Tractorpull New Zealand (TPNZ) is once again taking its sled to this year's Southern Field Days in Waimumu in what is a firm crowd favourite.

'We sort of refer to the Tractor Pull as a boy race, rural style," says TPNZ chairperson Vaughan Coy.

"The concept is making your tractor pull the furthest.

"He who pulls the furthest wins."

The TPNZ sled is a weight transfer tractor pull sled, which gets heavier as the tractor goes down the track.

Instead of a weight box, TPNZ uses a weight tractor that lifts itself vertically to increase the weight pulled by increasing resistance.

This means that all tractors, no matter size or horsepower, can race competitively, as the weight can be transferred evenly down the track and applied at a rate according to the tractor's class.

"Our sled is unique in the world in respect that it has a load cell in the chain.

"So it's recording and reporting back to the computer so it knows the weight and distance and how much to increase the weight by.

"Our tractor is different from a lot of sleds in the world in that it lifts the tractor off the ground to achieve the weight."

Coy said the tractor pull was about drivers getting the most out of their tractors.

The most successful drivers will have the right gear selection, throttle control and tyre pressure.

"Tractors are very easy to drive but hard to operate.

"It's a test of the driver's skill and how well they can read the track.

"They go in their own time; there is no time limit."

Entry classes include standard tractors over and under eleven tonne, modified and a pre-1985 class called 'old school'.

Sometimes, trucks even join in the fun.

"If it's got a drawbar on, we give it a go.

"We even had the Fijian rugby team pulling the sled at Waimumu a few years ago, so we are all about having fun."

Anyone wanting to enter the tractor pull at the Southern Field Days can download an entry form on the TPNZ website and pay the entry fee on the day.

History of tractor pulling

Tractor pulling began with literal horsepower when farmers would challenge each other to see whose draft horse could pull the most weight across the longest distance.

Barn doors were often used, being pulled behind the horse with more and more people stepping on the door as the pull progressed.

With tractors entering the agricultural scene, horses gave way to motorised tractors in the 1920s.

The first known tractor pulls were held in 1929 in the American Midwest, gaining popularity in the 1950s and 1960s when the motorsport began to spread to Canada, Australia and New Zealand.

by Claire Inkson