Nylon vs UHMW Polyethylene: Which to Choose?

Nylon and UHMW polyethylene (UHMW-PE) are the two most common engineering plastics for sliding, bearing, and wear applications, but they approach the problem from opposite directions. Nylon is stronger, stiffer, and handles a wider temperature range — making it the structural choice for gears, bushings, and load-bearing guides. UHMW-PE offers a lower coefficient of friction, superior abrasion resistance, and FDA food-contact compliance in a material that stays tough even at sub-zero temperatures. The right choice depends on load, speed, temperature, chemical environment, and whether you need regulatory compliance.

TL;DR

• Nylon (cast or extruded 6 or 6/6) has higher tensile strength (12,000–14,000 psi) and stiffness than UHMW.
• UHMW has one of the lowest coefficients of friction of any plastic (0.10–0.20 dynamic) and outlasts nylon in abrasion testing by 3–5×.
• Nylon absorbs moisture (1–3%), which can swell dimensions; UHMW absorbs essentially zero.
• UHMW is FDA 21 CFR compliant for direct food contact; nylon requires specific FDA-grade formulations.
• Nylon handles continuous service to 220–250°F; UHMW is limited to ~180–200°F continuous.
• UHMW is tougher and more impact-resistant at cryogenic temperatures (rated to -100°F and below).
• Nylon machines more precisely; UHMW is waxy, difficult to thread, and resists adhesives.

When to Choose Nylon

Structural Gears, Sprockets, and Rollers

Nylon's combination of strength, stiffness, and good fatigue resistance makes it the first choice for plastic gears, sprockets, and rollers that carry meaningful mechanical loads. Its tensile strength of 12,000–14,000 psi and compressive strength of 12,000–18,000 psi support tooth-loading scenarios that would cause UHMW to cold-flow. Oil-filled and MoS₂-filled nylon grades further reduce internal friction and extend wear life in geared applications.

Precision Machined Bushings and Bearings

Nylon machines to tighter dimensional tolerances than UHMW, holds threads, and can be bored to consistent inside diameters. For bushings where bore tolerance is critical — particularly where light press-fit or slip-fit dimensions must be held after installation — nylon gives more predictable results. Bear in mind that moisture absorption will cause dimensional growth of roughly 0.005–0.010 in/in in humid service environments; cast nylon or oil-filled grades reduce this effect.

Higher-Temperature Dry Running

When operating temperatures exceed 200°F continuously, nylon remains serviceable while UHMW approaches its upper limit. Nylon 6 handles up to about 220°F continuous; nylon 6/6 pushes to 250°F. For hot conveyor guides, oven-adjacent components, or machine parts near heat sources, nylon is the safer choice.

Self-Lubricating Components

Oil-filled, MoS₂-filled, and glass-filled nylon grades are widely available and convert nylon into a bearing-quality material with PV limits competitive with bronze bushings. These filled grades are standard stock at most distributors.

When to Choose UHMW

High-Wear Liner and Wear Surface Applications

UHMW's abrasion resistance is the highest of any thermoplastic by ASTM D4020 testing — typically 3–5× better than nylon in dry sliding against metal or abrasive materials. Hopper liners, chute liners, conveyor wear strips, and truck bed liners are almost universally specified in UHMW. The material resists gouging and abrasion from bulk solids, coal, grain, gravel, and ore with minimal wear rates.

FDA Food-Contact and Pharmaceutical Applications

Standard UHMW sheet and rod are FDA 21 CFR §177.1520 compliant out of the catalog, with no special grade required. Cutting boards, food processing guides, star wheels, and packaging machine components that contact food are commonly machined from UHMW. Its non-stick surface also discourages bacterial adhesion and cleans easily.

Low-Temperature Environments

UHMW remains tough and ductile to -100°F and below — a range where nylon becomes brittle and can crack under impact. Freezer conveyor guides, cryogenic equipment components, and cold-storage racking pads are typical UHMW applications.

Low-Friction Sliding and Guide Rails

When the design goal is minimum friction against metal rails or mating surfaces without external lubrication, UHMW's dynamic coefficient of friction (0.10–0.20) beats nylon (0.20–0.35). Sliding gates, plow shoes, dock bumpers, and chain guides in dry service use UHMW for this reason.

Specs Head-to-Head

Mechanical Properties

Nylon has roughly twice the tensile strength and three to four times the flexural modulus of UHMW. This makes nylon the structural engineering plastic and UHMW the wear-surface material. UHMW will cold-flow (creep) under sustained compressive loads at elevated temperatures; nylon is more creep-resistant. UHMW, however, is virtually impossible to break in impact testing — it consistently exceeds ASTM D256 notched Izod test capacity ("no break").

Friction and Wear

UHMW's molecular weight of 3–6 million g/mol produces a low-energy surface that resists abrasion and wet or dry friction. Nylon has a higher surface energy and, while it runs well against metal, does not match UHMW in abrasion-intensive applications. In mixed scenarios — moderate load, moderate wear — oil-filled nylon narrows the gap.

Moisture and Dimensional Stability

UHMW absorbs essentially no moisture; its dimensions are stable in wet, humid, and immersed service. Nylon absorbs 1–3% moisture depending on grade and ambient humidity, which causes dimensional swelling. For close-tolerance precision parts in variable humidity, this is a significant factor. Cast nylon and cast nylon with oil filling absorb somewhat less than extruded grades.

Chemical Resistance

UHMW has outstanding resistance to virtually all dilute and concentrated acids, alkalis, and solvents, including hydrochloric acid, caustic soda, and most organic solvents. Nylon is attacked by strong mineral acids (hydrochloric, sulfuric) and some polar solvents, though it resists alkalis, oils, and fuels well. In harsh chemical environments, UHMW is usually the safer choice.

Machinability

Nylon is the easier material to machine to precision tolerances. It cuts cleanly, holds threads well, and can be drilled and tapped without the gummy behavior that makes UHMW threading difficult. UHMW has a waxy, low-energy surface that resists adhesives and coatings; bonding UHMW parts requires special surface treatment or mechanical fastening.

Cost & Availability

Nylon and UHMW are similarly priced on a per-pound basis — typically in the $2–5/lb range in standard rod and sheet stock depending on size and grade. UHMW's lower density (0.93 g/cc vs 1.13 g/cc) means that for equal-volume parts, UHMW costs about 18% less by weight. Both materials are commodity stocks available in a wide range of sheet, rod, tube, and strip sizes. Specialty grades — oil-filled, glass-filled, anti-static, and food-grade variants — are available in both materials.

For wear strip, conveyor guide, and liner applications, UHMW is also available in extruded profile shapes and custom widths on a continuous basis, which can significantly reduce machining cost compared to cutting strips from flat sheet. Nylon is less commonly stocked in extruded wear-strip profile form; it is more often machined from rod or sheet into the required shape.

Lead times are short for both materials in standard sizes. Cast nylon rod is available in larger diameters (up to 16" and larger from some suppliers) than extruded nylon, making it the only practical option for large gear blanks and large-diameter bushings. UHMW rod is typically available through 10–12" diameter from stock; larger sizes may require order.

Both materials can be purchased with material certifications (FDA, RoHS, material conformance) at no significant premium. For food-processing applications requiring documentation, confirm the specific grade and lot certification with your distributor at the time of order.

Common Alternatives

• Acetal (Delrin) — Stiffer than nylon, lower moisture absorption, excellent machinability and dimensional stability. For precision bushings and gears where nylon's moisture sensitivity is problematic, acetal is often a better fit. See the nylon vs acetal comparison for details.
• PTFE — Lower friction than UHMW (0.04–0.10 dynamic COF) but much higher cost, lower strength, and worse abrasion resistance. PTFE-filled UHMW and nylon grades capture some of PTFE's friction benefit at much lower cost.
• HDPE — Related to UHMW but lower molecular weight, lower cost, and lower abrasion resistance. Suitable for general wear parts and tank/chute applications where UHMW performance isn't required. See the HDPE vs UHMW comparison for guidance.

More related guides

Explore related material decisions and where these plastics show up in real production:

Applications

• Bushings Bearings
• Wear Strips Guide Rails
• Gears

Industries

• Food Beverage
• Automotive

Other comparisons

• Uhmw Vs. Hdpe
• Uhmw Vs. Polypropylene
• Uhmw Vs. Ptfe Teflon

Spec sheets

• Nylon hub
• UHMW hub