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Narrow V-belts 3V, 5V, 8V and SPZ, SPA, SPB, SPC (wedge belts): top width, height, datum width and length designation
What are the width and height of an SPZ, SPA, SPB, SPC, 3V, 5V or 8V V-belt, and how are they sized (datum length mm or outside length in tenths of an inch)? · Standard part · basis: Optibelt (ISO 4184 / ISO 4183 narrow sections), Gates, Dayco, VBeltSupply, Tameson and GPR Industrial; sources disagree by up to 1 mm and all are shown; numbers only
Also called: spz belt dimensions, spa belt dimensions, spb belt dimensions, spc belt dimensions, 3v belt width, 5v belt width, 8v belt width, 3v vs spz belt, 5v vs spb belt, narrow v belt size chart, wedge belt cross section, spb belt 16.3 x 13, spz belt 9.7 x 8, 3v250 belt length, v belt datum length spz, optibelt spa belt width
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. Mating features
- sizes
- 7 in table
Notes
- Narrow (wedge) V-belts carry more power in less width than classical belts. Metric sections SPZ, SPA, SPB, SPC (ISO 4184 narrow) are designated by the datum length Ld in mm; the US sections 3V, 5V, 8V (RMA IP-20; 9N, 15N, 25N in Optibelt's naming) are designated by outside length in tenths of an inch (3V250 is 25.0 in). SPZ and 3V, SPB and 5V are close in size but are different belts and different grooves: they are not interchangeable.
- Where the sources disagree (they do, by up to 1 mm in top width): Optibelt's table, which follows ISO 4184, prints SPZ 9.7, SPA 12.7, SPB 16.3 and SPC 22 mm wide; Gates' catalogue, VBeltSupply and GPR Industrial print the rounded 10, 13, 17, 22 mm; Tameson prints 9.7 / 12.7 / 17 / 22. For 3V / 5V / 8V: Optibelt 9 / 15 / 25 × 8 / 13 / 23, Gates 10 / 17 / 26 × 8 / 13 / 23 (printed as SPZ-3V, SPB-5V, 8V), Dayco 3V 9.5 × 8, VBeltSupply 3/8 / 5/8 / 1 in wide and 21/64 / 35/64 / 7/8 in high, Tameson 9.7 / 15.8 / 25.4 × 8 / 14 / 23. Heights agree within 1 mm. All the numbers are shown; none is chosen as 'the' size.
- Datum width (wd) is the groove width at the datum line from ISO 4183, as used on the pulley-groove page (SPZ 8.5, SPA 11, SPB 14, SPC 19 mm); 3V, 5V and 8V sheaves follow RMA / MPTA groove tables, which are not tabulated here. Aims Industrial prints inside-to-pitch length additions for the narrow metric sections: SPZ 13 mm, SPA 18 mm, SPB 22 mm, SPC 30 mm (single source; use your maker's table). Gates' Powerband catalogue prints 3V / 5V / 8V rib pitches of 10.30, 17.50 and 28.60 mm and SPB / SPC 19.00 and 25.50 mm for banded belts.
- Groove / belt angle: Aims Industrial states a 40° belt angle for A and SPZ; a US belt retailer describes SP belts with a 38° wedge angle (that is the ISO 4183 pulley-groove angle for larger diameters, not the belt angle). No angle is tabulated here for that reason.
- Not on this page: banded (Powerband) widths, cogged raw-edge (XPZ, XPA, XPB, 3VX, 5VX) variations, tolerances and matching, belt length tables, minimum sheave diameters. McMaster-Carr's V-belt category is linked below for per-belt CAD.
Narrow V-belts 3V, 5V, 8V and SPZ, SPA, SPB, SPC (wedge belts): top… size chart
| section | Optibelt / ISO, top width × height, mm | Gates, mm | Dayco / VBeltSupply inch (mm in brackets) | Tameson, mm | datum width wd, mm (ISO 4183) | length designation |
|---|---|---|---|---|---|---|
| SPZ | 9.7 × 8 | 10 × 8 (listed with 3V) | 10 × 8 mm (VBeltSupply) | 9.7 × 8 | 8.5 | datum length Ld, mm (e.g. SPZ 767) |
| SPA | 12.7 × 10 | 13 × 10 | 13 × 10 mm (Dayco, VBeltSupply) | 12.7 × 10 | 11 | datum length Ld, mm |
| SPB | 16.3 × 13 | 17 × 13 (listed with 5V) | 17 × 13 mm (VBeltSupply) | 17 × 13 | 14 | datum length Ld, mm |
| SPC | 22 × 18 | 22 × 18 | 22 × 18 mm (VBeltSupply) | 22 × 18 | 19 | datum length Ld, mm |
| 3V / 9N | 9 × 8 (9N) | 10 × 8 (listed with SPZ) | 3/8 × 21/64 in (VBeltSupply, 9.5 × 8.3); 9.5 × 8 mm (Dayco) | 9.7 × 8 | — | outside length in tenths of an inch (3V250 = 25.0 in; Dayco 3V250DR 25.00 in) |
| 5V / 15N | 15 × 13 (15N) | 17 × 13 (listed with SPB) | 5/8 × 35/64 in (VBeltSupply, 15.9 × 13.9) | 15.8 × 14 | — | outside length in tenths of an inch (5V620 = 62.0 in, VBeltSupply) |
| 8V / 25N | 25 × 23 (25N) | 26 × 23 | 1 × 7/8 in (VBeltSupply, 25.4 × 22.2) | 25.4 × 23 | — | outside length in tenths of an inch |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance (tolerances by process); leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| datum width wd (SPZ / SPA / SPB / SPC) | 8.5 / 11 / 14 / 19 mm | pulley groove datum width wd (ISO 4183): see v-belt-pulley-grooves-iso-4183-narrow | designed | all |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
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=v-belts-narrow-3v-5v-8v-spz-spa-spb-spc
Fits with
Questions
How wide is an SPB belt?
16.3 mm per ISO 4184 (Optibelt); 17 mm in Gates, VBeltSupply and Tameson; 13 mm high; datum width 14 mm.
Is a 3V belt the same as an SPZ belt?
No. They are close (about 9.5 to 10 mm wide, 8 mm high) but are different standards with different grooves; sources print 3V as 9, 9.5, 9.7 or 10 mm wide.
How is a 5V belt length given?
Outside length in tenths of an inch: 5V620 is 62.0 in around the outside.