Every truck show since 2020 has promised an imminent zero-emission revolution, and every parts distributor I know has sat through at least one board meeting asking whether the diesel parts business is about to evaporate. So let's deal with the real question head-on: what does the electric trucks spare parts aftermarket impact actually look like, and on what timeline? The honest answer is that it is profound in specific part families — and far slower across the whole vehicle parc than the headlines suggest.
Start with the numbers. In 2025, battery-electric trucks took roughly 2% of new heavy-truck registrations above 16 tonnes in the EU — 4,991 units out of about 254,500, according to ACEA data. Across all trucks above 3.5 tonnes, electrically-chargeable vehicles reached 4.2% of new registrations. Meanwhile, ACEA's vehicles-in-use figures show 96.3% of trucks on European roads still run on diesel, and the average EU truck is about 14 years old. In the United States, CALSTART counted zero-emission trucks at just over 4% of new deployments in the second half of 2025 — driven overwhelmingly by cargo vans, not Class 8 tractors.
Translation for anyone who buys, stocks, or fits truck parts: the diesel aftermarket has 15–20+ years of runway, and a new electric-parts segment is being built alongside it, not instead of it. This article maps which parts disappear with battery-electric trucks, which stay, which grow, what hydrogen changes, and what fleets and distributors should actually do about it.
Where Zero-Emission Trucks Actually Stand in 2026
The European picture is a story of two segments. Medium-duty trucks (3.5–16 tonnes) are electrifying fast in urban distribution: plug-in vehicles took roughly 14.8% of new medium-duty registrations in 2025, up 87% year on year per ACEA. Heavy long-haul tractors are a different animal — around 2% battery-electric on new registrations, concentrated in a handful of markets. Germany accounted for over 40% of all new EU electric truck registrations, and Switzerland leads Europe with battery-electric trucks taking nearly one in five new registrations above 3.5 tonnes, helped by its heavy-vehicle road-charging structure.
The United States is further behind on heavy tractors. CALSTART's cumulative count reached about 72,000 zero-emission trucks on US roads by the end of 2025 — against a national truck population in the tens of millions — and the growth is dominated by Class 2b–3 cargo vans. Hydrogen is barely measurable: CALSTART counted fewer than 200 heavy-duty fuel-cell trucks deployed across the entire country.
Hydrogen in general had a sobering couple of years. Nikola went through bankruptcy and liquidation in 2025. On the credible side, Hyundai's XCIENT fuel-cell trucks operate in 13 countries and have passed 20 million kilometers in Europe, and Daimler Truck's GenH2 is in second-phase customer trials, with a small-series run of about 100 trucks planned from late 2026 and full series production pushed back to the early 2030s. FCEV heavy trucks are real, but they are a 2030s volume story, not a today story.
The critical distinction for the parts business: new-vehicle share is not parc share. A 4% share of new registrations moves the total fleet composition by a fraction of a percent per year. The trucks that will fill workshop bays in 2035 are, overwhelmingly, diesels that are already on the road or will be registered in the next few years.
The Aftermarket Impact of Electric Trucks: Parts That Disappear
When a battery-electric truck replaces a diesel, an entire catalog chapter goes with it. On a per-vehicle basis, BEVs eliminate:
- Diesel engine internals: pistons, liners, crank and rod bearings, valvetrain, head gaskets, timing gear — and the machining and remanufacturing trades built around them.
- The complete fuel system: injectors, common-rail and unit pumps, fuel filters, lift pumps, tanks, and lines. Injector and fuel-filter sales are steady bread-and-butter revenue today.
- Air intake and turbocharging: turbochargers, intercoolers, air filters sized for combustion airflow.
- Exhaust aftertreatment, entirely: EGR valves and coolers, DPFs, SCR catalysts, AdBlue dosing systems, NOx sensors. Ironically this is one of the highest-failure, highest-margin categories on modern Euro VI diesels.
- Engine lubrication: engine oil, oil filters, and the service events they anchor.
- Most of the driveline: the clutch and multi-speed gearbox largely vanish; most e-axles use single- or dual-speed reduction gearing. Starters and alternators go too.
Two caveats stop this from being a simple subtraction. First, these parts disappear per BEV sold, and BEVs are a small slice of sales — total market demand for engine and aftertreatment parts declines only as fast as the diesel parc shrinks. Second, tightening emissions rules cut the other way in the near term: Euro 7 raises the durability and monitoring requirements on aftertreatment systems, which historically means more sensors, more sophisticated components, and more aftermarket repair opportunity on the diesels that keep selling.
Parts That Stay: Air Brakes Remain — With a Twist
Here is the part of the story that gets lost in the EV hype cycle: a 40-tonne combination still has to stop, and it still stops with compressed air. Battery-electric and hydrogen heavy trucks retain the full air brake system — brake chambers, disc calipers or slack adjusters, foundation brakes, air dryers, multi-circuit protection valves, and the trailer supply interface. The physics and the regulations governing heavy-vehicle braking do not care what spins the wheels.
What changes is the air source. With no engine to drive a gear-mounted compressor, BEVs use electrically driven compressors — self-contained units with their own motor and inverter, often oil-free scroll or piston designs running on demand rather than continuously. That is a genuinely new part family with its own service profile, and it is a natural evolution for established air-brake manufacturers. Suppliers like Vaden Original — an air brake specialist producing since 1968 with more than 12,000 OEM-compatible references — are working from exactly the compressed-air competence that zero-emission trucks continue to demand.
The other twist is regenerative braking. Regen handles most routine deceleration, so friction pads and discs on a BEV can last two or three times longer than on a comparable diesel. Good news for fleet cost-per-kilometer; a volume headwind for friction-parts sales per vehicle. But underused brakes develop their own pathology: corroded discs, glazed pads, and seized calipers from sitting idle. Friction-parts demand per truck falls; inspection and corrosion-related brake service does not.
Workshop tip: Do not extend brake inspection intervals on battery-electric trucks just because pad wear looks minimal. Check discs for corrosion scoring, confirm calipers slide freely, and exercise the foundation brakes under load periodically — a hard stop with regen limited will do it. And the air dryer cartridge still needs its scheduled change; the e-compressor works no drier than the old one.
Beyond braking, most of the truck is powertrain-agnostic and stays firmly in the catalog: suspension components and air springs (working harder under battery weight), steering parts, wheel hubs and bearings, kingpins, fifth wheels, cab suspension, mirrors and glazing, lighting, and effectively everything on the trailer.
Parts That Grow: Thermal Management Is the New Engine Bay
If aftertreatment was the growth category of the diesel decade, thermal management is the growth category of the electric one. A BEV truck does not have one cooling circuit; it has several — a tightly controlled loop keeping the battery in its temperature window, a separate loop for power electronics and motors, and a cabin system that can no longer scavenge free engine heat, so heat pumps and high-voltage PTC heaters take over.
That means electric coolant pumps, chillers, multi-way coolant valves, manifolds, specialized radiators, and coolant formulations — multiplying per vehicle rather than disappearing. The fundamentals of truck cooling system maintenance still apply, but the parts count and the diagnostic complexity go up. Add high-voltage cables, connectors, and contactors; DC-DC converters feeding the 24V system; and insulation-monitoring components. Tires deserve a mention too: heavier vehicles delivering instant torque wear them faster, which is one reason regulators are now scrutinizing tire and brake particulate emissions alongside exhaust.
Hydrogen Fuel Cell Trucks Keep Air Management Alive
Fuel-cell trucks are, from a parts perspective, electric trucks with a chemistry lab on board — and that chemistry lab breathes air. The fuel-cell stack needs a precisely managed cathode air supply, delivered by a high-speed electric air compressor, filtered to standards far stricter than any engine intake (stack membranes are easily poisoned by contaminants), and conditioned by humidifiers and recirculation hardware. For companies whose core competence is moving and treating compressed air, FCEVs keep that expertise commercially relevant in a way pure BEVs only partly do.
On top of the air side comes hydrogen storage and delivery: 350- or 700-bar composite tanks, pressure regulators, valves, and leak-detection systems — all with mandatory inspection regimes. And FCEV cooling systems are larger still than BEV ones, because fuel cells reject heat at a lower temperature differential, demanding oversized radiators and fans. The volumes remain tiny today, but every serious FCEV program on the road — XCIENT fleets, GenH2 trials — carries a full air brake system, an air-management stack, and a thermal system that dwarfs a diesel's.
Timeline Reality: The Diesel Parc Pays the Bills Into the 2040s
Run the arithmetic. The average EU truck is about 14 years old, and trucks in Greece average over 22 years. A diesel tractor registered in 2026 will realistically need parts into the 2040s — and diesels will dominate new registrations for several more years yet. Even under aggressive adoption scenarios, the parc turns over at single-digit percentages annually. The aftermarket serves the parc, not the auto show.
There is a second-order effect working in the independent aftermarket's favor: as diesel trucks age past warranty and first ownership, they migrate from franchised dealer networks to independent workshops, where aftermarket parts take a growing share of the repair spend. An aging diesel parc — exactly what the transition years produce — is historically the independent channel's best market. We covered this dynamic in detail in our aftermarket market trends analysis. There is even a plausible scenario where the final generations of diesel trucks are kept running longer than usual, the way operators held on to pre-DPF machines, stretching late-life parts demand further.
| Part family | Battery-electric truck | Hydrogen FCEV | Aftermarket outlook to 2035 |
|---|---|---|---|
| Engine internals, gaskets, oil system | Eliminated | Eliminated | Declines only with the diesel parc; strong late-life demand |
| Fuel injection and fuel filters | Eliminated | Replaced by H2 hardware | Stable near-term, slow decline from the 2030s |
| Exhaust aftertreatment (EGR, DPF, SCR) | Eliminated | Eliminated | Solid; aging Euro VI diesels consume more, Euro 7 adds content |
| Air brake system (chambers, dryers, valves) | Retained; e-compressor replaces gear-driven | Retained | Stable core plus a new e-compressor niche |
| Friction parts (pads, discs) | Retained; less wear, more corrosion service | Same as BEV | Volume per truck falls; parc size sustains totals |
| Clutch and multi-speed driveline | Mostly eliminated | Mostly eliminated | Declines with the diesel parc |
| Suspension, steering, wheel ends | Retained; higher axle loads | Retained | Stable to growing |
| Thermal management | Greatly expanded | Expanded even further | Fastest-growing category |
What Fleets and Parts Distributors Should Do Now
For fleet operators
- Keep diesel maintenance discipline. Your diesels are your revenue for the next decade. Preventive maintenance and quality parts sourcing matter more, not less, as the fleet ages.
- Pilot BEVs where the duty cycle genuinely fits — urban and regional return-to-base work — and treat the pilot as a maintenance-learning exercise, not just an energy-cost trial.
- Build high-voltage competence early. HV safety qualification takes time, and techs who can work on both diesel aftertreatment and 800V systems will be the scarcest resource in the industry. HV repairs beyond qualified scope belong with trained professionals — this is not a learn-on-the-job domain.
- Rewrite the BEV inspection sheet. Brakes on condition and corrosion rather than wear alone; coolant loops per manufacturer spec; air dryer service unchanged.
For parts distributors
- Deepen, don't abandon, diesel wear-parts coverage. The aging parc will consume aftertreatment, injection, and engine parts for 15–20 more years, increasingly through independent channels.
- Add zero-emission lines incrementally: e-compressors, thermal-management components, and HV-adjacent consumables as your customer fleets actually deploy vehicles — stock follows the parc, not the press release.
- Anchor on powertrain-agnostic categories. Braking, suspension, steering, and air management sell to every truck regardless of what powers it. Sourcing OEM-compatible air brake components from manufacturers with deep ranges keeps one supplier relationship relevant across diesel, BEV, and FCEV alike.
- Invest in identification capability. E-variants multiply part-number complexity; counter staff who can resolve VIN-level fitment will win the business.
The heavy-vehicle aftermarket has absorbed every powertrain evolution since the first diesel displaced gasoline engines from trucks — and it absorbed Euro VI, which gutted and rebuilt entire product categories. The zero-emission transition is bigger, but it is also slower than any previous one relative to the noise around it. Serve the diesel parc that exists, learn the electric truck that is coming, and keep your money in the parts that every truck needs no matter what fuels it. That is not hedging; that is reading the registration data.