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S8M Timing Belt 280-6640mm, 8mm 15/20/25/30/50/85mm CR, ISO 13050 Supplier

Overview

The S8M timing belt is a metric-pitch member of the STD (Super Torque Drive) family, with an 8.00 mm tooth pitch. STD uses a modified curvilinear profile with a flat tooth top and deep root radii. It shares the 8 mm pitch of HTD 8M but not the tooth geometry, so the two are not interchangeable. Power is transmitted by the meshing of belt teeth with pulley grooves rather than by friction, so the drive holds its speed ratio with no slip, even under changing loads. S8M shares the 8 mm pitch of HTD 8M but uses a different tooth geometry, so the two belts and their pulleys are not interchangeable.

The modified tooth shape spreads the load across a wider flank area and relieves stress at the tooth root, which is where trapezoidal-profile belts of the same pitch fail first. S8M timing belt therefore carries more torque, runs quieter and lasts longer. It also resists ratcheting better than HTD 8M under shock loads and frequent reversals, which is why it is a common choice for servo-driven automation, machine tools and precision positioning.

S8M timing belts require no lubrication, produce no pollution and run with low noise. Transmission efficiency reaches 98% or more, the speed ratio extends to 1:10, and the allowed line speed reaches 35 m/s. Multi-shaft drives are fully supported.

Technical Specifications

Tooth Pitch

8.00 mm

Tooth Height

3.05 mm

Belt Thickness

5.30 mm

Max Line Speed

35 m/s

Transmission Efficiency

98% +

Speed Ratio

Up to 1:10

Operating Temperature

-30~+90 °C

Pitch Length Range

280–6640 mm

MOQ: 100 pcs, Common widths: 15 / 20 / 25 / 30 / 50 / 85 mm, custom widths available on request.

Download S8M Timing Belt Complete Size Chart & Dimensional PDF

All S8M timing belts are manufactured in accordance with the ISO 13050 metric curvilinear profile standard for the STD/STS tooth system, ensuring full dimensional interchangeability with equivalent-profile S8M timing belts from other mainstream international manufacturers.

Materials & Construction

Every S8M timing belt is built with a three-layer composite structure using premium, industry-grade materials for stable dimensions and a long service life.

LAYER 01 Tensile Member (Core)High-strength glass fiber cord carries the full tensile load with very low elongation, keeping pitch length stable under load.
LAYER 02 Body CompoundSynthetic chloroprene rubber (CR), blended with multiple additives for heat, cold, oil, water and chemical resistance.
LAYER 03 Tooth FacingSpecially treated Nylon 66 high-elastic fabric protects the tooth surface from wear, lowers friction and preserves tooth form.

Key Advantages

Zero Backlash, Exact Ratios

Positive tooth engagement eliminates slip entirely, so the speed ratio stays constant under changing loads.

Up to 98% Efficiency

More efficient than friction belts, with no energy lost to slip or creep.

High-Speed Capable

Line speeds up to 35 m/s with smooth, quiet running even at high RPM.

Maintenance-Free

No lubrication needed, no pollution, low noise and minimal upkeep.

Strong Dynamic Flex

Excellent flex-fatigue resistance and strong crack-propagation resistance under continuous cycling.

Built to Last

Outstanding ozone resistance, plus heat, aging and wear resistance for extended service life.

Broad Chemical Resistance

chloroprene rubber (CR) resists oil, water, acids and alkalis in standard construction.

Wide Operating Range

Operates from -30 to +90 °C without compromising performance.

Four Steps to the Right Belt

STEP 01 Confirm the Pitch

S8M timing belt uses an 8.00 mm pitch. Verify against your existing pulley tooth spacing.

STEP 02 Measure Pitch Length

Measure the centre distance or existing belt, then pick the matching S8M timing belt length from the selector above.

STEP 03 Pick the Width

Choose from 15/20/25/30/50 /85 mm, or ask us for a custom width.

STEP 04 Send Us the Details

Tell us the model, quantity and application — we will confirm availability and pricing.

STD S8M timing belt tooth profile and dimension chart showing 8 mm pitch, 3.05 mm tooth height and 5.30 mm thickness

Tooth Profile Comparison

Profile	Pitch	Tooth Shape	Best Suited For
S8M	8.00 mm	Modified Curvilinear (STD/STS)	High-speed metric precision drives, medium-heavy loads
S5M	5.00 mm	Modified Curvilinear (STD/STS)	Compact, lighter-duty metric drives
S14M	14.00 mm	Modified Curvilinear (STD/STS)	Heavy-duty, large pulley diameters
RPP8	8.00 mm	Parabolic	Alternative profile, similar pitch class
L (inch)	9.525 mm	Trapezoidal	Legacy inch-pitch replacement drives
H (inch)	12.700 mm	Trapezoidal	Heavy-duty inch-pitch drives

Applications

STD/STS S8M timing belts are widely used wherever reliable timing and compact power transmission matter:

Industrial machinery: CNC equipment, automated production lines, conveyors, packaging machinery, textile machinery.
Office & consumer equipment: Printers, copiers, paper feed mechanisms, small appliances.
Precision drives: Robotics, medical equipment, measuring instruments, high-speed positioning systems.
Replacement drives: Direct swap on existing S8M pulley installations, restoring the original speed ratio without changing the pulleys.

Installation & Care

Inspect on receipt: surface clean and tidy, belt not twisted, teeth full and well-formed.
Never bend or crimp: bending damages the glass fiber tensile member and reduces belt strength.
Avoid scratches and chemicals: do not scratch the belt; avoid chemicals, especially strong oxidising acids; minimise prolonged oil and water exposure.
Reduce tension before removal: always release tension first. Never use unauthorised tools to pry the belt off under high tension.
Check pulley alignment: pulleys must be parallel and coplanar.
Tension correctly: just enough to prevent tooth jumping under maximum load. Over-tensioning shortens bearing life.
Keep the drive clean: remove oil, dust and debris. Replace at the first sign of tooth wear or cracking.

Frequently Asked Questions

What is an S8M timing belt?

The S8M synchronous belt is a metric-pitch member of the STD/STS (Super Torque Drive) family. It uses an 8.00 mm tooth pitch, a 3.05 mm tooth height and a 5.30 mm belt thickness, and its modified curvilinear profile with a flat tooth top and deep root radii is engineered for high-speed precision drives with medium-to-heavy loads.

What is the difference between S8M and HTD 8M?

Both use an 8 mm pitch, but they are different profiles. S8M uses the STD/STS modified curvilinear tooth with a 3.05 mm tooth height, while HTD 8M uses the HTD curvilinear tooth with a 3.38 mm tooth height. Their tooth geometry and pulleys differ, so an S8M belt and an HTD 8M belt are not interchangeable.

What is the difference between S8M, S5M and S14M?

All three belong to the STD/STS modified curvilinear family and share the same tooth shape, but their pitches differ: S5M is 5 mm, S8M is 8 mm and S14M is 14 mm. Larger pitch means higher torque capacity, so S5M suits compact light drives, S8M medium-to-heavy high-speed drives, and S14M heavy-duty low-speed drives.

How do I read an S8M belt model number such as 1000-S8M-30?

The designation is pitch length – profile – width. So 1000-S8M-30 means a 1000 mm pitch line length, an S8M 8 mm modified curvilinear profile, and a 30 mm belt width. To find the number of teeth, divide the pitch length by the pitch: 1000 / 8 = 125 teeth.

What widths and lengths are available?

We stock 260 standard S8M models in widths of 15, 20, 25, 30, 50 and 85 mm, with pitch lengths from 280 mm to 6640 mm. Custom widths and non-standard lengths can be manufactured on request.

What materials and construction do S8M belts use?

Every S8M belt uses a three-layer composite construction: a high-strength glass fiber tensile cord, a chloroprene rubber (CR) body, and a nylon 66 tooth facing for wear protection and low friction. High-temperature or oil-resistant HNBR compounds are available on request.

What applications are S8M timing belts used for?

S8M belts are used for high-speed precision drives such as CNC equipment, automated production lines, conveyors, packaging and textile machinery, printers, copiers and paper feed mechanisms, robotics, medical equipment, measuring instruments, and direct replacement on existing S8M pulley installations.

Are S8M timing belts interchangeable with belts from other manufacturers?

Yes. Our S8M timing belts are manufactured to the ISO 13050 metric curvilinear profile standard for the STD/STS tooth system and are fully dimensionally interchangeable with equivalent-profile S8M timing belts from other mainstream international manufacturers, so they work as a direct replacement on standard S8M pulleys.

Need the Right S8M timing belt for Your Drive?

All standard S8M timing belt lengths and widths are available. Tell us your pitch length and width — we will confirm the model and quote within one working day.

Request a Quote

Related Products:S5M Timing Belt | 8M Synchronous Belt | Full Catalog

S8M synchronous belt

S8M Timing Belt 280-6640mm, 8mm Pitch, 15-85mm CR, ISO 13050