North American Heavy Truck, Bus and Off-Highway Foams and Acoustics: Supply Base and Application Map

A Class 8 sleeper cab is a small apartment. It has a seat the driver sits in for eleven hours, a mattress the driver sleeps on roughly 250 nights a year, a sofa or dinette that converts to a second bunk, and an insulation package whose job is to keep a 500 horsepower diesel out of the bedroom. Every one of those is a foam part, and together they represent more foam content per vehicle than anything on a passenger car assembly line.

That is the first of three markets in this report, and it is the one most suppliers already understand, because it looks like automotive seating with the numbers turned up. The duty cycle is what is different. A tractor seat has to hold its shape and its support through 300,000 to 1,000,000 miles of continuous vibration with a driver population that runs heavier and gets in and out a dozen times a shift. Molders answer with densities in the 3.0 to 4.0 lb range against the 2.2 to 2.8 lb of an automotive cushion. The mattress is a regulated product under 16 CFR 1633 and needs a fire barrier that survives a thirty minute open flame test. Neither of those is a detail a supplier can learn on the job.

The second market does not look like automotive at all. An off-highway operator cab on a tractor, excavator, loader, or dozer is an acoustic compliance problem. OSHA 29 CFR 1910.95 caps operator noise exposure at a 90 dBA eight-hour time-weighted average and requires a hearing conservation program above 85. ISO 6396 is the dynamic test the equipment maker runs to publish the number on the specification sheet. Foam and fiber are what close the gap between the machine as built and the number the sheet has to show. That makes acoustic content in an off-highway cab a compliance line item rather than a comfort feature, and compliance line items do not get value-engineered out in year three.

The third market is transit bus, and it is a Buy America market. Federal Transit Administration rules put a domestic content floor on any bus bought with federal money, FTA Docket 90A sets flammability and smoke limits well beyond FMVSS 302 for the interior, and the seat suppliers are a completely separate roster from the truck ones. Freedman Seating and American Seating own transit and school bus passenger seating. Neither name appears anywhere in the Class 8 conversation.

What ties the three together is that they are all small-program businesses. A heavy truck cab program builds tens of thousands of units a year, not hundreds of thousands. An off-highway cab program might build a few thousand. That kills the tooling amortization case that drives automotive material choices and it is why needled polyester felt, which thermoforms cheaply, holds so much of the acoustic content here against molded foam, which does not.

Twenty-five OEM sourcing organizations sit at the top of this industry: the Class 5-8 truck builders (PACCAR, Daimler Truck North America, Navistar, Volvo Trucks North America, Mack), the off-highway equipment makers (Deere, Caterpillar, CNH Industrial, AGCO, Kubota, Komatsu, Doosan Bobcat, Terex, JLG, Oshkosh), the bus builders (Blue Bird, New Flyer, Gillig, Thomas Built), and six trailer makers. They hold OEM position rows written once and read by every lens in this industry. What changes from lens to lens is which door the material comes in, and on this lens it comes in three different doors.

Cab seating and sleeper content goes through a cab interior Tier 1. Commercial Vehicle Group is the largest single foam buyer in North American Class 8, supplying driver and passenger seats under the National Seating and Bostrom brands along with sleeper mattresses, bunk systems, headliners, and interior trim. Grammer Americas sits beside it with air suspension seats and, through Toledo Molding and Die, the interior trim and duct work. Bergstrom supplies the HVAC and no-idle systems that make the sleeper usable with the engine off, and the duct insulation and sealing foam that go with them. Seats Incorporated and Isringhausen are the independent seating alternatives. All of them buy molded and cut foam from Woodbridge and FXI rather than making it.

Off-highway goes through the cab builder and the operator seat house. Crenlo builds complete ROPS and FOPS operator cabs for equipment OEMs, including the glazing, the headliner, the trim, and the acoustic package that makes the cab hit its published operator noise number. Sears Seating in Davenport and Milsco in Milwaukee are the two names on operator seating for agricultural, construction, and turf equipment, with Grammer on the larger cabs. A foam supplier selling into off-highway calls on Crenlo and Sears, not on Deere.

Bus is its own roster. Freedman Seating in Chicago and American Seating in Grand Rapids supply transit, paratransit, shuttle, and school bus passenger seating, and both are geared to Buy America content requirements on federally funded transit orders. The acoustic content behind the ceiling and under the floor goes to the same Tier 2 acoustic houses that serve truck.

Tier 2 is where the material actually gets made, and it splits into two groups that rarely compete. The acoustic systems houses (Autoneum, Adler Pelzer, Auria, UGN, Janesville Acoustics, Alkegen, Pritex) mold and needle fiber and foam into dash, floor, firewall, tunnel, and headliner parts. The foam producers and converters (Woodbridge, FXI, Sekisui Voltek, Armacell, Rogers Corporation, UFP Technologies, Foam Supplies) make the bun, the roll, and the die-cut part. Almost all of them arrived here from automotive, which is worth noting: the credentials transfer, and most of them have not pushed as hard into truck and off-highway as they could.

Tier 3 is the same short chemistry list that sits under every polyurethane market: MDI, TDI, and polyol from Dow, BASF, Covestro, Huntsman, and Wanhua, plus BASF Basotect melamine foam, which is the material behind nearly all the high-temperature absorber content in this report. None of them sells to a truck builder.

Distribution matters at the small end. Foam Supplies carries polyurethane systems, dispensing equipment, and technical service to cab builders and converters too small to buy a tanker, and Rogers Foam stocks and die-cuts for converters, upfitters, and prototype shops.

The twenty-five OEM organizations in this industry buy foam and acoustic material in three sharply different ways, and the split does not follow the org chart. It follows the vehicle.

The Class 8 truck builders are the seating and sleeper market. PACCAR (Kenworth, Peterbilt), Daimler Truck North America (Freightliner, Western Star), Navistar (International), Volvo Trucks North America, and Mack build the tractors that carry sleeper cabs, and a large sleeper is where the foam content concentrates: driver seat, passenger seat, mattress, sofa, headliner, dash insulator, floor insulator, engine tunnel cover, door acoustics. Daimler has the largest Class 8 volume in the market and its Cleveland and Mount Holly plants in North Carolina are the single biggest destination for this content. PACCAR sells quietness as a product attribute on the Kenworth T680 and Peterbilt 579, which means the acoustic package there is specified rather than value-engineered, and PACCAR's VOC and odor specifications are among the tightest in the industry.

The off-highway equipment makers are the acoustic compliance market. Deere, Caterpillar, CNH Industrial, AGCO, Kubota, Komatsu, Doosan Bobcat, Terex, and JLG all publish operator noise numbers, and all of them have to defend those numbers under OSHA 1910.95 exposure limits with ISO 6396 as the measurement method. Deere and Caterpillar run the largest cab programs and both specify acoustic content to a written internal standard. The compact equipment makers, Bobcat and Kubota in particular, build enormous unit volumes of small cabs where every dollar of acoustic content is fought over and where the cab is often bought complete from a specialist.

The bus builders are the Buy America market. New Flyer and Gillig build heavy-duty transit buses for federally funded procurements where domestic content, FTA Docket 90A flammability, and a published interior noise level are all part of the order. Blue Bird and Thomas Built build school buses, which are an FMVSS 302 and FMVSS 222 market rather than a Docket 90A one, and the difference in specification between a school bus seat cushion and a transit one is invisible to the eye and decisive on an order.

The vocational and specialty builders sit across all three. Oshkosh (Pierce fire apparatus, McNeilus refuse, Oshkosh Defense) buys seats that have to survive an environment no over-the-road tractor sees, and fire apparatus seating carries its own SCBA and restraint requirements. Terex and JLG put operators in cabs and baskets that live outdoors year round.

The trailer makers (Wabash, Great Dane, Utility Trailer, Hyundai Translead, Stoughton, Fontaine) are the smallest consumers on this lens. Their polyurethane content is real and large, but it is refrigerated trailer panel insulation, which belongs to the bonded-panel story on the polymers and adhesives lenses rather than to seating and acoustics. They appear in the roster because they are heavy-truck OEMs, not because they buy much of what this report maps.