Many folks in 3D printing have been confused by various belt profiles. 2GT and GT2 are often used interchangeably. Here at Filastruder we offer Genuine Gates 2GT belts and pulleys, as 2GT is most common in 3D printing. We talked to an engineer at Gates Corporation with over 3 decades of experience to seek out the truth about 2GT/GT2/GT3 belts and pulleys. Let's dive in:
Glossary/Terminology:
Pitch: Distance between teeth. Is 2mm for 99% of printers. Is represented by the number before the "GT", "MR", or "MGT" in the belt part number.
MR: Represents a GT2 belt
MGT: Represents a GT2 or GT3 belt
Tooth Shape/Profile
For Genuine Gates parts, in 2mm pitch specifically, 2GT and GT2 share the same tooth shape. As a result, a GT2 belt can be used on a 2GT pulley and or a 2GT belt on a GT2 pulley, without adverse effects.
Again only in terms of 2mm tooth pitch, GT2 and GT3 also have identical tooth shape. In tooth pitches other than the 2mm we use in 3D printing the situation changes. For example, 3mm pitch belt 3MGT(GT3) and 3GT have different tooth shapes. Additionally, 5mm pitch belt 5MGT(GT3) and 5GT have different tooth shapes.
A comparison of GT, GT2, and GT3 belts.
Belt Construction/Materials
2GT, GT2, and GT3 belts have differing construction/materials. We carry fiberglass reinforced 2GT belt in RF (rubber-fiberglass) and EPDM (ethylene propylene diene monomer). RF belts are rated for use from -35℃ to 80℃ while EPDM belts offer improved performance and heat resistance with temperature ratings of -45℃ to 135℃.
Again only in terms of 2mm tooth pitch, GT3 has identical tooth shape and belt construction to GT2. In other tooth pitches, GT3 has better belt construction/materials than GT2.
Gates US vs Gates Unitta & more background information
GT2 and GT3 belt/pulleys are made in the US [edit: and other regions, see edit below] from locally sourced materials. 2GT belts are made by Gates Unitta in China and Japan with materials sourced locally to them.
Gates and Gates Unitta are partner / sister companies. Both technology and products are shared between the companies. Not all products from each company are distributed by each other. Not all products are interchangeable, but products that differ are generally designated differently so not to be confused. Unitta products are generally intended to service Asian markets, but can be found globally.
There is a lot of confusion about “GT” and “MGT” systems around the world. Joint efforts from Gates USA and Unitta yielded two different system designs. Gates originally named their system PowerGrip GT with 2MR, 3MR and 5MR belt sections. With the introduction of the improved PowerGrip GT2 product line, Gates renamed the belt sections to 2MGT, 3MGT and 5MGT to share the same nomenclature used with their larger 8MGT and 14MGT belts. Gates later improved belt constructions further with the PowerGrip GT3 introduction, but maintained the same profile design platform used with PowerGrip GT and PowerGrip GT2. Unitta named their belt sections 2GT, 3GT and 5GT. The 2MGT and 2GT sections share the same basic system design, so belt tooth and sprocket groove profiles are identical.
Notes/sources:
There are many knockoff suppliers of 2GT and GT2 parts, especially on Amazon/Aliexpress. All bets are off for non-genuine parts. To continue the confusion, some 3d printer vendors sell MXL profile pulleys and idlers as 2GT or GT2. MXL is a trapezoidal profile and has a pitch of 2.03mm. Using 2GT belts with MXL pulleys or vice versa makes for significant vertical 2mm artifacts in prints. The best way to inspect a pulley or idler is to pop off the flange and look at the tooth profile. MXL has a noticeably squared off profile vs continuous curves with 2GT.
EDIT 8/28/23 - per conversations with a Gates US engineer, it has come up that Gates subsidiaries/partners in Europe and Asia produce GT3 belt as well, using locally sourced materials, with similar but not identical performance to US-made GT3 belting.
All of the information above came from Gates engineers, who can be reached at ptpasupport@gates.com. If you have questions, corrections, or more information, please feel free to reach out to us.
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