Price range: $0.50 through $40.50
S3M Timing Belt | 3mm STD STS Belt for Servo CNC Drives
The S3M STD belt uses a 3.00 mm flat-top semi-circular tooth for lower backlash and quieter servo motion. Same pitch as HTD 3M, but different tooth geometry — not interchangeable.
Widths: 6 / 9 / 12 / 15 mm (custom on request)
Profile: STD / STS (Super Torque Drive)
Build: chloroprene rubber (CR) body· Glass fiber cord · Nylon 66 tooth facing
MOQ: 200 pcs for standard sizes, 500 pcs for custom.
Pitch length: 114–4500 mm · select size from product options ·
Made to ISO 13050 dimensional standards for global interchangeability.
[ez-toc]
S3M STD Synchronous Belt — 3.00 mm modified curvilinear tooth for precision automation, CNC feeds, robotics and medical drives. Not HTD 3M. Not interchangeable.
The S3M Synchronous Belt is the 3.00 mm pitch member of the STD / STS (Super Torque Drive) curvilinear belt family. It transmits power by tooth-and-groove meshing, so there is no slip and no speed drift — exactly what servo systems and precision feeders need.
The flat-top semi-circular tooth increases contact area at the pulley root, cuts backlash and holds repeatable positioning better than a standard HTD 3M tooth of the same pitch. The belt needs no lubrication, creates no pollution and runs quietly.
Transmission efficiency reaches 98% or more, the speed ratio extends to 1:10, and the allowed line speed reaches 45 m/s. Multi-shaft drives are supported.
Both belts have a 3.00 mm pitch. That is where the similarity ends.
| Item | STS / STD S3M | HTD 3M |
|---|---|---|
| Tooth shape | Flat-top semi-circular (modified curvilinear) | Full round arc |
| Backlash | Lower backlash — higher positioning repeatability | Slightly higher backlash than S3M |
| Noise | Quieter under servo load | Can be noisier |
| Best for | Precision automation, CNC feed, robots, medical | General high-torque industrial drives |
| Pulley | S3M / STS pulley only | HTD 3M pulley only |
| Interchangeable? | No — same pitch, different tooth geometry | |
Common widths: 6 / 9 / 12 / 15 mm. Custom widths available on request. Standard: ISO 13050 compatible (STD/STS profile). All S3M timing belts are manufactured to the STD/STS 3 mm flat-top curvilinear profile specification with a 1.14 mm tooth height and a 2.20 mm belt thickness, ensuring full dimensional interchangeability with equivalent-profile S3M (STD/STS) timing belts from other mainstream international manufacturers.

High-strength glass fiber cord. Very low elongation, stable pitch length under load.
Synthetic chloroprene rubber (CR), blended with hydrogenated nitrile and additives. Heat, cold, oil, water and chemical resistance.
Specially treated Nylon 66 elastic fabric. Low friction, high wear resistance, preserves the flat-top tooth form.
Flat-top curvilinear teeth seat firmly, keeping servo positioning repeatable.
Tooth meshing holds the speed ratio even under varying load.
Less mesh impact than HTD 3M in precision feeder and robot axes.
Line speed up to 45 m/s with stable, low-vibration running.
3 mm pitch allows small pulley diameters and space-saving layouts.
Good ozone, aging, heat and wear resistance from the chloroprene rubber (CR).
Resists oil, water, acids and alkalis in standard construction.
No lubrication, no pollution, minimal upkeep.

The STD S3M (also called STS S3M) timing belt is the 3.00 mm pitch member of the STD / STS (Super Torque Drive) curvilinear-tooth belt family. It uses a flat-top semi-circular (modified curvilinear) tooth with a 1.14 mm tooth height and a 2.20 mm belt thickness, and is engineered for precision micro drives where low backlash and accurate positioning are essential.
No. Both belts use a 3 mm pitch, but the tooth profile is different. S3M has a flat-top semi-circular (modified curvilinear) tooth, while HTD 3M has a full-round arc tooth. Pulley grooves are not the same shape, so an S3M belt will not seat correctly on an HTD 3M pulley and vice versa - the two are not interchangeable.
The designation follows pitch length - profile - belt width. So 300-S3M-09 means a 300 mm pitch line length, an STD S3M profile with a 3 mm pitch, and a 9 mm belt width. To find the number of teeth, divide the pitch length by 3: 300 / 3 = 100 teeth.
We stock 343 standard models in widths of 6 mm, 9 mm, 12 mm and 15 mm, with pitch lengths from 114 mm to 4500 mm. Non-standard widths and custom lengths can be manufactured on request.
Yes. Our S3M timing belts are manufactured to the STD/STS 3 mm flat-top profile specification with a 1.14 mm tooth height and a 2.20 mm belt thickness, and are fully dimensionally interchangeable with equivalent-profile S3M (STD/STS) timing belts from other mainstream international manufacturers.
STD S3M belts are used in precision servo drives and linear modules, CNC feed drives and tool changers, robotics joint and lightweight actuator drives, medical and laboratory equipment, office printers and plotters, ATMs, vending machines, miniature conveyors and light automation equipment.
The minimum order quantity is 100 pieces for standard models and 200 pieces for custom sizes. Stock items ship quickly, and production lead times for custom or OEM orders are confirmed when you place your order.
Need an S3M Belt?
Tell us pitch length and width. We confirm STD/STS compatibility and quote from stock lengths.
Related: S5M STD Timing Belt | 3M Timing Belt | Full Catalog
is proudly powered by WordPress