STD Series Polyurethane Timing Belts
STD Series Polyurethane Timing Belts
STD (Super Torque Drive) polyurethane timing belts use a modified curvilinear tooth profile designated S5M and S8M. The STD profile is distinct from both HTD and AT tooth geometries and is most commonly found in equipment manufactured by Japanese and Asian OEMs, including CNC machines, industrial robots, and precision automation equipment. Polyurethane STD belts serve as direct replacements for rubber STD belts on existing S-series pulleys, delivering significantly extended service life.
Texas Belting stocks S5M and S8M polyurethane timing belts in open-ended, welded, and truly endless configurations. All belts feature steel cord or aramid tension members. Optional backings, tooth coatings, and machined modifications are available.
- Pitches: S5M (5mm), S8M (8mm)
- Tooth profile: modified curvilinear (STD/Super Torque)
- Common in Japanese and Asian OEM equipment
- Not interchangeable with HTD or AT pulleys
- S5M widths: 10, 15, 20, 25mm
- S8M widths: 20, 30, 40, 50mm
- Configurations: open-ended, welded, truly endless
- FDA food-grade materials available
STD Profile Availability and Widths
| Profile | Pitch | Available Widths (mm) | Open-Ended | Welded | Truly Endless |
|---|---|---|---|---|---|
| S5M | 5mm | 10, 15, 20, 25 | Yes | Yes | Yes |
| S8M | 8mm | 20, 30, 40, 50 | Yes | Yes | Yes |
STD Technical Specifications
For complete engineering data including tensile strength and allowable tooth loads, see the timing belt specifications reference.
| Profile | Pitch (mm) | Belt Height (mm) | Tooth Height (mm) | Min. Pulley Teeth |
|---|---|---|---|---|
| S5M | 5.0 | 3.6 | 2.1 | 14 |
| S8M | 8.0 | 5.6 | 3.4 | 22 |
STD vs. HTD vs. AT-Series Comparison
STD, HTD, and AT-Series belts all use curvilinear tooth profiles at similar pitches, but each has a distinct tooth geometry and requires its own matching pulleys. They are not interchangeable.
| Feature | STD (S5M / S8M) | HTD (5M / 8M) | AT-Series (AT5 / AT10) |
|---|---|---|---|
| Tooth profile | Modified curvilinear | Standard curvilinear | Advanced curvilinear |
| Power capacity | High | Moderate | Highest |
| Backlash | Low | Moderate | Lowest |
| Pulley compatibility | S-series pulleys only | HTD pulleys only | AT-series pulleys only |
| Primary market | Japanese / Asian OEM equipment | General industrial worldwide | European / global precision |
| Best for | Replacement on existing S-series drives | Replacement on existing HTD drives | New designs and performance upgrades |
When to Choose STD Belts
STD belts are most commonly specified as replacements for existing S5M and S8M installations, particularly in equipment from manufacturers such as Fanuc, Mitsubishi, Yaskawa, Okuma, and other Japanese and Asian machine builders. If you are designing a new drive system, AT-Series belts generally offer superior performance. For existing STD installations, polyurethane STD belts provide a significant upgrade in wear life and precision over rubber versions without requiring new pulleys.
Tension Member and Material Options
For more detail on materials and their properties, see the timing belt materials guide.
| Option | Description |
|---|---|
| Steel cord | Standard reinforcement, highest tensile strength, minimal elongation |
| Stainless steel cord | Corrosion resistant for washdown and chemical environments |
| Aramid (Kevlar) cord | Non-magnetic, lightweight for electronic and cleanroom applications |
| FDA-compliant materials | Food-contact compliant polyurethane available for both S5M and S8M |
Frequently Asked Questions
STD belts use a modified curvilinear tooth profile designated S5M (5mm pitch) and S8M (8mm pitch). The tooth geometry falls between HTD and AT-Series in terms of power capacity. STD is most commonly found in Japanese and Asian OEM equipment including CNC machines, industrial robots, and precision automation systems.
No. S5M and S8M belts require their own S-series pulleys. Although the pitch values (5mm, 8mm) match HTD and AT options, the tooth profiles are different and the belts will not engage correctly on HTD or AT pulleys. Always verify your pulley profile before ordering. If uncertain, send a belt sample to Texas Belting or call 888-203-2358 for identification assistance.
STD belts are most commonly found in equipment manufactured by Japanese and Asian OEMs, including Fanuc, Mitsubishi, Yaskawa, Okuma, and similar machine builders. They are specified in CNC machines, industrial robots, semiconductor handling equipment, and precision automation systems where the original design calls for S5M or S8M belts.
All three have a 5mm pitch, so pitch measurement alone will not distinguish them. Examine the tooth shape: S5M, 5M HTD, and AT5 each have a slightly different curvature. The belt markings or part number usually indicate the profile type. If the belt is from Japanese OEM equipment, it is most likely S5M. If uncertain, send a sample to Texas Belting for identification. We can confirm the profile and provide the correct polyurethane replacement.
Standard S5M and S8M sizes in common widths are typically available from stock or within 1 to 2 weeks. Custom widths, special materials, or truly endless configurations may require 3 to 4 weeks. Contact Texas Belting at 888-203-2358 for current availability on your specific size.
AT-Series belts offer higher power capacity and lower backlash than STD, but switching from STD to AT requires replacing all pulleys since the profiles are not interchangeable. If your equipment uses S-series pulleys and you want improved belt life without changing pulleys, polyurethane STD belts are the correct upgrade. If you are rebuilding the drive or designing new equipment, AT-Series is recommended.
Yes. S5M and S8M belts support the full range of polyurethane timing belt options including PAZ and PAR coatings, rubber and fabric backings, drilled holes, machined slots, welded profiles, and V-guides. All standard materials including FDA-grade compounds are available.
Yes. Both S5M and S8M belts are available in truly endless (molded continuous loop, no splice joint), open-ended (cut to any length), and welded endless (custom loop length) configurations. Truly endless provides the smoothest operation and longest service life for rotary drives.
Need STD (S5M / S8M) Timing Belts?
Send us your pitch, width, length, and tooth count. We will confirm the correct profile and provide a quote.