AT-Profile Timing Belts (AT3, AT5, AT8, AT10, AT15, AT20)
AT-profile timing belts are the high-performance evolution of the European T-profile system. The "AT" stands for Advanced Trapezoidal. AT-profile belts feature a modified tooth design with a wider base and optimized root geometry that distributes stress more evenly across the tooth, significantly increasing load capacity and reducing the risk of tooth shear compared to standard T-profile belts at the same pitch.
The AT-profile family spans six pitches from 3mm to 20mm, covering applications from compact precision servo drives to the largest industrial gantry systems. AT-profile belts are manufactured exclusively from polyurethane with steel wire or Kevlar tensile cords, and are available in both closed-loop and open-end (continuous roll) form. Open-end AT-profile belts with steel cord are the industry standard for European-designed heavy linear motion systems. Texas Belting stocks AT-profile timing belts across all six pitches.
Tooth form: Modified trapezoidal (wider base, optimized root geometry)
Standard: European (evolution of DIN T-profile)
Pitches: AT3 (3mm), AT5 (5mm), AT8 (8mm), AT10 (10mm), AT15 (15mm), AT20 (20mm)
Material: Polyurethane only (steel cord standard, Kevlar available)
Open-end: Available in all six pitches
FDA/food contact: Available in FDA-compliant polyurethane grades
Related family: T-profile (standard version, lower load capacity, different pulleys)
AT-Profile Pitch Comparison
The six AT-profile pitches cover the full range from compact precision drives to the heaviest belt-driven positioning systems. Each pitch has a dedicated page with detailed specifications, part number decoders, width guides, and FAQs.
| Profile | Pitch | Load Class | Common Widths | Typical Applications |
|---|---|---|---|---|
| AT3 | 3mm | Light to moderate | 6 to 16mm | Precision servo drives, miniature linear motion, medical instruments |
| AT5 | 5mm | Moderate to heavy | 6 to 50mm | Linear motion, European automation, packaging, printing |
| AT8 | 8mm | Heavy | 10 to 75mm | Heavy linear motion, large gantries, CNC routers |
| AT10 | 10mm | Very heavy | 16 to 100mm | Industry standard for heavy gantries, CNC, waterjet, heavy automation |
| AT15 | 15mm | Extreme | 25 to 150mm | Largest gantry systems, stone processing, bridge crane positioning |
| AT20 | 20mm | Maximum | 50 to 150mm | Absolute heaviest belt-driven positioning. Specialty pitch. |
AT10 is the most widely specified AT-profile pitch, serving as the workhorse for heavy linear motion and industrial positioning. AT5 is the most popular for precision automation and lighter linear motion. AT15 and AT20 are specialty pitches for the most extreme loads.
AT-Profile vs. T-Profile: Why the AT Upgrade?
The AT-profile was developed to overcome the load capacity limitations of the standard T-profile. By widening the tooth base and optimizing the root geometry, AT-profile belts can carry significantly more load per tooth without increasing the belt pitch or width.
| Factor | T-Profile (Standard) | AT-Profile (Modified) |
|---|---|---|
| Tooth shape | Standard trapezoidal (narrow base) | Modified trapezoidal (wider base, optimized root) |
| Load capacity | Standard | Significantly higher (same pitch and width) |
| Tooth root stress | Concentrated at corners | Distributed more evenly |
| Tooth shear resistance | Standard | Improved |
| Pulleys | T-profile pulleys | AT-profile pulleys (wider grooves) |
| Interchangeable? | NO. Different tooth geometry. Different pulleys. Do not mix T and AT. | |
| Pitches | T2.5, T5, T10 | AT3, AT5, AT8, AT10, AT15, AT20 |
| Material | Polyurethane or neoprene | Polyurethane only |
| When to choose | Replacing existing T-profile equipment | New designs needing higher load. Heavy linear motion. Upgrades. |
AT-Profile vs. HTD: Two Approaches to Higher Load
Both the AT-profile and HTD (High Torque Drive) systems were developed to exceed the load capacity of earlier trapezoidal designs, but they use fundamentally different approaches.
| Factor | AT-Profile | HTD (3M, 5M, 8M, 14M) |
|---|---|---|
| Tooth form | Modified trapezoidal (wider base, still angled sides) | Curvilinear (rounded, semi-circular) |
| Design approach | Optimized the trapezoidal form for better stress distribution | Replaced the trapezoidal form entirely with curves |
| Origin | European (evolution of T-profile) | North American/global (RMA/ISO) |
| Material | Polyurethane only (steel/Kevlar cord) | Neoprene (standard) and polyurethane |
| Open-end availability | Standard in all pitches | Available but less common |
| Linear motion standard | Yes, AT is the European linear motion standard | Less common for linear motion |
| Comparable pitches | AT5 vs 5M, AT8 vs 8M, AT10 vs T10/8M, AT15 vs 14M | 5M vs AT5, 8M vs AT8, 14M vs AT15 |
| When to choose | European equipment. Linear motion. Urethane required. | Global standard. General heavy-duty rotary drives. |
AT-Profile Part Number Format
AT-profile part numbers follow the same metric convention as T-profile: pitch length in millimeters, profile code, hyphen, width in millimeters.
| Example | Profile | Pitch Length | Width | Teeth |
|---|---|---|---|---|
| 210AT3-10 | AT3 | 210mm | 10mm | 70 |
| 500AT5-25 | AT5 | 500mm | 25mm | 100 |
| 720AT8-32 | AT8 | 720mm | 32mm | 90 |
| 1000AT10-50 | AT10 | 1000mm | 50mm | 100 |
| 1350AT15-75 | AT15 | 1350mm | 75mm | 90 |
| 2200AT20-100 | AT20 | 2200mm | 100mm | 110 |
Divide the pitch length by the pitch to calculate teeth: 1000 / 10 = 100 teeth. Some manufacturers reverse the format. Open-end AT-profile belts are designated by profile and width only (for example, AT10-50 open-end). Texas Belting can cross-reference AT-profile part numbers from any manufacturer. Call 888-203-2358 or see our Pitch Chart.
AT-Profile Materials and Construction
AT-profile belts are manufactured exclusively from polyurethane. The AT system was designed around polyurethane construction, and neoprene AT-profile belts are not produced.
Steel Cord (Standard)
Steel wire tensile cord provides near-zero elongation (0.02%) and is the standard for linear motion, precision positioning, and indexing applications. Steel cord AT-profile belts are the most commonly ordered format.
Kevlar Cord
Kevlar (aramid) cord provides superior flex life around smaller pulleys with low elongation (0.3 to 0.5%). Specified for rotary drives where belt flex fatigue is a concern. Less common than steel cord for AT-profile applications.
Open-End Roll Stock
Open-end AT-profile belts are the standard format for linear motion. Available in all six pitches, sold by the meter, and cut to any required length. Joined with mechanical connectors or heat welding. Texas Belting can supply pre-cut, pre-welded loops from open-end stock.
FDA Compliance
AT-profile belts are available in FDA-compliant polyurethane grades meeting FDA 21 CFR 177.2600 and EU 10/2011 for food contact. Commonly specified at AT5 and AT10 pitches for European food processing equipment. See Food Grade Timing Belts.
Common AT-Profile Applications
| Application | Recommended Pitch | Notes |
|---|---|---|
| Precision servo drives (compact) | AT3, AT5 | Higher load than 3M or T5 at same pitch |
| Linear motion and positioning | AT5 (light), AT10 (heavy) | Open-end steel cord standard. Near-zero stretch. |
| CNC routers and cutting tables | AT10, AT15 | Heavy gantry, long travel, precision positioning |
| Waterjet and plasma tables | AT10, AT15, AT20 | Extreme gantry weight, high acceleration |
| European industrial automation | AT5, AT8, AT10 | Standard AT-profile on European positioning systems |
| Packaging machinery | AT5, AT8 | Precise indexing at moderate to heavy loads |
| Food processing | AT5, AT10 | FDA urethane for European food equipment |
| Pick-and-place and palletizing | AT8, AT10 | Heavy carriage, fast cycles, precision placement |
| Medical and semiconductor | AT3, AT5 | Low particulate, cleanroom compatible, precision |
| Bridge cranes and heavy material handling | AT15, AT20 | Extreme-load positioning, specialty applications |
For a full comparison of AT-profile against other timing belt systems, see the Timing Belt Selection Guide and Tooth Profiles Explained.
AT-Profile Timing Belt Brands We Carry
| Brand | AT-Profile Products | Notes |
|---|---|---|
| Gates | PowerGrip AT (limited range) | Smaller AT selection. Stronger in HTD and Poly Chain. |
| Continental / ContiTech | Synchroflex AT3 through AT20 | Industry leader in AT-profile urethane. Broadest AT range. |
| Bando | Bando AT-profile | High-quality Japanese manufacturing |
| Diesel Belting | Diesel AT-profile | Cost-effective replacement option for common AT sizes |
| Megadyne | Megalinear AT3 through AT20 | Open-end specialist. Strong AT range across all pitches. |
Continental and Megadyne carry the broadest AT-profile selections. Call 888-203-2358 with your AT-profile requirements for availability and pricing.
AT-Profile Timing Belt FAQs
Need AT-Profile Timing Belts?
Tell us the pitch, part number, or application details. We stock all six AT pitches for fast shipping from Houston.
