Review: Joskin gear drive topper

By: Jaiden Drought

Joskin gear drive topper Joskin gear drive topper
Joskin gear drive topper Joskin gear drive topper
Joskin gear drive topper Joskin gear drive topper
Joskin gear drive topper Joskin gear drive topper
Joskin gear drive topper Joskin gear drive topper
Joskin gear drive topper Joskin gear drive topper

Jaiden Drought puts the Joskin gear drive topper to the test and comes away impressed.

Review: Joskin gear drive topper
Joskin gear drive topper

In recent years the trend of topping in front of the cows has emerged. This will increase intake as wilted grass reduces moisture content, meaning the cows can physically fit more in their stomach.

A beneficial flipside of this is the pasture quality is also better, as the rubbish in the base and stalky grass in the sward is reduced, increasing the quality and palatability of grass into the next round.

This is not a new idea of course, but more and more people are adopting the technique which raises the question: do you buy a regular disc mower which you can use to mow your own hay and silage as well, or do you buy a dedicated topper?

Like most machines, both have their pros and cons. But with a topper you won't mow the paddocks anywhere near as low, which increases residuals and allows the grass to grow back faster. Instead of mowing low you could easily go from having a heap of grass, then topping, only to find you have no grass the next round, particularly if the weather turns dry.

Machine features

  • A wide range of blade and rotor options are available, but the Joskin BJ275 comes standard with two rotors each equipped with three blades (this configuration is widely regarded as the best option to keep cut quality good at high forward speeds).
  • Removable and retractable blades in the case of striking hard obstacles, which helps reduce shock in the transmission and increases blade life.
  • A large gap between the blades which allows consistent chopping and mulching without slowing down or becoming blocked.
  • The spiral effect of the blades sucks the material up, leaving a smooth finish because material isn't clogging the blades significantly (this also reduces power requirements).
  • Shear-bolt protection of the PTO shaft for added protection.
  • Several accessories such as rollers, aerators and chains can be added later with no additional mounting points.
  • The skids have six different height options from 40mm to 150mm and are Hardox plated which significantly reduces wear.
  • The machine is designed so no water is left in the cavities, which makes cleaning easier and will reduce the risk of rusting.
  • Construction using high tensile steel to keep strength up and weight down.

Joskin _topper _7


Often toppers are belt-driven but the transmission on the Joskin BJ series toppers is actually dubbed the 'hyper-flexible' transmission, giving direct drive to the rotors via four round rubber shock absorbers.

These are mounted on the universal joints with the main task of absorbing vibrations and shock from the rotors which isn't then relayed through the gearbox, PTO shaft and tractor. This works in a very similar fashion to the rubber mounting block on some cultivation discs, where they have a certain amount of 'give' to reduce stress through the machine. The machine is driven at 1000rpm PTO speed, which really gets the blades going and allows it to hack through some tough rushes. I had a wee sneak peak at it while it was on the tractor.


To buy a topper or disc mower really is the decision you have to make. These machines are better suited to topping after the cows come out rather than beforehand, as you are running over the grass before it is mowed which doesn't leave an impeccable job if I'm honest.

In shorter grass or for a landscaping operation the BJ 275/C2 is very well made and designed with longevity in mind. In classic Joskin fashion where almost nothing is overlooked, for greater topping outputs, the TRT 750 C6 triple topper has 7.5m cutting width with two rear butterfly toppers and a front mounted machine.

Why mow with 2.75m when you can do 7.5m in one hit? Now that really is my kind of topper.

Thumbs up

  • Robust construction
  • Shot blast and two-pack paint for quality finish
  • Rubber shock absorbers help reduce transmission stress
  • Two rotors with three blades per rotor allowing high forward speed
  • The rotors suck the material up meaning it won't slow rotor speed and significantly reduces blocking
  • Skids have six settings are Hardox coated to reduce wear
  • Large gap between the deck and the blades means bulky material has room to move
  • The blades are large and designed to swing back if an obstacle is hit
  • A range of accessories can be attached such as chains, rollers and aerators

Thumbs down

  • It's a one trick pony: you can't mow silage or hay with it. However for the really tough stuff these are much more robust
  • Because you run over the grass before it's cut it doesn't leave a perfect finish in longer grass

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