# GT2 timing pulleys 18T to 60T: pitch and outside diameter, flange, bores 5 / 6 / 8 mm, 6 and 9 mm belts (+ 64 to 80T diameters)

> What are the pitch diameter, outside diameter and flange size of a GT2 (2GT) timing pulley, and what bore does each tooth count come in?

- Category: Hardware › Bearings, rails & motion
- Kind: Standard part
- Basis: Misumi 2GT pulley table (PD, OD, F, belt-width block, bores) checked against PD = 2 N / pi and OD = PD − 0.508; SDP/SI cross-check; Misumi linked for CAD
- Page: https://xemstudio.com/objects/gt2-timing-pulleys-18-60t-bores/ · JSON: https://xemstudio.com/api/geometry?object=gt2-timing-pulleys-18-60t-bores · Plain text: https://xemstudio.com/objects/gt2-timing-pulleys-18-60t-bores/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- GT2 (2GT, 2 mm pitch): pitch diameter PD = teeth x 2 / pi and outside diameter OD = PD − 0.508 mm (pitch-line differential 0.254 mm). Misumi's 2GT table (14 to 60 teeth) is the source of the first 21 rows; PD and OD of every one of them agree with that rule to rounding (checked in the generator). Rows for 64 to 80 teeth (bottom) are the same rule, not a maker table: Misumi stops at 60T, so no flange Ø is given for them.
- F is Misumi's flange diameter (its flange-cut rule reads FC >= OD + 1 and FC <= F − 2). Misumi's belt-width block prints three numbers per belt width: A, W and L = belt 4 mm (GT2040): A 5.0, W 8.3, L 16.0; belt 6 mm (GT2060): A 7.0, W 10.3, L 18.0; belt 9 mm (GT2090): A 10.0, W 13.3, L 21.0. The text read does not define A, W or L; the files use A as the width of the toothed section (it is 1 mm more than the belt on all three belts). SDP/SI's 60T / 9 mm belt / 6 mm bore pulley prints PD 38.2, OD 37.7, hub Ø31 and overall length 21.4, the same PD and OD.
- Bore: the last column is the first range printed in Misumi's bore-selection grid for that tooth count (a text extraction of a table, so ranges can be off by a column). 5 mm only reaches 30T there; 16T is listed with 3 and 4 mm bores only (the existing gt2-pulleys page has a 16T / 5 mm bore file).
- Files: 23 pulleys, 18T to 60T, for 6 mm belts (tooth section 7 mm) and 9 mm belts (10 mm), bores Ø5, Ø6 and Ø8 where Misumi's range allows them. Each is a toothed ring with a flange Ø F on both sides and a plain bore at the nominal diameter. Tooth form: round grooves (the same approximation as the gt2-pulleys page), NOT the Gates profile, which is not published; use it for clearance and fit, not belt-grade meshing. Flange thickness 1 mm is an example. No hub, no set-screw holes: the hub diameter is not in the text read.
- Left out: the 10 mm belt width (no table read gives its pulley widths), 16T and 61 to 80T files (no flange Ø in the sources), hubs and set screws, 14 / 15 / 21 / 22 / 25 / 26 / 28 / 32 / 34 / 38 / 44 / 50T (in the table, no file).

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| bore | plain bore at Ø5, Ø6 or Ø8 (the b number in the file name) | motor or idler shaft of the same Ø (set screws / clamp are yours: no hub or tapped hole is drawn) | slide | gt2-* |
| tooth pitch and tooth width | 2 mm pitch; tooth section 7 mm wide (w6 files, 6 mm belt) or 10 mm (w9 files, 9 mm belt) | GT2 / 2GT closed-loop or open belt of that width | designed | gt2-* |
| flange diameter | Misumi F: 16 (18T), 17 (20T), 20 (24T), 24 (30T), 27 (36T), 30 (40T), 35 (48T), 42 (60T) | belt edge guide: the belt rides between the flanges | designed | gt2-* |

## Sizes

| teeth | pitch Ø PD, mm | outside Ø OD, mm | flange Ø F, mm | bore range, mm (plain bore) |
|---|---|---|---|---|
| 14 | 8.91 | 8.40 | 13 | 3 |
| 15 | 9.55 | 9.04 | 14 | 3 to 4 |
| 16 | 10.19 | 9.68 | 14 | 3 to 4 |
| 18 | 11.46 | 10.95 | 16 | 4 to 5 |
| 20 | 12.73 | 12.22 | 17 | 4 to 6 |
| 21 | 13.37 | 12.86 | 18 | 4 to 6 |
| 22 | 14.01 | 13.50 | 18 | not in the text read |
| 24 | 15.28 | 14.77 | 20 | 5 to 8 |
| 25 | 15.92 | 15.41 | 20 | 5 to 8 |
| 26 | 16.55 | 16.04 | 21 | 5 to 8 |
| 28 | 17.83 | 17.32 | 23 | 5 to 10 |
| 30 | 19.10 | 18.59 | 24 | 5 to 11 |
| 32 | 20.37 | 19.86 | 25 | 5 to 13 |
| 34 | 21.65 | 21.14 | 27 | 6 to 14 |
| 36 | 22.92 | 22.41 | 27 | 6 to 14 |
| 38 | 24.19 | 23.68 | 29 | 6 to 16 |
| 40 | 25.46 | 24.95 | 30 | 6 to 17 |
| 44 | 28.01 | 27.50 | 32 | 6 to 19 |
| 48 | 30.56 | 30.05 | 35 | 8 to 22 |
| 50 | 31.83 | 31.32 | 36 | 8 to 23 |
| 60 | 38.20 | 37.69 | 42 | 8 to 29 |
| 64 | 40.74 | 40.24 | — | — |
| 68 | 43.29 | 42.78 | — | — |
| 70 | 44.56 | 44.06 | — | — |
| 72 | 45.84 | 45.33 | — | — |
| 80 | 50.93 | 50.42 | — | — |

## Where the files are

- Misumi (catalog PDF, Mexico site): [2GT high torque timing pulleys: teeth, pitch diameter, outside diameter, flange F, belt-width block A / W / L, bore selection (CAD from Misumi's configurator)](https://mx.misumi-ec.com/en/pdf/fa/2019/2019_MX_1340.pdf) — web — Publisher's page; dimensions are facts
- SDP/SI: [A 6A51M060DF0906: 60-groove 2 mm (GT2) pulley, 9 mm belt, 6 mm bore: PD 38.2, OD 37.7, hub 31, overall length 21.4](https://shop.sdp-si.com/a-6a51m060df0906.html) — web — Publisher's page; dimensions are facts
- Pfeifer Industries: [Timing belt pulley PD / OD charts: PD = pitch x teeth / pi, OD = PD - 2 U (U = cord to tooth root)](https://www.pfeiferindustries.com/information.php?info_id=12) — web — Publisher's page; dimensions are facts

## Free STEP/STL (23 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/index.json

- gt2-18t-b5-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-18t-b5-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-18t-b5-w6.stl) — GT2 18T pulley for a 6 mm belt, bore Ø5: tooth section 7 wide (Misumi's belt-width block), flanges Ø16 (Misumi F) x 1 thick (example), PD 11.46, OD 10.95; approximate round-groove tooth form, no hub, no set screws
- gt2-20t-b5-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-20t-b5-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-20t-b5-w6.stl) — GT2 20T pulley for a 6 mm belt, bore Ø5: tooth section 7 wide (Misumi's belt-width block), flanges Ø17 (Misumi F) x 1 thick (example), PD 12.73, OD 12.22; approximate round-groove tooth form, no hub, no set screws
- gt2-20t-b6-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-20t-b6-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-20t-b6-w6.stl) — GT2 20T pulley for a 6 mm belt, bore Ø6: tooth section 7 wide (Misumi's belt-width block), flanges Ø17 (Misumi F) x 1 thick (example), PD 12.73, OD 12.22; approximate round-groove tooth form, no hub, no set screws
- gt2-24t-b5-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-24t-b5-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-24t-b5-w6.stl) — GT2 24T pulley for a 6 mm belt, bore Ø5: tooth section 7 wide (Misumi's belt-width block), flanges Ø20 (Misumi F) x 1 thick (example), PD 15.28, OD 14.77; approximate round-groove tooth form, no hub, no set screws
- gt2-24t-b6-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-24t-b6-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-24t-b6-w6.stl) — GT2 24T pulley for a 6 mm belt, bore Ø6: tooth section 7 wide (Misumi's belt-width block), flanges Ø20 (Misumi F) x 1 thick (example), PD 15.28, OD 14.77; approximate round-groove tooth form, no hub, no set screws
- gt2-24t-b8-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-24t-b8-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-24t-b8-w6.stl) — GT2 24T pulley for a 6 mm belt, bore Ø8: tooth section 7 wide (Misumi's belt-width block), flanges Ø20 (Misumi F) x 1 thick (example), PD 15.28, OD 14.77; approximate round-groove tooth form, no hub, no set screws
- gt2-30t-b5-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b5-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b5-w6.stl) — GT2 30T pulley for a 6 mm belt, bore Ø5: tooth section 7 wide (Misumi's belt-width block), flanges Ø24 (Misumi F) x 1 thick (example), PD 19.10, OD 18.59; approximate round-groove tooth form, no hub, no set screws
- gt2-30t-b6-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b6-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b6-w6.stl) — GT2 30T pulley for a 6 mm belt, bore Ø6: tooth section 7 wide (Misumi's belt-width block), flanges Ø24 (Misumi F) x 1 thick (example), PD 19.10, OD 18.59; approximate round-groove tooth form, no hub, no set screws
- gt2-30t-b8-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b8-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b8-w6.stl) — GT2 30T pulley for a 6 mm belt, bore Ø8: tooth section 7 wide (Misumi's belt-width block), flanges Ø24 (Misumi F) x 1 thick (example), PD 19.10, OD 18.59; approximate round-groove tooth form, no hub, no set screws
- gt2-36t-b6-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-36t-b6-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-36t-b6-w6.stl) — GT2 36T pulley for a 6 mm belt, bore Ø6: tooth section 7 wide (Misumi's belt-width block), flanges Ø27 (Misumi F) x 1 thick (example), PD 22.92, OD 22.41; approximate round-groove tooth form, no hub, no set screws
- gt2-36t-b8-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-36t-b8-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-36t-b8-w6.stl) — GT2 36T pulley for a 6 mm belt, bore Ø8: tooth section 7 wide (Misumi's belt-width block), flanges Ø27 (Misumi F) x 1 thick (example), PD 22.92, OD 22.41; approximate round-groove tooth form, no hub, no set screws
- gt2-40t-b6-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-40t-b6-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-40t-b6-w6.stl) — GT2 40T pulley for a 6 mm belt, bore Ø6: tooth section 7 wide (Misumi's belt-width block), flanges Ø30 (Misumi F) x 1 thick (example), PD 25.46, OD 24.96; approximate round-groove tooth form, no hub, no set screws
- gt2-40t-b8-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-40t-b8-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-40t-b8-w6.stl) — GT2 40T pulley for a 6 mm belt, bore Ø8: tooth section 7 wide (Misumi's belt-width block), flanges Ø30 (Misumi F) x 1 thick (example), PD 25.46, OD 24.96; approximate round-groove tooth form, no hub, no set screws
- gt2-48t-b8-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-48t-b8-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-48t-b8-w6.stl) — GT2 48T pulley for a 6 mm belt, bore Ø8: tooth section 7 wide (Misumi's belt-width block), flanges Ø35 (Misumi F) x 1 thick (example), PD 30.56, OD 30.05; approximate round-groove tooth form, no hub, no set screws
- gt2-60t-b8-w6: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-60t-b8-w6.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-60t-b8-w6.stl) — GT2 60T pulley for a 6 mm belt, bore Ø8: tooth section 7 wide (Misumi's belt-width block), flanges Ø42 (Misumi F) x 1 thick (example), PD 38.20, OD 37.69; approximate round-groove tooth form, no hub, no set screws
- gt2-20t-b5-w9: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-20t-b5-w9.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-20t-b5-w9.stl) — GT2 20T pulley for a 9 mm belt, bore Ø5: tooth section 10 wide (Misumi's belt-width block), flanges Ø17 (Misumi F) x 1 thick (example), PD 12.73, OD 12.22; approximate round-groove tooth form, no hub, no set screws
- gt2-20t-b6-w9: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-20t-b6-w9.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-20t-b6-w9.stl) — GT2 20T pulley for a 9 mm belt, bore Ø6: tooth section 10 wide (Misumi's belt-width block), flanges Ø17 (Misumi F) x 1 thick (example), PD 12.73, OD 12.22; approximate round-groove tooth form, no hub, no set screws
- gt2-30t-b5-w9: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b5-w9.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b5-w9.stl) — GT2 30T pulley for a 9 mm belt, bore Ø5: tooth section 10 wide (Misumi's belt-width block), flanges Ø24 (Misumi F) x 1 thick (example), PD 19.10, OD 18.59; approximate round-groove tooth form, no hub, no set screws
- gt2-30t-b6-w9: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b6-w9.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b6-w9.stl) — GT2 30T pulley for a 9 mm belt, bore Ø6: tooth section 10 wide (Misumi's belt-width block), flanges Ø24 (Misumi F) x 1 thick (example), PD 19.10, OD 18.59; approximate round-groove tooth form, no hub, no set screws
- gt2-30t-b8-w9: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b8-w9.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-30t-b8-w9.stl) — GT2 30T pulley for a 9 mm belt, bore Ø8: tooth section 10 wide (Misumi's belt-width block), flanges Ø24 (Misumi F) x 1 thick (example), PD 19.10, OD 18.59; approximate round-groove tooth form, no hub, no set screws
- gt2-40t-b6-w9: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-40t-b6-w9.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-40t-b6-w9.stl) — GT2 40T pulley for a 9 mm belt, bore Ø6: tooth section 10 wide (Misumi's belt-width block), flanges Ø30 (Misumi F) x 1 thick (example), PD 25.46, OD 24.96; approximate round-groove tooth form, no hub, no set screws
- gt2-40t-b8-w9: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-40t-b8-w9.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-40t-b8-w9.stl) — GT2 40T pulley for a 9 mm belt, bore Ø8: tooth section 10 wide (Misumi's belt-width block), flanges Ø30 (Misumi F) x 1 thick (example), PD 25.46, OD 24.96; approximate round-groove tooth form, no hub, no set screws
- gt2-60t-b8-w9: [STEP](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-60t-b8-w9.step) · [STL](https://xemstudio.com/files/hardware/gt2-timing-pulleys-18-60t-bores/gt2-60t-b8-w9.stl) — GT2 60T pulley for a 9 mm belt, bore Ø8: tooth section 10 wide (Misumi's belt-width block), flanges Ø42 (Misumi F) x 1 thick (example), PD 38.20, OD 37.69; approximate round-groove tooth form, no hub, no set screws

## Questions

**What is the outside diameter of a 20 tooth GT2 pulley?**

12.22 mm (pitch diameter 12.73 mm, OD = PD − 0.508); Misumi's flange is Ø17.

**What is the diameter of a 60 tooth GT2 pulley?**

PD 38.20 mm, OD 37.69 mm, flange Ø42 (Misumi).

**What is the diameter of an 80 tooth GT2 pulley?**

PD 50.93 mm, OD 50.42 mm by the PD − 0.508 rule; no maker flange size was read for 80T.

**What bores do GT2 pulleys come in?**

Misumi's grid: 5 mm bores up to 30T, 6 mm from 20T, 8 mm from 24T; larger tooth counts take larger bores (60T up to 29 mm).

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