More traction and less compaction with central tyre inflation

The use of central tyre inflation systems (CTIS) has become common across the continent, particularly in Germany and the Netherlands, and is further growing in popularity.

Many manufacturers of tractors and self-propelled machinery have been offering the option for years, and we even see implement manufacturers adding the option to the extras list.

However, it’s still an expensive add-on and its use in Ireland has been limited to date. In recent years, more and more OEM manufacturers have begun offering retrofit systems – something which is beginning to become more popular in the UK.

On pages four and five, we look at IF and VF tyre technology, and the benefits they offer. The use of central tyre inflation systems plays a big role in getting the very most from such tyres, while not losing time, stopping and starting with compressors.

To find out whether or not such a system is really worth it, we caught up with Barry White from Whites Agri in north Co Dublin. Alongside his father Pat, the team farm over 1,800 acres of crops, do a little contracting and operate the well-known Agri merchant store.

In 2020, after some deliberation, Barry decided he would invest the extra €8,000 (at the time) in a tyre pressure regulation system when upgrading his Fendt 828 for the same again in a new tractor.

Fendt’s tyre pressure regulation system is known as VarioGrip. Like John Deere, Fendt’s integrated system is fitted very neatly, routed through the tractor’s chassis. At a glance of the outer rim, it wouldn’t even be spotted by the ordinary Joe soap. The Fendt system is capable of adapting the tyre pressure from 0.6 to 2.5 bar, on the move.

Air is supplied via a water-cooled double-compressor, a heavier compressor than what Fendt typically uses to feed its air brakes. It uses radial rotary feedthroughs which are located on both axles. Fendt uses a two-line solution, with the control line opening the tyre valve pneumatically and the inflation line inflating/deflating the tyre.

Fendt says the system can be fitted to flange and bar axles. It is adjusted at the touch of a button through the tractor’s terminal. It allows the operator to set the tyre pressure for field work and road use separately on both the front and rear axles. These settings are stored in the tractor’s terminal, and can be altered at any stage. According to Fendt, the list price on the VarioGrip system today is €12,000 plus VAT.

This particular system must be ordered on the tractor from new, and can’t be retrofitted. Fendt has in the region of 10 of these systems on tractors throughout Ireland.

Barry White, Lusk, Co Dublin

“The tyre inflation system is a hell of a job. We run three tractors on IF (increased flexion) tyres. I was always a fan of running my field tractors at lower pressures but it was time-consuming, manually inflating and deflating the tyres. The first day we went about setting up the Fendt 828 with the central tyre inflation system, it was pulling a 3m seven-leg Maschio ripper in potato ground.

“These implements are terribly hard to pull and we were really struggling to get traction, with huge amounts of wheel slip. We dropped the pressure to 0.8 bar and it totally transformed the operation.

“The change in tyre pressure gave the tractor more of a foothold. It meant we had four lugs in contact with the soil instead of three. I would easily say we gained 10-15% more traction instantly.

“The system is a gift, but you need to be sensible and understand how to get the most from it – you can also overdo it. I wouldn’t drop the pressure as low when using the six-furrow plough as I would with the five-furrow plough. Too much weight on the rear axle, such as a big plough, with very low pressure on the rear tyres would actually pull the rear tyre off the rim when turning – it has happened in this general area.

“It probably takes about five minutes to fully deflate, and a bit longer to inflate. If you have weight on the tractor it tends to deflate that bit quicker. I often engage the system on the road once I am getting near the field.

“And again, start to inflate when I’m on the last run on the headlands. That way, I’m not losing any time.

“For us, we found that the system was well worth the investment. I will definitely go for it again when I upgrade the tractor. I use it for ploughing (1.2 bar), spreading fertiliser (1 bar on trailed spreader, more for the 4t mounted spreader), ring rolling (0.6 bar) and pulling a trailer in the fields at harvest (0.6 bar).

“On the road, I run the tyres fully inflated (2.5 bar).”

There has been lots of research conducted on running tyres at various pressures. In the fields, low pressure reduces wheel spin and soil compaction. On the road, higher pressures reduce rolling resistance, premature wear and even fuel consumption.

There is no doubting the huge benefits central tyre inflation systems offer. A retrofit option is probably what would interest most in Ireland. Most of these are offered by Dutch, Austrian and German companies. Some retrofit manufacturers include TerraCare, PTG (now owned by Michelin), AgriBrink, STG and HRA.

Depending on the system, deflation times range from two minutes up to seven or eight minutes. Meanwhile, inflation tends to take a bit longer, ranging from three minutes to 10 minutes. All retrofit solutions that we are aware of have the air lines routed externally. One point to note is that this increases the working width of the tractor and with the cost associated, such a system would need to be minded.

There is a huge variation in pricing, such as whether or not the existing tractor would need a stronger compressor to power a similar system. There are currently no retrofit systems offered in Ireland. It’s difficult to get an exact grip on pricing, but it seems prices start in the region of €4,000 and range anywhere north of €12,000-€14,000.