Metric V-belt Lengths

Depending on the belt type and the manufacturer, metric V-Belt part number may specify different length measurements. The different belt lengths, abbreviations, and their relative positions in the belt are:



Gates classical Metric Power™ V-belts (e.g 10X, 13X, 17X) specify inside length in millimeters followed by”Li”. Narrow Gates Metric Power V-belts (e.g. SPZ, SPA, SPB, SPC) specify the datum/pitch length in millimeters.

Converting one length type into another may be required to identify if a proper replacement belt exists. The following table converts between any of the four length measurements. To find the correct equation, read the column headings across the top and choose the appropriate belt cross section. Read down the rows at the left and select the belt length type to calculate. Reading down the selected column and across the selected row, the box at the intersection lists the equations to convert from any of the other three length types.

Using Extra Wide Driven Sprockets and Sheaves to Increase Bore Ranges

Hardware component selections for normal belt drives use the same widths for both the driver and driven sprockets or sheaves.   This looks normal and works well most of the time.

But what if the driven shaft diameter is unusually large and exceeds the bore range of the selected driven sprocket or sheave?  One option is to re-design and select hardware components with larger bore ranges.  Another option is to consider using a driven component in the same diameter, but in a wider width than necessary.

For example, an 8MX-140S-12 sprocket uses a 2012 bushing with a maximum bore of 2.125”.  An 8MX-140S-21 sprocket uses a 2517 bushing with a maximum bore of 2.688”.  In this case, just using a sprocket with a 21mm face width instead of a 12mm face width will increase the sprocket bore range from 2.125” to 2.688”, which is considerable.  This principle can apply to other sprocket, pulley and sheave types as well.

With synchronous belt drives there is no harm in using wider driven sprockets so long as the driver sprocket is double flanged so the belt is constrained appropriately on both sides.  A wider driven sprocket may look unusual, but will function just fine.  And the parallel sprocket alignment isn’t as critical with the wider sprocket face width.

With V-belt drives there is no harm in using wider driven sheaves.  There may be some empty sheave grooves in the wider driven sheave, but this will not pose any problems.  Just be sure to accurately align the driver sheave grooves with the driven sheave grooves that will contain V-belts.

For questions or further information, contact Gates Product Application Engineering at 303-744-5800 or at ptpasupport@gates.com

Will It Fit - HTD Sprockets

What belt will fit into what industry standard sprocket is a question we regularly receive here in Product Application.  Below is information regarding what Gates belts will fit into standard HTD sprockets.  

** Please note:  When designing belt drives for new applications with PowerGrip GT3 power raitings, DO NOT use HTD sprocket systems.  HTD sprockets and bushings may not be able to handle the increased torque loads and damage to the sprocket and/or bushing may occur.  Only Use PowerGrip GT2 sprockets for new PowerGrip GT2 designs.**

For any additional questions feel free to look through our other blog topics or contact us at ptpasupport@gates.com or 303-744-5800.

Get Your Career Spinning - Gates PT Workshop

We are pleased to announce that Gates now offers power transmission workshops for customers and distributors. Over a two day period our product application team instructs students on the following topics:

Gates Products Overview

Belt Drive Design Basics

Roller Chain Conversions

Energy and Maintenance Savings

Drive Inspection and Troubleshooting

Drive Installation

And more!

For more information and registration please visit http://cms.gates.com/gatesu/home