* { box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, ‘Segoe UI’, Roboto, Arial, sans-serif; color: #1f2937; line-height: 1.75; margin: 0; padding: 0; background: #fff; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 20px; }

.hero { background: linear-gradient(135deg, #042f2e 0%, #065f46 55%, #10b981 100%); color: #fff; border-radius: 0 0 32px 32px; padding: 48px 0 40px; margin-bottom: 32px; }
.hero-inner { display: flex; gap: 40px; align-items: center; flex-wrap: wrap; }
.hero-text { flex: 1 1 420px; }
.hero-text h1 { font-size: 29px; line-height: 1.25; margin: 0 0 12px; font-weight: 800; }
.hero-text h1 span { color: #6ee7b7; }
.hero-text .sub { font-size: 16px; opacity: .92; margin-bottom: 18px; }
.hero-img { flex: 1 1 320px; }
.hero-img img { width: 100%; height: auto; border-radius: 16px; box-shadow: 0 20px 40px rgba(0,0,0,.3); display: block; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 20px; }
.hero-tags span { background: rgba(255,255,255,.14); border: 1px solid rgba(255,255,255,.25); padding: 5px 14px; border-radius: 999px; font-size: 13px; font-weight: 600; }
.quote-card { background: #f59e0b; color: #111827; padding: 16px 20px; border-radius: 14px; font-weight: 700; text-align: center; margin-top: 22px; }

.sec { margin: 56px 0 0; }
.sec-title { display: flex; align-items: center; gap: 12px; margin-bottom: 24px; }
.sec-title .bar { width: 6px; height: 32px; background: #10b981; border-radius: 3px; }
.sec-title h2 { font-size: 24px; margin: 0; color: #0f172a; }

.spec-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px,1fr)); gap: 14px; }
.spec-card { background: #ecfdf5; border: 1px solid #a7f3d0; border-radius: 14px; padding: 18px; }
.spec-card .lbl { font-size: 12px; text-transform: uppercase; letter-spacing: .06em; color: #047857; font-weight: 700; }
.spec-card .val { font-size: 22px; font-weight: 800; color: #0f172a; margin-top: 6px; }
.spec-card .val small { font-size: 13px; font-weight: 600; color: #64748b; }

.layer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px,1fr)); gap: 18px; }
.layer-card { border-radius: 16px; padding: 24px; color: #fff; }
.layer-card.l1 { background: linear-gradient(135deg,#047857,#10b981); }
.layer-card.l2 { background: linear-gradient(135deg,#064e3b,#065f46); }
.layer-card.l3 { background: linear-gradient(135deg,#334155,#475569); }
.layer-card .num { font-size: 13px; font-weight: 700; opacity: .85; }
.layer-card h3 { margin: 8px 0; font-size: 18px; }
.layer-card p { font-size: 14px; margin: 0; opacity: .92; }

.adv-list { counter-reset: adv; display: flex; flex-direction: column; gap: 12px; }
.adv-item { display: flex; gap: 16px; align-items: flex-start; background: #fff; border: 1px solid #a7f3d0; border-radius: 12px; padding: 16px 20px; counter-increment: adv; }
.adv-item::before { content: counter(adv); flex: 0 0 36px; height: 36px; background: #10b981; color: #fff; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: 800; }
.adv-item h4 { margin: 0 0 4px; font-size: 16px; color: #0f172a; }
.adv-item p { margin: 0; font-size: 14px; color: #475569; }

.note-box { background: #f0fdfa; border-left: 4px solid #10b981; border-radius: 10px; padding: 18px 20px; margin-top: 18px; }
.note-box h4 { margin: 0 0 8px; color: #065f46; font-size: 16px; }
.note-box p { margin: 0; font-size: 14px; color: #334155; }

table { width: 100%; border-collapse: collapse; margin: 20px 0; display: block; overflow-x: auto; white-space: nowrap; border-radius: 12px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,.06); }
th, td { border: 1px solid #a7f3d0; padding: 12px 14px; text-align: left; font-size: 14px; }
thead th { background: #064e3b; color: #fff; }
tbody tr:nth-child(even) { background: #ecfdf5; }

.cta { background: linear-gradient(135deg,#d1fae5,#a7f3d0); border-radius: 20px; padding: 32px; text-align: center; margin: 48px 0; }
.cta h3 { margin: 0 0 12px; font-size: 22px; color: #065f46; }
.cta a { display: inline-block; background: #059669; color: #fff; padding: 12px 28px; border-radius: 999px; text-decoration: none; font-weight: 700; margin: 4px; }

.seo-foot { margin-top: 40px; padding: 20px; background: #ecfdf5; border-left: 4px solid #10b981; font-size: 13px; color: #64748b; }
.seo-foot a { color: #047857; }

@media (max-width:640px){ .hero{padding:32px 0 28px;border-radius:0 0 20px 20px;} .hero-text h1{font-size:23px;} .sec-title h2{font-size:20px;} .spec-card .val{font-size:19px;} }

S3M STD Belt 114-4500mm, 3mm 6/9/12/15mm CR, ISO 13050 Office & Home Timing Belt Supplier

S3M STD Synchronous Belt — 3.00 mm modified curvilinear tooth for precision automation, CNC feeds, robotics and medical drives. Not HTD 3M. Not interchangeable.

Overview

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.

STD S3M vs HTD 3M — Read This First

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

Download S3M STD Belt Complete Size Chart & Dimensional PDF

Technical Specifications

Tooth Pitch

3.00 mm

Tooth Height

1.14 mm

Belt Thickness

2.20 mm

Max Line Speed

45 m/s

Efficiency

98% +

Speed Ratio

Up to 1:10

Temperature

-30~+90 °C

Pitch Length

114–4500 mm

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.

S3M STD belt tooth profile and dimension chart showing a 3 mm pitch, 1.14 mm tooth height and 2.20 mm belt thickness

Materials & Construction

LAYER 01 Tensile MemberHigh-strength glass fiber cord. Very low elongation, stable pitch length under load.
LAYER 02 Body CompoundSynthetic chloroprene rubber (CR), blended with hydrogenated nitrile and additives. Heat, cold, oil, water and chemical resistance.
LAYER 03 Tooth FacingSpecially treated Nylon 66 elastic fabric. Low friction, high wear resistance, preserves the flat-top tooth form.

Why Engineers Specify S3M

Lower Backlash

Flat-top curvilinear teeth seat firmly, keeping servo positioning repeatable.

No Slip, Constant Ratio

Tooth meshing holds the speed ratio even under varying load.

Quiet Under Load

Less mesh impact than HTD 3M in precision feeder and robot axes.

High-Speed Capable

Line speed up to 45 m/s with stable, low-vibration running.

Compact Drives

3 mm pitch allows small pulley diameters and space-saving layouts.

Long Service Life

Good ozone, aging, heat and wear resistance from the chloroprene rubber (CR).

Chemical Resistance

Resists oil, water, acids and alkalis in standard construction.

Maintenance-Free

No lubrication, no pollution, minimal upkeep.

Where S3M Belts Are Used

Precision automation: servo axes, linear modules, pick-and-place heads.
CNC machinery: feed drives, tool changers, measuring carriages.
Robotics: joint drives, lightweight actuator belts.
Medical & lab equipment: scanners, pumps, diagnostic stages.
Office & instrument: printers, plotters, miniature conveyors.
Replacement on STD/STS installs: direct swap on existing S3M pulley systems.

Installation & Care

Inspect on receipt: clean surface, belt not twisted, teeth full and well formed.
Never bend or crimp — this damages the glass fiber cord.
Avoid scratches and chemicals; keep away from strong oxidising acids; limit long oil/water contact.
Release tension before removal. Never pry the belt off under load with improvised tools.
Confirm pulley profile: S3M belt goes on S3M pulley only.
Tension just enough to prevent tooth jump at maximum load.
Keep the drive clean; replace at first sign of tooth wear or cracking.

Frequently Asked Questions

What is an STD S3M timing belt?

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.

Is S3M the same as HTD 3M?

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.

How do I read an S3M model number such as 300-S3M-09?

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.

What widths and lengths are available?

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.

Are S3M timing belts interchangeable with belts from other manufacturers?

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.

What applications are S3M timing belts used for?

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.

What is the minimum order quantity and lead time?

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.

Request a Quote

Related: S5M STD Timing Belt | 3M Timing Belt | Full Catalog

Belt for Servo CNC Drives

S3M STD Belt 114-4500mm, 3mm 6-15mm CR, ISO 13050 Timing Belt