Double-Sided (DL) Timing Belts
Double-Sided (DL) Timing Belts
Double-sided timing belts are polyurethane synchronous belts with teeth molded on both sides, enabling them to drive pulleys from either face simultaneously. This is essential for serpentine drive layouts, counter-rotating shaft arrangements, and complex multi-pulley systems that require positive tooth engagement on both belt surfaces. Double-sided belts are designated "DL" (Doppelzahnriemen / double-toothed).
Texas Belting stocks double-sided belts in both T-Series (trapezoidal) and AT-Series (curvilinear) tooth profiles, including a self-tracking ATK variant and an imperial H-pitch option. Available in open-ended, welded, and truly endless configurations.
- Teeth on both sides of the belt
- Profiles: T5, T10, T20, AT5, AT10, AT20, H (12.7mm)
- Self-tracking ATK10K6 DL variant available
- Widths: 10mm to 100mm depending on profile
- Configurations: open-ended, welded, truly endless
- Both sides use same pitch (symmetrical)
- Tension members: steel cord, stainless steel, aramid
- FDA food-grade materials available
Available Double-Sided Profiles and Widths
The table below lists all available double-sided belt profiles with their widths and configurations. Both T-Series and AT-Series profiles are available, plus one imperial (H) and one self-tracking (ATK) option.
| Profile | Pitch | Available Widths (mm) | Configurations |
|---|---|---|---|
| DL-T5 | 5mm | 10, 16, 25, 32, 50 | Open-ended, welded, truly endless |
| DL-T10 | 10mm | 16, 25, 32, 50, 75, 100 | Open-ended, welded, truly endless |
| DL-T20 | 20mm | 25, 32, 50, 75, 100 | Open-ended, welded |
| DL-AT5 | 5mm | 10, 16, 25, 32, 50 | Open-ended, welded, truly endless |
| DL-AT10 | 10mm | 16, 25, 32, 50, 75, 100 | Open-ended, welded, truly endless |
| DL-AT20 | 20mm | 25, 32, 50, 75, 100 | Open-ended, welded |
| ATK10K6 DL | 10mm | Contact us | Truly endless (with K6 self-tracking) |
| H DL | 12.7mm (1/2") | Contact us | Welded, truly endless |
Serpentine Drive Design Considerations
When designing a serpentine or multi-shaft drive with double-sided belts, both the tooth side and back side engage pulleys simultaneously. Key design factors to consider:
| Factor | Recommendation |
|---|---|
| Teeth in mesh per pulley | Minimum 6 teeth in mesh on each pulley to prevent tooth jumping |
| Belt width selection | Size belt for combined load of all driven shafts, not just the heaviest single shaft |
| Tensioning | Use adjustable toothed idler pulleys on slack spans (smooth idlers cannot be used on toothed surfaces) |
| Pitch matching | Both sides use the same pitch; all pulleys in the drive must be the same pitch |
| Noise management | PAZ (polyamide) coating on both tooth surfaces significantly reduces engagement noise |
| Number of pulleys | Practical serpentine drives typically use 4 to 8 pulleys; each additional pulley adds friction losses |
Tension Member Options
Double-sided belts are available with the same tension member options as all polyurethane timing belts. For more detail on materials and their properties, see the timing belt materials guide.
| Tension Member | Material | Best For |
|---|---|---|
| Steel cord | High-carbon steel | Maximum strength, minimal elongation |
| Stainless steel | Corrosion-resistant alloy | Washdown, chemical, and outdoor environments |
| Aramid (Kevlar) | Synthetic fiber | Non-magnetic applications, lightweight drives |
Common Applications
Double-sided timing belts are specified wherever a single belt must drive multiple shafts rotating in both directions or where serpentine routing provides the most compact layout. Typical applications include multi-shaft printing press drives, packaging machinery with counter-rotating rollers, textile machinery with synchronized counter-rotating spindles, multi-axis robotic systems, paper and film processing equipment, and any serpentine drive system that would otherwise require multiple single-sided belts or gear trains.
Frequently Asked Questions
Double-sided (DL) timing belts have teeth molded on both sides of the belt, allowing them to drive pulleys on either face simultaneously. This enables serpentine drive layouts where a single belt drives multiple shafts, with some rotating clockwise and others counterclockwise. Both sides use the same pitch and tooth profile.
Double-sided belts are available in T-Series profiles (T5, T10, T20), AT-Series profiles (AT5, AT10, AT20), an imperial H pitch (12.7mm) variant, and a self-tracking ATK10K6 variant with integrated K6 V-guide. Both sides of the belt always use the same pitch and profile.
No. Both sides of a double-sided belt use the same pitch. The belt is symmetrical, with identical teeth on each face. All pulleys in the drive must be the same pitch. If your application requires different pitches on different shafts, separate single-sided belts are needed.
There is no fixed maximum, but practical serpentine drives typically use 4 to 8 pulleys. Each additional pulley adds friction losses and requires careful tensioning. The belt must have at least 6 teeth in mesh with each pulley to prevent tooth jumping under load. Contact Texas Belting at 888-203-2358 for help designing multi-pulley serpentine drives.
Double-sided drives are tensioned using adjustable toothed idler pulleys positioned on the slack span. Since both sides have teeth, smooth (toothless) idlers cannot be used in most positions because they would not clear the teeth. Spring-loaded toothed tensioners are recommended for maintaining consistent tension. For tensioning hardware, see the accessories page.
Double-sided belts may produce more engagement noise because teeth are meshing on both sides simultaneously. Adding PAZ (polyamide fabric) coating to both tooth surfaces significantly reduces noise levels and is recommended for noise-sensitive environments. PAZ coating also reduces tooth wear and improves the belt's meshing characteristics.
Yes. Double-sided belts are available in FDA 21 CFR 177.2600 compliant polyurethane with stainless steel tension members. Both tooth surfaces meet food contact requirements, making them suitable for serpentine drives in food handling and packaging lines. See the food-grade timing belts page for details.
T-Series DL belts are suitable for existing T-profile drives and general-purpose serpentine layouts. AT-Series DL belts provide up to 30% more power capacity with lower backlash and are recommended for new designs, high-load drives, and applications where precision is important. Both series are available in the same pitch range (5mm, 10mm, 20mm).
Need Double-Sided Timing Belts?
Send us your profile, width, length, and drive layout details. We will confirm availability and pricing.