Timing Belt Identification & Replacement Guide

Downloadable/printable Timing Belt Identification and Replacement (.pdf)

The first step in identifying which timing belt that you have is to look for identifying numbers and/or letters marked on the timing belt. These numbers indicate a standard trade size and will help in identifying the specifics of the cog belt. Also, by being able to identify the manufacturer and/or trade name on the timing belt will assist in the identification process. Common synchronous belt manufacturers include:

• Bando
• Brecoflex
• Carlisle Power Transmission Products
• Continental ContiTech
• Elatech
• FN Sheppard
• Forbo Siegling
• Gates
• Goodyear Engineered Products (Veyance)
• Habasit
• Jason
• Mectrol (Gates)
• Megadyne
• Mitsuboshi Belting, Ltd.
• Optibelt Power Transmission
• U.S.A. Drives, Inc.

Secondly, if there is no trade size indicated on the timing belt do the following:

• Measure the width of the timing belt
• Note the construction of the timing belt. Rubber construction is extremely flexible while a polyurethane construction is plastic like and has little flexibility
• Measure the pitch (see diagram). This is the distance in millimeters (mm) and/or inches between the center of the crown of one tooth and the center of the crown of the tooth adjacent to it.

Downloadable/printable Timing Belt Tooth Profiles and Pitches (.pdf)

• Note the shape of the timing belt pulley teeth (tooth profile); if the valley between the teeth is curved than it is an HTD style timing belt. If the valley between the teeth is flat than it is and PolyChain GT style timing belt. You should also look for identifying numbers and/or letters on the pulleys themselves to help in the timing belt tooth profile identification.

• Count the number of teeth on the timing belt. I suggest marking one tooth on the timing belt with some sort of identification so that you have a starting point for the tooth count. You can also measure the length of the timing belt from end to end if the belt is broken. If the timing belt is in place measure the circumference of the timing belt (distance around the outside edge of the timing belt)

From these pieces of information a replacement timing belt can be identified.

Lastly, if you are changing any of the timing belt pulleys in the power transmission drive than the timing belt length is more than likely to change also. The following information will be needed to determine the correct timing belt length

• Center to center distance between the shaft the driver pulley is fixed to and the shaft the driven pulley is fixed to. This measurement is taken from the center of the shafts. There should be two (2) measurements for this since the majority of timing belt drives has a means in place for tensioning the belts. The two distances required will have one of the shafts in the all the way forward position and the other in the all the way backward position.
  • Center to center distance all the way FORWARD
  • Center to center distance all the way BACKWARD
• Count the number of teeth on both timing belt pulleys. I suggest marking one tooth on the timing belt pulleys with some sort of identification so that you have a starting point for the tooth count

From these pieces of information a replacement timing belt can be identified.