the weight of laden agricultural trailers, so it’s always going to be better at reducing compaction than a smaller fitment.”
Another area where Mr Brookes felt farmers should focus their attention is tyre pressures.
“Nearly all machinery manufacturers leave tyres at the fitting pressure – normally around 35psi – and then the dealer is supposed to amend the pressure if it’s appropriate prior to delivery,” he said. “But only a small percentage do, invariably as they don’t know how the machine will be used.
“If the farmer is combining linseed, for example, it has a different density to wheat or barley – and the tyre pressures are dependent on what you are harvesting.”
Michelin is happy to provide bespoke tyre pressure recommendations if a harvester is on Michelin tyres. It will even arrange for one of its Account Managers to come out to weigh a machine on-site and calculate the optimum pressures.
Mr Brookes said that setting up new harvester tyres correctly is essential, particularly if the machine is using a high technology fitment like a tyre from its CerexBib family.
“Bear in mind that a typical combine might have four different headers and they’ll all be different weights,” he added. “The tyre pressures will be different in each scenario.”
The final tip for specifying harvester tyres is to opt for the latest CFO+ (Cyclic Field Operations) rated tyres where possible, because they offer the highest load capacity and the lowest pressure for a given load.
“CFO+ rated tyres are based on a 1,500m cycle, and if that’s not enough to fill the tank, then you most likely haven’t got a good crop!” Mr Brookes said. “There are other cyclic markings for other tyres on the market, but the load benefit isn’t as high, and the cycle distance isn’t as great.
“Some are only up to 600m, plus they can come with other limitations for things like working on side slopes. It pays to specify the best tyre you can from the outset, and then enjoy the benefits.”
Farmers can seek expert tyre support through their local Michelin Exelagri dealer, a network of more than 50 dealerships in the UK and Ireland that has been audited to ensure it can offer the support required to help farmers extract the maximum performance from their tyres.
For more information visit: http://agricultural.michelin.co.uk.
