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Timing belt profiles: GT2, HTD 3M / 5M / 8M, T5, T10, AT5, MXL, XL, L, H: pitch, tooth height and pulley pitch diameter
What is the pitch of a GT2, HTD 3M, 5M, 8M, T5, T10, AT5, MXL, XL or L timing belt, and what is the pitch diameter of a pulley with N teeth? · Standard part · basis: Texas Belting pitch chart for pitch and tooth height, optibelt ISO 5296 numbers for XL / L / H, York Industries for MXL / XL / L pitch; pitch diameter computed as N × pitch / π
Also called: gt2 belt pitch, htd 5m pitch, htd 3m belt dimensions, htd 8m pitch, t5 belt pitch, t10 belt pitch, at5 vs t5, mxl belt pitch, xl belt pitch 0.200, l belt pitch 3/8, timing belt pitch chart, timing pulley pitch diameter, timing pulley diameter formula, gt2 vs htd 3m, iso 5296 belt, belt tooth height, 5m vs t5, timing pulley 20 tooth diameter
Exact dimensions. True size, with no tolerance added.
- sizes
- 13 in table
Notes
- Pitch is the distance between belt tooth centres along the pitch line; a pulley with N teeth has pitch Ø = N × pitch / π (a definition, so the last three columns are computed: 20 teeth of 2 mm pitch is 12.73 mm; 20 teeth of 5 mm is 31.83 mm). The pulley's outside diameter is the pitch Ø minus twice the pitch-line differential of the profile; the differentials (for example GT2's 0.254 mm, already on the gt2-pulleys page) were not readable in any table reached for the other profiles, so no OD column is given.
- Table sources: pitch and tooth height of all thirteen profiles come from Texas Belting's pitch chart (a distributor; belt thickness is printed there only for HTD 3M / 5M / 8M). XL, L and H are ISO 5296 profiles and optibelt prints the standard numbers: overall belt thickness hs (2.3, 3.6, 4.0), tooth height ht (1.27, 1.91, 2.29), tooth angle 2β (50°, 40°, 40°), tooth width s (2.57, 4.65, 6.12) and foot / head radii (0.38, 0.51, 1.02). York Industries confirms the MXL, XL and L pitches (0.080, 0.200, 0.375 in).
- Disagreement: H profile tooth height is 2.54 mm (0.100 in) at Texas Belting and 2.29 mm at optibelt; both are shown. XL and L agree (1.27 / 1.91). MXL 2.032 mm is 0.080 in. Other profiles: tooth heights for T2.5, T5, AT5, T10, AT10, GT2 and HTD have one source only.
- Same pitch does not mean same belt: T5 and HTD 5M are both 5 mm pitch but their tooth heights are 1.2 and 2.1 mm, and 2 mm (GT2), 2.5 mm (T2.5) and 3 mm (HTD 3M) belts are listed as separate profiles. ISO 5296 covers the MXL, XL, L, H, XH and XXH profiles (optibelt).
- No tooth-profile files: only XL, L and H have a tooth angle / width / radii here, and the pulley groove (not the belt tooth) is what a drawing needs, which no table read gave. GT2 pulleys with an approximate tooth form are on the gt2-pulleys page and are labelled approximate there.
- Not tabulated: pitch-line differentials, minimum teeth, belt widths per profile (Texas Belting lists a width range per profile), width codes (e.g. 025 = 1/4 in for XL) and pulley flange sizes. Gates / SDP-SI / Misumi / optibelt publish them; none was readable here.
Timing belt profiles: GT2, HTD 3M / 5M / 8M, T5, T10, AT5, MXL, XL… size chart
| profile | pitch, mm | pitch, in | tooth height, mm | belt thickness, mm | tooth angle 2β (ISO 5296) | tooth width s, mm | foot / head radius, mm | pitch Ø of 20 teeth, mm | pitch Ø of 30 teeth, mm | pitch Ø of 40 teeth, mm |
|---|---|---|---|---|---|---|---|---|---|---|
| MXL | 2.032 | 0.08 | 0.51 | — | — | — | — | 12.94 | 19.40 | 25.87 |
| GT2 (2 mm) | 2 | 0.0787 | 0.75 | — | — | — | — | 12.73 | 19.10 | 25.46 |
| T2.5 | 2.5 | 0.0984 | 0.7 | — | — | — | — | 15.92 | 23.87 | 31.83 |
| HTD 3M | 3 | 0.1181 | 1.2 | 2.4 | — | — | — | 19.10 | 28.65 | 38.20 |
| T5 | 5 | 0.1969 | 1.2 | — | — | — | — | 31.83 | 47.75 | 63.66 |
| HTD 5M | 5 | 0.1969 | 2.1 | 3.8 | — | — | — | 31.83 | 47.75 | 63.66 |
| AT5 | 5 | 0.1969 | 1.2 | — | — | — | — | 31.83 | 47.75 | 63.66 |
| XL | 5.08 | 0.2 | 1.27 | 2.3 (optibelt) | 50° | 2.57 | 0.38 / 0.38 | 32.34 | 48.51 | 64.68 |
| HTD 8M | 8 | 0.315 | 3.4 | 5.6 | — | — | — | 50.93 | 76.39 | 101.86 |
| L | 9.525 | 0.375 | 1.91 | 3.6 (optibelt) | 40° | 4.65 | 0.51 / 0.51 | 60.64 | 90.96 | 121.28 |
| T10 | 10 | 0.3937 | 2.5 | — | — | — | — | 63.66 | 95.49 | 127.32 |
| AT10 | 10 | 0.3937 | 2.5 | — | — | — | — | 63.66 | 95.49 | 127.32 |
| H | 12.7 | 0.5 | 2.54 (optibelt 2.29) | 4 (optibelt) | 40° | 6.12 | 1.02 / 1.02 | 80.85 | 121.28 | 161.70 |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Texas Belting | Timing belt pitch chart: pitch and tooth height for MXL, GT2, T2.5, 3M, T5, 5M, AT5, XL, 8M, L, T10, AT10, H, 14M, XH, XXH | web | Publisher's page; dimensions are facts |
| optibelt | ZR rubber timing belt drives technical data (ISO 5296): XL / L / H pitch, thickness hs, tooth height ht, tooth angle 2β, tooth width s, radii | web | Publisher's page; dimensions are facts |
| York Industries | Synchronous drive specifications: MXL 0.080 in, XL 0.200 in, L 0.375 in pitch | web | Publisher's page; dimensions are facts |
Xem scan
File coming
No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.
https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.Plain text: sheet.txt · JSON: /api/geometry?object=timing-belt-profiles-pitch-and-tooth
Fits with
Questions
What is the pitch of GT2, HTD 3M, HTD 5M and HTD 8M belts?
2 mm, 3 mm, 5 mm and 8 mm. They are named for the pitch in millimetres.
What is the pitch diameter of a 20 tooth GT2 pulley?
20 × 2 mm / π = 12.73 mm; the outside diameter is 0.508 mm smaller (gt2-pulleys page).
Is T5 the same as HTD 5M?
No: both have 5 mm pitch but different tooth heights (1.2 and 2.1 mm), so they are different profiles.
What is the pitch of an XL belt?
0.200 in (5.08 mm); L is 0.375 in (9.525 mm), MXL 0.080 in (2.032 mm), H 0.500 in (12.7 mm).