AT8 Timing Belts (8mm Modified Metric Trapezoidal)
AT8 timing belts are modified metric trapezoidal belts with an 8mm pitch, designed for heavy-duty linear motion, large gantry systems, and high-load European automation equipment. AT8 sits in the middle of the AT-profile family between AT5 (5mm) and AT10 (10mm), providing a strong balance of load capacity and compact drive size for applications that exceed AT5 limits but do not yet require the larger AT10 profile.
AT8 timing belts are manufactured from polyurethane with steel wire or Kevlar tensile cords. The AT-profile's wider tooth base and optimized root geometry deliver higher load capacity and improved tooth engagement compared to standard T-profile belts at similar pitch sizes. AT8 belts are available in both closed-loop and open-end (continuous roll) form. Texas Belting stocks AT8 timing belts for same-day shipping from Houston.
Pitch: 8mm (0.315")
Tooth profile: Modified trapezoidal (AT, wider tooth base)
Profile family: AT-Profile (AT3, AT5, AT8, AT10, AT15, AT20)
Standard widths: 10, 16, 25, 32, 50, 75mm
Primary material: Polyurethane with steel cord (standard); Kevlar cord available
Temperature range: -22°F to +176°F (-30°C to +80°C) standard
Formats: Closed-loop (welded endless) and open-end (continuous roll)
AT8 vs. 8M HTD: Different Profiles at Similar Pitch
AT8 (8mm modified trapezoidal) and 8M HTD (8mm curvilinear) share the same 8mm pitch but use completely different tooth geometries and require different pulleys. They are not interchangeable.
| Factor | AT8 (Modified Trapezoidal) | 8M HTD (Curvilinear) |
|---|---|---|
| Pitch | 8mm | 8mm |
| Tooth shape | Modified trapezoidal (wider base, angled sides) | Curvilinear (rounded, semi-circular) |
| Load capacity | Very high (optimized AT tooth root) | High (curvilinear stress distribution) |
| Pulleys | AT8 pulleys only | 8M HTD pulleys only |
| Interchangeable? | NO. Different tooth shape. Different pulleys. Will not mesh correctly. | |
| Primary material | Polyurethane (steel/Kevlar cord) | Neoprene (standard); urethane available |
| Open-end available | Yes (standard format) | Less common in open-end |
| Origin | European AT standard | North American/global HTD standard |
| Common on | European automation, heavy linear motion gantries | General global industrial heavy-duty drives |
AT8 Part Number Decoder
Standard Format: [Pitch Length]AT8-[Width]
| Part Number | Pitch Length | Width | Teeth | Construction |
|---|---|---|---|---|
| 320AT8-16 | 320mm | 16mm | 40 | Urethane, steel cord |
| 480AT8-25 | 480mm | 25mm | 60 | Urethane, steel cord |
| 720AT8-32 | 720mm | 32mm | 90 | Urethane, steel cord |
| 1120AT8-50 | 1120mm | 50mm | 140 | Urethane, steel cord |
| AT8-32 (open-end) | Per cut length | 32mm | Per length | Urethane, steel cord |
How to calculate teeth: Divide pitch length by 8. Example: 720 / 8 = 90 teeth. Open-end AT8 belts are sold by the meter and cut to any required length. Some manufacturers reverse the format (for example, 32AT8-720). Texas Belting can cross-reference AT8 part numbers from any manufacturer. Call 888-203-2358 or send us your part number.
AT8 Width Guide
| Width (mm) | Width (Inches approx.) | Typical Applications |
|---|---|---|
| 10mm | 0.39" | Light AT8 drives, uncommon. Consider AT5 for lighter loads. |
| 16mm | 0.63" | Light to moderate linear motion, small European automation |
| 25mm | 0.98" | Most common AT8 width. General linear motion and automation. |
| 32mm | 1.26" | Medium-heavy gantry systems, larger conveyors |
| 50mm | 1.97" | Heavy-duty gantry, CNC routers, waterjet tables |
| 75mm | 2.95" | Maximum standard AT8 width, heaviest AT8 loads. Consider AT10 if more capacity needed. |
Open-end urethane AT8 belts can be cut to custom widths from wider stock rolls. Contact Texas Belting for non-standard width availability.
AT8 vs. Other Heavy-Duty Timing Belt Pitches
| Profile | Pitch | Tooth Form | Load Capacity | Best For |
|---|---|---|---|---|
| AT5 | 5mm | Modified trapezoidal (AT) | Moderate to heavy | Lighter AT-family applications, precision linear motion |
| AT8 | 8mm | Modified trapezoidal (AT) | Heavy | Heavy linear motion, large gantries, European heavy automation |
| AT10 | 10mm | Modified trapezoidal (AT) | Very heavy | Heaviest AT-family applications, largest gantry systems |
| 8M (HTD) | 8mm | Curvilinear (HTD) | Heavy | General global heavy-duty drives (same pitch, different profile) |
| T10 | 10mm | Standard trapezoidal | Heavy | Standard European heavy drives (lower load than AT10 at same pitch) |
| 14M (HTD) | 14mm | Curvilinear (HTD) | Very heavy | Highest HTD load capacity, high-horsepower drives |
AT8 fills the gap between AT5 and AT10 in the AT-profile family. It competes directly with 8M HTD at the same 8mm pitch but uses a different tooth form. For existing AT8 equipment, always match the AT8 profile exactly. For new designs, evaluate both AT8 and 8M based on the pulley system, load requirements, and whether the equipment follows European (AT) or global (HTD) standards. See the Tooth Profiles Explained guide for full comparisons.
AT8 for Linear Motion
AT8 is a popular choice for medium to heavy linear motion gantry systems where AT5 has reached its load limits. The 8mm pitch provides deeper tooth engagement and greater shear strength while keeping the drive more compact than AT10.
- Open-end urethane AT8 with steel cord is the standard for heavy linear motion. Cut to any length. Joined with mechanical connectors or welded splices.
- 25mm and 32mm widths handle the majority of AT8 linear motion applications. Step up to 50mm or 75mm for the heaviest carriages.
- Steel cord provides 0.02% elongation under load, maintaining precise carriage positioning over long travel distances.
- AT8 bridges the gap between AT5 and AT10, making it ideal when AT5 at maximum width is insufficient but AT10 pulleys would be oversized for the available space.
For more detail on urethane belt materials and cord options for linear motion, see Urethane Timing Belts and Timing Belts for Linear Motion.
AT8 Timing Belt Materials
| Property | Steel Cord (Standard) | Kevlar Cord |
|---|---|---|
| Elongation | 0.02% (near-zero) | 0.3 to 0.5% |
| Best for | Linear motion, indexing, precision positioning | Rotary drives with small pulleys, high flex life |
| Minimum pulley size | Larger (steel is stiffer) | Smaller (Kevlar flexes tighter) |
| Chemical resistance | Excellent (urethane body) | Excellent (urethane body) |
| FDA available | Yes | Yes |
| Open-end available | Yes (standard) | Yes (less common) |
AT8 belts are manufactured exclusively from polyurethane. Neoprene AT8 belts are not produced. For food-contact applications, AT8 belts are available in FDA-compliant polyurethane grades. See Food Grade Timing Belts for more details.
Common AT8 Timing Belt Applications
| Application | Why AT8 | Typical Width |
|---|---|---|
| Heavy linear motion gantry | Open-end steel cord for heavy carriage positioning. Steps up from AT5. | 25 to 50mm |
| CNC routers (medium to large) | Heavy gantry travel with precise axis positioning | 25 to 50mm |
| European industrial automation | Standard AT-profile on European-designed heavy positioning systems | 16 to 32mm |
| Packaging machinery (heavy duty) | High-load indexing on large European packaging lines | 16 to 32mm |
| Pick-and-place and palletizing | Heavy-duty positioning with high acceleration and load | 25 to 50mm |
| Material handling conveyors | Open-end for custom conveyor lengths. Chemical resistant urethane. | 25 to 50mm |
| Food processing | FDA-compliant urethane for heavy food conveyor drives | 25 to 50mm |
| Waterjet and plasma tables | Heavy gantry, long travel, high acceleration requirements | 32 to 75mm |
For lighter loads, step down to AT5 (5mm). For heavier loads, step up to AT10 (10mm). See the Timing Belt Selection Guide for help choosing the right profile and pitch.
AT8 Timing Belt Brands We Carry
| Brand | AT8 Product Lines | Notes |
|---|---|---|
| Gates | PowerGrip AT8 | Limited AT range. Stronger in HTD and Poly Chain. |
| Continental / ContiTech | Synchroflex AT8 | Industry leader in AT-profile urethane belts |
| Bando | Bando AT8 | High-quality Japanese manufacturing |
| Diesel Belting | Diesel AT8 | Cost-effective replacement option |
| Megadyne | Megalinear AT8 | Open-end and closed-loop urethane. Strong AT-profile range. |
Not sure which brand to specify? Request a quote or call 888-203-2358.
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