A design engineer's guide to selecting components for specialist vehicles

Owners of specialised vehicles frequently face challenges when sourcing components, as these parts are often vehicle-specific and unique to particular models or manufacturers (OEMs). Models of tractors, excavators, harvesters, and other such vehicles are sometimes discontinued, making it difficult to find parts which are no longer being produced. The accelerated development of vehicle technology and increasing production demands have made discontinued models more common, exacerbating the issue of sourcing parts. 

As their industries grow around them, project and procurement leaders in construction and agriculture don’t have time to scour their network for specific spare parts, if it leaves them behind on production. Conversely, it’s a big decision to invest in a new vehicle, which needs to be justified by ROI projections and might not be realistic right away. 

Essentra Account Manager for Construction and Agriculture, Trevor Gregory, explains how the industry's transition to alternative fuel sources is creating a complex parts ecosystem, particularly affecting older diesel models as newer electric options gain popularity in certain segments.

“The transition to electric vehicles in construction and agriculture is happening at different rates based on vehicle size. Smaller compact machines, such as those used by builders for landscaping, have adopted electric power more readily. This leaves some previous models – often diesel-powered – struggling for parts,” Trevor says. 

For owners of larger specialist vehicles, the transition to electric power has been more challenging. While these larger diesel models and their specialised parts remain available in the market, their owners are caught in a difficult position – they want the production efficiency that newer, electrified smaller vehicles offer, but aren't ready to replace their entire fleet. This creates a dual challenge in the industry: maintaining parts availability for existing larger vehicles while also supporting the transition to newer technologies, both of which ultimately depend on reliable access to specialised components.
The specialist vehicle market transition

Whether you're maintaining an old diesel engine or servicing a new hydrogen refuelling facility, specialised components are needed for both systems. However, industry trends strongly suggest that construction machinery powered by alternative fuel sources will become increasingly important in the coming years, with many major manufacturers already investing heavily in this area.

Several of the leading OEMs for construction machinery globally have already invested heavily in their own lines of electric vehicles, including Komatsu, Caterpillar, Hitachi, John Deere, and Volvo. The UK market is being shaped by the government's recent commitment to restore the 2030 phase-out date for new petrol and diesel cars and vans, with more than two-thirds of car manufacturers in the UK already committed to fully transitioning to electric cars by 2030. Research by Mordor Intelligence shows the UK construction equipment market is transitioning toward a net-zero carbon economy, with manufacturers actively introducing new zero-emission machines to meet market demands. 

The most significant barrier to greener vehicles in the UK remains infrastructure, as the transition to electric vehicles is considered "a crucial step towards achieving the UK's net zero target by 2050" by the House of Commons. Whether it's methane digesters, hydrogen refuelling facilities, or large battery cells, collaboration between the government, private sector, and innovators is needed to address the current gaps. The UK government is investing significantly to support this transition, with £2 billion allocated to support domestic manufacturers in transitioning to zero emission vehicles and over £300 million to drive consumer uptake.

Electric vehicles have a famously low cost of ownership over time thanks to reduced fuel and maintenance costs. This makes them particularly attractive as the UK pushes for more sustainable construction practices, with electric construction equipment now joining electric cars as eco-friendly alternatives. However, the initial outlay remains far greater than traditional diesel vehicles, creating financial planning challenges for UK construction and agricultural businesses. Experts expect the industry to reach a tipping point in the years to come, where the majority of heavy equipment will begin moving away from diesel engines to electric or hybrid solutions.

Component requirements

The good news is that core component requirements remain largely similar between traditional and alternative fuel vehicles. Many components such as cabs, seating, hydraulics and others concerning external functionality (forks, drills, buckets etc.) can be shared. In fact, farmers and construction workers may find themselves maintaining newly acquired vehicles using parts from old, traditional models. 

These core components fall into two categories: protective components used during manufacturing/transport and removed before final delivery; and components that remain on the finished vehicle.

Trevor says his work with specialist vehicles reveals a surprising level of crossover between old and new. 

“We talk a lot about the transition from traditional to alternatively-fuelled vehicles, but there’s no need to reinvent the wheel. It’s about putting a new power source in a chassis that’s tough enough for the farm or construction site. This may come with some new plugs, wiring and exhaust systems, but ultimately, we have the bulk of parts ready to repurpose as technology develops,” he says.

As Trevor states, the primary differences between traditional and alternative technologies centre around the power source – whether it be a battery, hydrogen engine, methane system or something completely different.

“In an ideal world, OEMs would collaborate to standardise these new parts so as to ease the burden on end users and their suppliers. However, this is not the case, and a need for specialist parts suppliers remains,” Trevor says. 

Design engineer challenges

A design engineer must work through a client's proposed applications, expectations and aims to offer custom solutions and support. While electric and alternative-fuel vehicles offer promising solutions for sustainability, they present their own engineering challenges.
As Trevor explains: "Battery life and power generation are the primary concerns. When you're dealing with machines weighing several tonnes that need to move significant amounts of raw material, the challenge is ensuring the battery can sustain that level of power requirement."

The best way to alleviate these issues is to hold meaningful conversations with the customer to understand their exact application. If an electric loader is ordered, for example, then it's important to ask about the target load cycles. What material and weight are they working with? What is the terrain? And where is the charging station located in relation to the worksite?

Trevor emphasises this collaborative approach. 

"We don't simply wait for clients to send specifications and ask us to manufacture. We prioritise understanding the full application context so we can discuss the optimal manufacturing approach. By knowing exactly what they expect from each component, we can establish a true partnership with our clients."

These are just a few preliminary questions that might be asked of a client, but their exact application will lend itself to greater specifics. Once these details are understood, a design engineer can deliver a far more accurate product that maximises its usefulness.

However, there are some obstacles that are harder to overcome. One example being long development cycles. New technology can be exciting for clients and engineers, but it can be a slow process to ensure the end product does exactly as promised. 

Trevor notes that volume production is another challenge for emerging technologies. 
"The initial production volume presents a significant hurdle. We need to set up machinery for efficient production, yet clients might only require very limited quantities initially. You're essentially developing products that may not reach full-scale production for years. In this emerging industry, patience is essential as we wait for adoption to accelerate."

Essentra's Value Proposition

When selecting an engineering team to deliver customised, specialty vehicle parts, it’s important to consider a handful of factors, such as a global presence that can support multinational OEMs locally. In hard-working industries like construction and agriculture, a globally present engineering team allows for faster turnaround times when every hour of lost production can cost thousands of dollars. 

A specialised engineering team should also have the expertise to collaborate directly with customer design teams. This real-time collaboration can facilitate meaningful discussion that leads to more accurate design briefs, removes unnecessary functionality, and maximises productivity. If an engineering team doesn’t work well with a client’s design team, these misalignments can materialise in the final design.

Large construction and agricultural companies can’t risk their partners folding mid-project, as many projects can take years to reach full production volume. A competent engineering team must embody longevity and scalability, with the warehousing capacity to work alongside a client’s business.

Fortunately, Essentra ticks all of these boxes, with years of experience delivering specialty vehicle designs and parts for clients across construction and agriculture. With Trevor playing a key part in the production of such parts for more than two decades, Essentra clients can remain confident in the quality of their final product.

“Using our experience across ConAg, automotive, electronics, heavy engineering, and oil and gas, our team finds the very best solution to each problem. We love to collaborate with clients and push the boundaries of engineering as technology develops. We’re excited by the rise of alternatively-fuelled vehicles, as they present a new challenge through which we can take these industries to greater productivity,” he says.