Motor Vehicle Steering and Suspension Components (except Spring) Manufacturing — U.S. Industry Primer

NAICS 2022 code 336330. Figures below are the most recent U.S. federal statistics available; forward-looking statements are worded as judgments, not facts.

1. Overview

This industry makes the parts that let a vehicle turn and absorb the road: steering gears, columns, racks, power-steering units, shock absorbers, struts, control arms, ball joints, tie rods, and stabilizer (sway) bars — everything in the steering and suspension systems except springs, which are counted in a separate industry [1][2].

Why an investor should care: these are "wear-and-safety" parts that go into essentially every one of the ~289 million light vehicles on U.S. roads and wear out over time, so demand has two legs — new-vehicle production and replacement (aftermarket) [12]. The category is also powertrain-agnostic: a car needs steering and suspension whether it burns gasoline or runs on a battery, which makes it a relative safe harbor in the electric-vehicle (EV) transition compared with engine-parts suppliers. On top of that, the dollar value of steering per vehicle is rising as the industry shifts from old hydraulic power steering to electric power steering (EPS) and, increasingly, steer-by-wire — the electric hardware that advanced driver-assistance systems (ADAS) need to steer the car themselves [10].

The catch for public-market investors: there is no large, pure-play, U.S.-listed company in this business. The leaders are foreign-owned Tier 1 suppliers, a Chinese-state-controlled company, and private-equity-owned firms. Public and private ways in are covered in Sections 4 and 10.

2. What it is and how it's structured

Scope (what's inside 336330). Establishments that manufacture or rebuild motor-vehicle steering mechanisms and suspension components: steering columns, steering wheels, steering gears and boxes, rack-and-pinion assemblies, power-steering pumps and EPS units, shock absorbers and struts, control arms, ball joints, tie rods, kingpins, and stabilizer bars [1][2].

Physical production. The manufacturing process ranges from metal forming, casting, and precision machining through heat treatment, coating, gear cutting, sealing, electronics integration, and final assembly. A conventional rack or steering gear combines housings, shafts, bearings, gears, and either hydraulic or electric assist; electric power steering adds motors, torque and position sensors, control electronics, and software. Shock absorbers and struts combine tubes, piston rods, seals, valves, and hydraulic fluid — their essential job is restricting spring oscillation, and the industry is moving toward electronically controlled, continuously adjustable damping and redundant-motor steer-by-wire architectures [15].

What it explicitly excludes (and where those parts are counted instead):

• Springs — leaf, coil, and torsion springs — are in NAICS 33261 / 332613, Spring Manufacturing. This is why the industry name carries the "(except Spring)" tag [1][2].
• Brakes → NAICS 336340 (brake systems).
• Transmission and driveline / powertrain parts (axles, drive shafts, CV joints) → NAICS 336350.
• Engine and engine parts → NAICS 336310.
• Electrical/electronic equipment → NAICS 336320.
• Anything not captured above → NAICS 336390 (other motor-vehicle parts).

This matters when reading company financials: firms like American Axle and Dana are usually described as chassis or suspension names, but most of their revenue is really driveline (336350), with only partial steering/suspension content.

Commercial model. The industry is mostly platform-based Tier 1 supply. Suppliers engineer a part or system for a vehicle program, invest in tooling and validation, then ship in sequence to assembly plants. Orders usually cover a customer's requirements for a model life rather than a guaranteed unit quantity, leaving the supplier exposed to the automaker's actual production mix and to cancellations after development spending has begun. Customers also demand annual price reductions over a model's life, forcing manufacturing and design cost-downs simply to hold margin [16].

Ownership mix. This is a Tier 1 / Tier 2 manufacturing industry — mid-size to large plants supplying automakers (original-equipment, or OE) and replacement-parts distributors (aftermarket). It is not dominated by tiny owner-operators or by government, so federal business statistics capture it well (see Section 3 for the one real caveat). Ownership is unusually international: much of the U.S. steering-and-suspension footprint belongs to German, Japanese, Korean, and Chinese parents, and two of the biggest players (Tenneco, Marelli) are owned by private-equity firms.

3. How big it is (U.S. federal figures)

From the most recent official data:

For scale, receipts were about $15.8 billion in 2017, so the industry grew modestly over five years [4]. Average pay works out to roughly $62,000 per worker (payroll ÷ employment) — typical of skilled U.S. manufacturing.

The undercount caveat here is not about tiny operators — it's about imports. These 267 U.S. plants make about $17 billion of product, but the United States installs far more steering and suspension content than that: imports of these parts have run higher than the domestic figure, and the country is a net importer [4]. So the federal statistics reliably measure U.S. production, but they understate the size of the market Americans actually buy into, because a large share of the steering racks, shocks, and control arms on U.S. vehicles are made abroad. Read $17 billion as the domestic manufacturing base, not total demand.

Concentration. By the standard federal yardstick the industry looks unconcentrated: the Herfindahl-Hirschman Index (HHI, a market-concentration score where below 1,500 is "unconcentrated") is just 487 [3]. The top four firms account for 34.5% of revenue, the top eight for 54.6%, the top twenty for 76%, and the top fifty for 91.9% [3]. That long tail is real — hundreds of specialist shops make specific parts. But within any single OE product line (say, electric steering racks for a truck platform), the practical competitive set is a handful of global Tier 1s, so the headline HHI understates how concentrated any one automaker's supplier choice really is.

4. The investable universe

There is no large U.S.-listed pure play. A general investor gets exposure three ways: (a) diversified U.S. suppliers that carry partial steering/suspension content, (b) U.S.-listed aftermarket names, and (c) foreign-listed or privately held Tier 1 leaders.

U.S.-listed suppliers with steering/suspension exposure (note: mostly driveline, chassis is a slice):

Foreign-listed / foreign-parent Tier 1 leaders (these actually dominate OE steering and suspension, including large U.S. plants):

Private / private-equity-owned:

• Tenneco — owner of the Monroe shocks-and-struts brand and the DRiV aftermarket platform; taken private by Apollo Global Management in a ~$7.1 billion deal completed November 2022 [4].
• Marelli — owned by KKR (private).

5. How the money works

Steering and suspension makers earn money the way most auto Tier 1s do — the economics that matter are program awards, content per vehicle, capacity utilization, and the two-channel (OE + aftermarket) split, not store counts or occupancy.

• Program-based revenue. A supplier wins a "platform award" to supply a part for the life of a vehicle program — typically 5–7 years. Up-front tooling and engineering are heavy; profit comes as volumes ramp and fixed costs get spread. Bookings not yet in production are reported as backlog and are the key forward indicator.
• Content per vehicle (CPV). The single most important growth lever. Old hydraulic power steering is being replaced by electric power steering, and premium/EV models add adaptive dampers, air suspension, and eventually steer-by-wire — each raising the dollars of this industry's content on a given car even if total vehicle production is flat [10]. Heavier EVs (big batteries) also load the suspension more, nudging content up.
• Capacity utilization and operating leverage. Stamping, forging, and machining lines are high-fixed-cost. When plants run full, margins expand fast; when automaker build rates drop, fixed costs bite and margins compress. Volumes track OEM production schedules (just-in-time), not retail sales directly.
• Raw-material pass-through. Steel and aluminum are the main inputs. Contracts usually pass material costs through to automakers, but with a lag, so a sudden steel spike squeezes margins for a quarter or two. Other variable inputs include electric motors, magnets, bearings, sensors, semiconductors, seals, and hydraulic fluids [16].
• Two channels with opposite cycles. OE sales are high-volume, lower-margin, and cyclical with new-car production. Aftermarket (replacement) sales are higher-margin and counter-cyclical — when new-car sales fall, people keep older cars longer and repair them. Steering and suspension parts are genuine wear items, so the aftermarket is a steady ballast.
• Thin margins, capital intensity, leverage. Reported EBITDA margins in this space typically run mid-single to low-double digits; net margins are slim. For illustration, Nexteer — a steering-focused Tier 1 — reported an 11.4% gross margin, roughly 10% adjusted EBITDA margin, and a 2.2% net margin in 2025, with raw materials consuming about 65% of revenue [16]. Balance sheets are often levered (especially the PE-owned names), so free cash flow and debt paydown are watched as closely as growth. Automakers also demand annual price reductions ("price-downs"), a permanent drag suppliers must offset with cost cuts [16].

6. What drives demand

• Light-vehicle production (the cycle). OE volume follows automaker build rates. U.S./North American output topped 16.06 million units in 2024, but 2025 was tracking lower — roughly 15.3–15.6 million — a reminder that the OE side is cyclical [11]. Regional mix can diverge from global trends: global OEM output rose 3.7% in 2025 while North American production fell 1.0% [16].
• Content growth (the structural tailwind). EPS penetration in North American new vehicles already exceeds ~70% and is still rising; over 85% of battery-electric vehicles use electric steering; steer-by-wire and ADAS steering functions add electronics and redundancy — all of which lift this industry's revenue per car [10]. The U.S. electric-power-steering market alone was about $5.5 billion in 2024 and is projected to grow at a mid-single-digit rate [9].
• Fleet size and age (the aftermarket). The U.S. light-vehicle fleet reached 289 million vehicles at an average age of 12.8 years in 2025 — a record [12]. Older vehicles need more suspension and steering repairs, and the large 2015–2019 model-year cohort is now entering its heavy-repair window, supporting replacement demand [12].
• Vehicle mix. Trucks and SUVs carry more (and larger) steering/suspension content than small cars, so a mix shift toward light trucks is a content positive.
• Miles driven and road conditions. More miles and rougher roads accelerate wear, feeding aftermarket volume.

7. Regulation

• Vehicle safety (NHTSA / FMVSS). The National Highway Traffic Safety Administration (NHTSA) writes and enforces Federal Motor Vehicle Safety Standards (FMVSS). Steering systems fall under standards governing steering-column rearward displacement and energy absorption in a crash (FMVSS 203 and 204), and electronic-stability-control requirements (FMVSS 126) that interact with steering inputs [14][19]. Because a steering or suspension failure can cause loss of vehicle control, defects here trigger high-severity safety recalls — a real financial and reputational risk for suppliers [14]. These are performance requirements, not mandates for one steering design, which matters as steer-by-wire proliferates [19].
• Product liability and warranty. These are safety-critical parts; warranty and liability exposure is meaningful, and quality problems can cost a supplier a program. Nexteer, for example, carried $84.1 million of estimated warranty and product-liability provisions at year-end 2025 [16].
• Trade policy. In 2025 the U.S. applied Section 232 tariffs of 25% on imported automobiles and certain auto parts [13]. Because the industry is a net importer of steering and suspension components and its supply chains cross the U.S.–Mexico–Canada border, tariffs and USMCA regional-content rules directly affect costs and sourcing decisions [13]. USMCA requires 75% regional value content for qualifying passenger vehicles and light trucks, treats steering and suspension as core parts, and imposes North American steel and aluminum sourcing requirements [20].
• Indirect drivers. Fuel-economy (CAFE) and emissions rules push automakers toward lighter vehicles, which nudges suppliers toward aluminum and lightweight designs in control arms and knuckles.

8. Competitive dynamics and consolidation

At the establishment level the industry has a long tail of specialists (HHI 487, top-four share 34.5%) [3], but OE steering and suspension are effectively an oligopoly of global Tier 1s — Bosch, ZF, JTEKT, NSK, thyssenkrupp, Nexteer, Hitachi Astemo, KYB, and HL Mando — that compete for a limited number of automaker platform awards [10]. Bargaining power sits heavily with the automaker customers, who are few and demand annual price cuts. Customer concentration can be severe: General Motors and affiliates represented 34% of Nexteer's 2025 revenue, illustrating the risk created by platform awards [16].

Consolidation is the dominant theme:

• Apollo took Tenneco private (Monroe/DRiV) in 2022 and has roughly doubled its EBITDA, with an eventual IPO discussed [4].
• American Axle combined with Dowlais (GKN) in a ~$1.4 billion deal (closed February 2026), creating a ~$12 billion driveline-and-metal-forming group [5].
• Dana sold its off-highway business to Allison for $2.7 billion (2026) to concentrate on light and commercial vehicles [6].
• On the aftermarket side, Standard Motor Products bought Nissens (2024) and distribution consolidators continue to roll up parts supply [8].

Chinese ownership and Chinese entrants are a live competitive and political factor — Nexteer, a leading U.S.-operating steering supplier, is majority-controlled by a Chinese state group [9].

9. Risks

• Cyclicality. OE volume rises and falls with auto production; a downturn hits utilization and margins hard.
• Customer concentration and pricing pressure. A handful of automakers control the awards and impose annual price-downs; suppliers absorb the squeeze.
• Input-cost and labor inflation. Steel/aluminum spikes and wage pressure hit margins before pass-throughs catch up.
• Tariffs and trade disruption. The 25% Section 232 parts tariff and cross-border supply chains create cost and sourcing uncertainty [13].
• Recall / product liability. Safety-critical parts carry outsized recall and litigation exposure [14].
• Cyber and software risk. As mechanical systems become electronically controlled, software and IT failures can cause production stoppages, data compromise, or manipulation — an emerging risk for suppliers of EPS and steer-by-wire [16].
• Leverage. Several major players are private-equity-owned and carry significant debt, raising sensitivity to a downturn or higher rates [4].
• Foreign competition / import penetration. Domestic makers compete against lower-cost imports that already supply a large share of U.S. demand [4].
• Supply-chain concentration. Sole-source electronics or forging suppliers, plus environmental compliance for plating, coatings, heat treatment, and fluids, create additional operational risk [16].
• Footprint rationalization. Labor arbitrage drives production shifts; Nexteer, for example, disclosed moving columns and intermediate-shaft work from its U.S. site to Mexico as part of a profitability program [16].
• The EV transition — mostly a tailwind, but not risk-free. Steering and suspension survive the shift to electric drivetrains (a big advantage over engine-parts peers), but the move to EPS and steer-by-wire demands electronics and software capabilities that favor scaled, well-capitalized suppliers and could strand laggards.

10. How to invest and the outlook

Public-market routes. Because there is no U.S.-listed pure play, exposure comes indirectly:

• Diversified U.S. suppliers — Dana (DAN) and American Axle/Dauch (AXL) — give partial chassis/suspension content inside a mostly-driveline business; both are cyclical and levered [5][6].
• Aftermarket names — Dorman (DORM), Standard Motor Products (SMP), MotorCar Parts of America (MPAA) — offer the steadier replacement-demand side, tied to the aging fleet rather than new-car build rates [7][8][12].
• Foreign-listed Tier 1 leaders — Nexteer (Hong Kong), JTEKT / NSK / KYB (Japan), thyssenkrupp (Germany), HL Mando (Korea) — are the way to own the OE steering/suspension leaders directly, with the added currency and governance considerations of foreign shares [9][10].
• Baskets — broad auto-parts or auto-supplier ETFs spread the cyclicality across many names.

Private-market routes. Private ownership is arguably the primary model in this industry. Private equity already controls Tenneco (Apollo) and Marelli (KKR), so large-cap buyouts are a demonstrated path [4]. Middle-market machining and forging shops that act as Tier 2/Tier 3 component makers are frequent acquisition and roll-up targets; private credit funds lend to the levered Tier 1s; and aftermarket distribution roll-ups continue. Diligence should separate OEM and aftermarket revenue, measure platform and customer concentration, identify customer-owned versus supplier-owned tooling, test commodity pass-through clauses, quantify warranty history, and examine whether capitalized engineering will be recovered if programs are delayed or cancelled [16].

Outlook (forward-looking judgment). The central tension is flat-to-lower unit volumes against rising content per vehicle. Near-term, softer 2025–26 North American build rates (~15.3–15.6 million versus 16.06 million in 2024) and the 25% Section 232 parts tariff are headwinds to volume and margin [11][13]. Structurally, the shift to electric power steering (already >70% of North American new vehicles), steer-by-wire, and adaptive suspension should keep lifting the dollars of this industry's content per car regardless of powertrain [10]. The record 12.8-year fleet age underpins a durable aftermarket floor [12]. And unlike engine-parts suppliers, this category is largely insulated from the EV transition — a car always needs to steer and to soak up the road. The likely winners are scaled suppliers that can fund the electronics and software content; the likely losers are sub-scale, hydraulic-era shops.

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Sources

1. U.S. Census Bureau, "North American Industry Classification System — 336330," 2022. https://www.census.gov/naics/?input=336330
2. NAICS Association, "NAICS Code 336330 — Motor Vehicle Steering and Suspension Components (except Spring) Manufacturing," 2024. https://www.naics.com/naics-code-description/?code=336330
3. U.S. Census Bureau, County Business Patterns 2023 and 2022 Economic Census (Comparative Statistics / Concentration), NAICS 336330. https://data.census.gov
4. Apollo Global Management, "Apollo Funds Complete Acquisition of Tenneco," 2022; and industry trade/receipts references. https://www.apollo.com/insights-news/pressreleases/2022/11/apollo-funds-complete-acquisition-of-tenneco-134627289
5. American Axle & Manufacturing, "AAM Announces Combination with Dowlais for $1.44 Billion in Cash and Stock," 2025; combination completed Feb 2026. https://www.aam.com/media/story/aam-announces-combination-with-dowlais
6. Dana Incorporated, "Full-Year 2024 Financial Results" and "Dana Completes Sale of Off-Highway Business," 2024–2026. https://www.dana.com/newsroom/press-releases/dana-incorporated-completes-sale-of-off-highway-business/
7. Forbes / Yahoo Finance, "Dorman Products (DORM) — Company Overview," 2026. https://finance.yahoo.com/quote/DORM/
8. Standard Motor Products, "SMP Completes Acquisition of European Aftermarket Supplier Nissens Automotive," 2024. https://www.prnewswire.com/news-releases/standard-motor-products-inc-completes-acquisition-of-european-aftermarket-supplier-nissens-automotive-302293368.html
9. Expert Market Research, "United States Electric Power Steering Market" (US EPS market ~$5.51B, 2024); Nexteer profile. https://www.expertmarketresearch.com/reports/united-states-electric-power-steering-market
10. Fortune Business Insights / Future Market Insights / IndexBox, "Automotive Electric Power Steering and Steer-by-Wire Market," 2025. https://www.fortunebusinessinsights.com/automotive-electric-power-steering-market-105808
11. S&P Global Mobility, "2025 Light Vehicle Production Forecast," 2025. https://www.spglobal.com/automotive-insights/en/blogs/2025-light-vehicle-production-forecast
12. S&P Global Mobility, "U.S. Vehicle Age Rises Again to 12.8 Years in 2025," 2025. https://press.spglobal.com/2025-05-21-U-S-Vehicle-Age-Rises-Again-to-12-8-Years-in-2025,-According-to-S-P-Global-Mobility
13. U.S. Customs and Border Protection, "Section 232 Additional FAQs — Automobiles and Auto Parts," 2025. https://www.cbp.gov/trade/programs-administration/entry-summary/section-232-additional-faqs-autos
14. National Highway Traffic Safety Administration, "Laws, Regulations & FMVSS," 2025. https://www.nhtsa.gov/laws-regulations
15. KYB Corporation, "Automotive Products," 2025. https://www.kyb.co.jp/en/products/automotive.html
16. Nexteer Automotive Group Limited, 2025 Annual Report, Hong Kong Stock Exchange. https://www1.hkexnews.hk/listedco/listconews/sehk/2026/0424/2026042402166.pdf
17. JTEKT Corporation, "Steering Systems," 2025. https://www.jtekt.co.jp/e/sustainability/governance/intellectualpropertyactivities/
18. HL Mando, "Rack Electric Power Steering (R-EPS)" and "Redundant Architecture Steering," 2025. https://www.hlmando.com/en/solution/chassis/steering/electric-power/r-eps.do
19. National Highway Traffic Safety Administration, "NHTSA Interpretation 1982-326 (Steering Systems)," 1982. https://www.nhtsa.gov/interpretations/1982-326
20. Office of the United States Trade Representative, "USMCA Economic Impact Report," 2019. https://ustr.gov/sites/default/files/files/agreements/FTA/USMCA/USMCA%20EIR.pdf