8M Timing Belts: 8mm Pitch, HTD Curvilinear
8M timing belts are 8mm pitch synchronous belts with an HTD (High Torque Drive) curvilinear tooth profile. The 8M pitch is the workhorse of medium-to-heavy industrial timing belt applications, offering significantly higher torque capacity than the 5M pitch while keeping drive dimensions more compact than the 14M. It is one of the most commonly specified pitches for packaging lines, conveyors, printing equipment, and machine tool drives.
Texas Belting stocks over 1,000 8M timing belt SKUs in widths from 12mm to 85mm, with pitch lengths ranging from approximately 480mm to over 4,000mm. We carry standard neoprene 8M belts from Diesel Belting, Bando, and Continental, plus Gates 8MGT Poly Chain GT Carbon belts for high-performance and maintenance-free drives.
Quick Specs: 8M Timing Belts
Pitch: 8mm (0.315")
Tooth profile: HTD curvilinear (rounded)
Tooth height: 3.36mm
Standard widths: 12mm, 20mm, 30mm, 50mm, 85mm
Body material: Neoprene (standard), polyurethane, HNBR
Tensile cord: Fiberglass (standard), Kevlar, carbon fiber
Temperature range: -30°F to +185°F (neoprene)
Profile family: HTD (High Torque Drive)
Compatible profiles: GT2 8M, 8MGT (backward compatible on HTD pulleys)
How to Read an 8M Timing Belt Part Number
8M belt part numbers encode pitch length, pitch, and width. Here is how to decode the most common formats you will see:
| Part Number | Pitch Length | Pitch | Width | Notes |
|---|---|---|---|---|
| 800-8M-20 | 800mm | 8mm (8M) | 20mm | Standard format: Length-Pitch-Width |
| 1040-8M-30 | 1040mm | 8mm (8M) | 30mm | Common mid-range size for conveyors |
| 1040-8M-12 | 1040mm | 8mm (8M) | 12mm | Narrow belt for lighter-load drives |
| Gates 8MGT-640-36 | 640mm | 8mm (GT) | 36mm | Gates Poly Chain GT Carbon format: Pitch-GT-Length-Width |
| Gates 8MGT-800-21 | 800mm | 8mm (GT) | 21mm | Poly Chain GT Carbon, polyurethane body with carbon cord |
| D2400-8M-85 | 2400mm | 8mm (8M) | 85mm | "D" prefix indicates double-sided (teeth on both sides) |
If the part number is worn or unreadable, measure the pitch across 10 teeth with a caliper and divide by 10. A result close to 8mm confirms an 8M belt. Then measure the width and count total teeth to calculate pitch length (teeth x 8mm). See our full timing belt measurement guide for step-by-step instructions.
8M Timing Belt Widths
8M belts are available in a wider range of widths than smaller-pitch belts, reflecting the heavier loads this pitch is designed to handle. The width must match your pulleys.
| Width | Typical Use | Relative Load Capacity |
|---|---|---|
| 12mm | Light-to-medium drives, smaller equipment, space-constrained applications | Low |
| 20mm | General-purpose industrial drives, the most common 8M width | Medium |
| 30mm | Medium-heavy drives, packaging equipment, conveyors | Medium-high |
| 50mm | Heavy-duty drives, large conveyors, high-torque machine tools | High |
| 85mm | Maximum load capacity for 8M pitch, heavy industrial drives | Very high |
Gates Poly Chain GT Carbon 8M belts use different standard widths (12, 21, 36, 62mm) based on their proprietary sizing. Contact us if you need help matching a Poly Chain width to a standard 8M pulley.
8M Belt Material and Construction Options
Standard Neoprene (Most Common)
The default 8M belt construction is a neoprene body with fiberglass tensile cords and nylon tooth facing. This is the standard choice for general industrial drives operating at standard temperatures in clean, dry environments. Neoprene 8M belts provide reliable performance at a competitive price point and are available from every manufacturer we carry.
Poly Chain GT Carbon (Gates)
Gates 8MGT Poly Chain GT Carbon belts are the premium option for 8M drives. They use a polyurethane body with carbon fiber tensile cords, delivering up to three times the horsepower rating of standard neoprene 8M belts at the same pitch. Poly Chain belts resist oils, chemicals, and moisture better than neoprene, require no re-tensioning, and are lighter weight. They are the go-to choice when you need to maximize drive capacity, reduce maintenance, or extend belt life in demanding environments. Texas Belting stocks a full range of 8MGT sizes.
Polyurethane / Urethane
Polyurethane 8M belts offer superior abrasion resistance and chemical resistance over neoprene, and are FDA compliant for food-contact applications. Available with Kevlar or steel cord reinforcement. Choose urethane when your application involves food handling, chemical exposure, washdown, or FDA/USDA compliance requirements. See our Urethane Timing Belts page for more details.
Double-Sided 8M Belts
Double-sided (twin power) 8M belts have teeth on both faces, allowing the belt to drive pulleys from either side. Used in serpentine drive layouts and multi-shaft systems where the belt must engage pulleys on both its inner and outer surfaces. We stock double-sided 8M belts in multiple widths up to 85mm.
8M vs Other Timing Belt Pitches
The 8M pitch fills the gap between light-duty 5M drives and heavy-duty 14M drives. Here is how it compares to the most common neighboring pitches.
| Feature | 5M (5mm) | 8M (8mm) | 14M (14mm) |
|---|---|---|---|
| Torque capacity | Low to medium | Medium to high | High to very high |
| Speed range | Moderate to high | Moderate | Low to moderate |
| Minimum pulley size | Smaller (compact drives) | Moderate | Larger |
| Tooth height | 2.06mm | 3.36mm | 6.02mm |
| Standard widths | 9, 15, 20, 25mm | 12, 20, 30, 50, 85mm | 40, 55, 85, 115, 170mm |
| Typical applications | Packaging, CNC, automation | Conveyors, packaging lines, printing, machine tools | Heavy conveyors, mining, aggregate, large industrial |
If your current 5M drive is running at or near maximum torque capacity, stepping up to an 8M pitch (with new pulleys) provides significantly more headroom. If your 8M drive needs more capacity without changing pulleys, a Poly Chain GT Carbon 8MGT belt is the first upgrade to consider before moving to 14M. Browse all timing belt pitches and profiles.
Common 8M Timing Belt Applications
8M belts are used in medium-to-heavy industrial drives where the 5M pitch does not provide enough torque capacity but the 14M is larger than necessary. These are the most common applications our customers order 8M belts for.
| Application | Why 8M | Typical Width |
|---|---|---|
| Packaging machinery | Higher torque for heavy product handling at production speeds | 20mm, 30mm |
| Conveyor drives | Positive, no-slip drive for medium-duty conveyors under varying loads | 20mm, 30mm, 50mm |
| Printing equipment | Consistent speed and registration for larger format presses | 20mm, 30mm |
| Machine tools | Precise spindle drives and axis positioning with higher torque | 20mm, 30mm, 50mm |
| Food processing (urethane) | FDA-compliant material for heavier food conveyor and drive applications | 20mm, 30mm, 50mm |
| Textile machinery | Synchronized multi-shaft drives at medium-to-high torque | 20mm, 30mm |
| Wood and paper processing | Durable positive drive in dusty, high-load environments | 30mm, 50mm, 85mm |
| Material handling and automation | Repeatable positioning for heavier pick-and-place and transfer systems | 20mm, 30mm |
| Aggregate and mining (lighter duty) | Positive drive for screening, sorting, and feeder equipment | 50mm, 85mm |
8M Timing Belt Brands We Stock
| Brand | 8M Product Lines | Construction |
|---|---|---|
| Gates | PowerGrip HTD 8M, PowerGrip GT3 8M, Poly Chain GT Carbon 8MGT | Neoprene, polyurethane, carbon cord |
| Continental / ContiTech | Synchroforce HTD 8M | Neoprene, fiberglass cord |
| Bando | Synchro-Link HTD 8M | Neoprene, fiberglass cord |
| Diesel Belting | Standard HTD 8M, Double-Sided 8M | Neoprene, fiberglass cord |
| Megadyne | ISORAN HTD 8M | Neoprene, polyurethane |
We cross-reference 8M belt part numbers across all manufacturers. If you have a Gates 8MGT belt and need a standard neoprene equivalent (or vice versa), send us the part number and we will confirm the match and any differences in capacity or construction.
Standard 8M vs Gates 8MGT Poly Chain GT Carbon
The Gates 8MGT Poly Chain GT Carbon is the most popular upgrade from standard neoprene 8M belts. Here is how they compare.
| Feature | Standard Neoprene 8M | Gates 8MGT Poly Chain GT Carbon |
|---|---|---|
| Body material | Neoprene (polychloroprene) | Polyurethane |
| Tensile cord | Fiberglass | Carbon fiber |
| Power capacity | Standard | Up to 3x higher than standard neoprene at same pitch |
| Chemical resistance | Moderate (oils, grease) | Superior (oils, chemicals, moisture, ozone) |
| Re-tensioning | May require periodic re-tensioning | No re-tensioning needed |
| Weight | Standard | Lighter (reduced rotating mass) |
| Cost | Lower upfront | Higher upfront, lower total cost of ownership |
| Best for | Standard drives, budget replacements | High-torque drives, harsh environments, long service intervals |
Bottom line: If you are replacing a standard 8M belt and the drive is running well within its capacity, a neoprene replacement is the most cost-effective option. If you are experiencing premature belt failure, need more torque capacity, or want to reduce maintenance downtime, upgrading to Poly Chain GT Carbon on the same pulleys delivers a significant performance improvement.
8M Timing Belt FAQs
What is an 8M timing belt?
An 8M timing belt is a synchronous (toothed) power transmission belt with an 8mm pitch, meaning the distance between adjacent tooth centers is 8mm. It uses an HTD (High Torque Drive) curvilinear tooth profile. The 8M pitch is designed for medium-to-heavy industrial drives including conveyors, packaging equipment, printing presses, and machine tools.
What does 8M mean on a timing belt?
The "8M" designation means 8mm pitch with a metric HTD tooth profile. In a standard part number like 800-8M-20, the first number (800) is the pitch length in millimeters, "8M" is the pitch, and the last number (20) is the belt width in millimeters.
What widths do 8M timing belts come in?
Standard neoprene 8M belt widths are 12mm, 20mm, 30mm, 50mm, and 85mm. The 20mm width is the most common for general-purpose applications. Gates Poly Chain GT Carbon 8MGT belts use different standard widths: 12mm, 21mm, 36mm, and 62mm. Wider belts carry more torque.
Can I replace a standard 8M belt with a Poly Chain GT Carbon belt?
Yes, in most cases. Gates 8MGT Poly Chain GT Carbon belts are compatible with standard HTD 8M pulleys. The upgrade provides significantly higher power capacity, better chemical resistance, and no re-tensioning. Note that Poly Chain belts use different standard widths than neoprene 8M belts, so check that the Poly Chain width matches or is compatible with your pulley. Contact us and we will confirm compatibility for your specific setup.
What is the difference between 8M and 8MGT?
8M refers to the standard HTD 8mm pitch timing belt, typically neoprene with fiberglass cord. 8MGT is the Gates designation for their Poly Chain GT Carbon belt in 8mm pitch, which uses a polyurethane body with carbon fiber tensile cord. The 8MGT delivers much higher power ratings than standard 8M belts. Both use the same 8mm pitch and are compatible with HTD 8M pulleys.
Are double-sided 8M timing belts available?
Yes. Double-sided (twin power) 8M belts have teeth on both faces and are used in serpentine drive layouts where the belt must engage pulleys on both its inner and outer surfaces. We stock double-sided 8M belts in widths up to 85mm. Part numbers with a "D" prefix (e.g., D2400-8M-85) indicate double-sided construction.
How many 8M timing belts does Texas Belting stock?
We stock over 1,000 8M timing belt SKUs across multiple widths, lengths, brands, and constructions at our Houston warehouse. Standard neoprene 8M belts in 20mm and 30mm widths are almost always in stock for same-day shipping. Poly Chain GT Carbon 8MGT belts are also stocked in popular sizes. Less common lengths or widths typically ship within 3 to 5 business days.
How do I measure an 8M timing belt for replacement?
Measure the pitch by spanning 10 teeth with a caliper or ruler and dividing by 10. A result close to 8mm confirms an 8M belt. Make sure the teeth are rounded (curvilinear), not straight-sided (which would indicate an H trapezoidal belt at a different pitch). Measure width straight across the belt. For pitch length, count total teeth and multiply by 8mm, or check the first number in the part number. See our complete timing belt measurement guide.
8M Drive Components
Every 8M belt needs a matched 8M sprocket. The sprocket tooth profile must match the belt profile exactly. Browse our HTD drive components, or see our Sprocket Selection Guide for help choosing the right one.
Profile warning for 8M sprockets: HTD 8M, GT3 8M, and Poly Chain 8M sprockets all share 8mm pitch but use different tooth groove geometries. For general industrial drives, standard HTD 8M sprockets work with all three belt types. For precision or servo applications, match the sprocket to the specific belt profile (HTD, GT3, or Poly Chain) for optimal performance. Contact us if you are unsure which sprocket matches your belt.
Related Pages
← All Timing Belts • HTD Timing Belts • 5M Timing Belts • 14M Timing Belts • 3M Timing Belts • GT Timing Belts • H Timing Belts • Gates Timing Belts • Poly Chain GT Carbon • Tooth Profiles Explained • Timing Belt Selection Guide • Pitch Chart • How to Measure • Troubleshooting Guide • Urethane Timing Belts • Food Grade Timing Belts • Pulleys, Sheaves & Sprockets
