Kubota may not be a household name in the gas-powered UTV market, nor does it need to be. Instead, it markets its quad vehicles as RTVs, or Rugged Terrain Vehicles, with a focus on workhorse reliability and longevity. This sits well within the rest of the Kubota range of tractors, loaders, and other construction and farming machinery.
What Sets Kubota Apart?
The thing that differentiates Kubota from the likes of Polaris or Can-Am, as well as their Japanese cousins Honda and Kawasaki, is a devout following for all things diesel. Many of the company's bestselling RTVs are based on the grunt and low-end torque of gutsy oil burners that promise hours of reliable performance, lower maintenance, and lower running costs.
The niche Kubota has carved for itself means you'll find its RTVs more on farms, ranches, and construction sites doing the heavy lifting rather than speeding down trails or racetracks. That's not to say they're not built tough or short of power. Bullet-proof engines aside, all Kubota RTVs are built around a sturdy chassis capable of lugging heavy loads and class-leading towing, a proprietary Variable Hydro Transmission (to eliminate drive belt wear), larger fuel tanks for longer work shifts, and independent suspension offering all the comfort and handling required on rugged terrains. And if you tire of diesel reliability, Kubota also offers capable gas-powered side-by-sides in both compact and full sizes.
The huge dealer and service network across the US (over 1100 locations) also warrants that any issues are easily and quickly resolved. While you'll be spending a lot less on maintenance on a well-serviced Kubota RTV, there will be times when common issues that plague other brands, specifically front and rear axles, will flare up and present an obstacle. These can be replaced, either with OEM parts from dealerships or, more commonly, with aftermarket Kubota ATV axles from dozens of renowned parts makers.
Axle Basics: Keep Your Wheels Turning
Constant velocity, or CV axles, are what get your Kubota RTV up and running. They transfer power from diesel or gas engines and the hydraulic transmission down through the wheels. It is a simple task until you consider that they are also responsible for steering and wheel articulation, allowing you to manoeuvre the vehicle. Factor in the constant stresses acting on axles when going through typical off-roading conditions and the extra weight of anything you have in the cargo bed, and you can soon expect torn CV boots, stuck bearings, overheating, and axles ready to break in two.
Any Kubota RTV rated for heavy-duty work, like the RTV-X900 or the company's most competent UTV, the RTV-X1140, will have factory drive and half-shaft options that outlast those in all other UTV brands. This is besides the huge torque they're fed from the diesel engine. While most Kubota owners skip lift kits, boots will tear when constantly scraping against sharper rocks or branches, leading to a loss of lubricating grease, axle binding and worn bearings.
Moreover, boots with minor hairline cracks cause gradual wear due to dust and water getting in and eating away at the metal parts from the inside. Any damage usually causes grinding noises when trying to accelerate or brake, evident vibrations when stepping on the gas, and sputtering or clunking noises when putting the RTV in gear. Steering becomes less responsive, to the point where it's almost impossible to turn. Heavy impact and fatigued parts can also rip the shaft straight off the joint or bend the whole axle until the vehicle is unable to transfer power.
When to Replace: OEM vs. Aftermarket Upgrades?
If your Kubota ATV axles have seen more than their fair share of abuse, it's time to consider replacements. This can save you from more serious and costly issues, particularly with the suspension and, in some cases, the transmission. Additionally, you won't be risking your safety or having to postpone work due to underperforming units. Though axle wear often comes on gradually, it can also cause some nasty surprises when you least expect it. So, a spare or two is just common sense.
Axles come pre-assembled with shafts, joints, and boots. Anyone looking for much of the same performance from their Kubota ATV should shop for replacement parts directly from dealerships. But with better quality, beefier builds, and more robust materials, aftermarket options not only work better, but they also last longer.
Most improve articulation with increased angles, include heavy-duty bearings and are designed to the exact dimensions of the RTV. Fitment is the main concern for most buyers, but all aftermarket axle brands have done their homework here, regardless if you're going with Kubota 900 axles or types for heavier vehicles, such as the RTV-X1100C or its bigger 1120 and 1140 brothers. The icing on the cake is the much lower prices and, with branded variants, extended warranties for peace of mind.
Choosing From the Range of Aftermarket Options
Standard-duty aftermarket offerings are quite cheaper than OEM replacements but made to a higher standard. They're built in thicker diameters, so capable of more abuse, use high-grade steel in the shafts (less stress fatigue and higher strength), have industrial-grade bearings to cope with extreme temperatures, and boots feature puncture-resistant materials to stand up to the rigours of demanding everyday jobs.
Spend a little more and go with heavy-duty variants. These build on the high strength of standard axles and include even thicker solid shafts, but are made from high-strength and heat-treated 4340 Chromoly steel, use heavy-gauge neoprene for the boots (these run circles around thermoplastic factory types) with better abrasion and impact resistance, and use heat-treated bearings to reduce friction and ensure they last. Boots are also packed with high-load moly grease, further improving longevity. Parts are CNC-machined for utmost precision and undergo extensive testing. Lastly, look for ISO-certified units to get your money's worth.
Axles for any Kubota model are sold individually, but a good idea is to change both left and right units (front and/or rear) to ensure both get power to the wheels equally well. Packaged deals for all fours are even cheaper and a good choice if you're considering a lift kit or slapping on bigger tyres. When shopping for Kubota axles, make sure to specify your model and year to ensure you get what fits and works as advertised.