Why Apitong? Selecting the Right Species for Your Trailer Deck

Trailer manufacturers have used a wide range of species over the years to deck flatbeds, lowboys and other platform trailers. Before choosing a species for a wood floor, it helps to understand that wood varies significantly by species, and the mechanical and physical properties of a particular species will determine how it performs.

During the 1960s, North American hardwood lumber (primarily oak, ash, beech, hickory and hard maple) was used extensively throughout the trailer industry. However, concern arose that domestic lumber from temperate forests was not strong enough to withstand the rigors of a platform trailer because of the weakness associated with knots and other defects. Getting trailer-grade flooring planks out of domestic lumber required careful selection to eliminate those defects, usually by trimming boards or ripping them into narrow planks, which typically produced narrow, short pieces of 5' to 9'. Domestic hardwoods also have limited durability in exterior applications, so chemical treatment is necessary.

Some of these shortcomings were addressed when trailer manufacturers began using tropical hardwoods such as Apitong in the early 1970s. Because tropical climates have relatively consistent temperatures, the seasonal swings in tree growth are mitigated, and tropical species grow at a steadier rate than those in temperate climates. Growth rings in tropical species are usually far more subtle, and the grain tends to be consistently tight throughout the tree. The result is strong lumber with fewer defects. Lumber cut from these trees averages 12' to 14' in length, which eliminates multiple short pieces when assembling a trailer deck.

Strength and Durability of Typical Trailer Flooring Woods

Here is how the species used in the trailer flooring industry compare. Modulus of rupture is bending strength, modulus of elasticity is stiffness, and side hardness is resistance to denting.

• Purpleheart: 4,800 lbs per MBF at 10% MC, 21,300 psi modulus of rupture, 2,420,000 psi modulus of elasticity, 11,380 psi crushing strength, 2,060 lbs side hardness, 1,830 psi shear.
• Apitong: 4,600 lbs per MBF, 19,900 psi modulus of rupture, 2,070,000 psi modulus of elasticity, 10,500 psi crushing strength, 1,270 lbs side hardness, 2,070 psi shear.
• Angelim Pedra: 4,400 lbs per MBF, 17,600 psi modulus of rupture, 2,050,000 psi modulus of elasticity, 8,990 psi crushing strength, 1,720 lbs side hardness, 2,010 psi shear.
• White Oak: 4,200 lbs per MBF, 15,200 psi modulus of rupture, 1,780,000 psi modulus of elasticity, 7,440 psi crushing strength, 1,360 lbs side hardness, 1,360 psi shear.
• Red Oak: 3,900 lbs per MBF, 14,300 psi modulus of rupture, 1,820,000 psi modulus of elasticity, 6,760 psi crushing strength, 1,070 lbs side hardness, 1,780 psi shear.
• Southern Yellow Pine: 3,100 lbs per MBF, 14,200 psi modulus of rupture, 1,880,000 psi modulus of elasticity, 7,750 psi crushing strength, 750 lbs side hardness, 1,490 psi shear.
• Douglas Fir: 2,700 lbs per MBF, 12,400 psi modulus of rupture, 1,950,000 psi modulus of elasticity, 7,230 psi crushing strength, 710 lbs side hardness, 1,130 psi shear.

Sources: US Department of Agriculture Handbook No. 207; US Department of Agriculture Handbook No. 72, pp. 4-24.

Besides having the best strength-to-weight ratio of any species commercially used for trailer decks, Apitong (also known as Keruing) contains a natural oleo-resin and a silica content of generally about 0.5%, both of which help the wood endure the outdoor elements. Other species used for their superior durability include Angelim Pedra (Parangelim) and Purpleheart. For a side-by-side look at the two most popular choices, see Apitong vs. Angelim Pedra.

With over 100 years of combined industry experience, TrailerDecking.com can help you choose the right species for your trailer. We work closely with original equipment manufacturers, aftermarket repair shops, hardwood lumber distributors, fleet owners and independent owner-operators. All segments of the transportation industry rely on our knowledgeable staff for both original equipment and replacement parts. Contact us with your trailer's details.