Interchanging Competitive Belts

Interchanging competitive belts can can be a simplified process. This site provides various interchange tools grouped by market and product type.

If a belt replacement is not listed in the interchange, Gates Application Engineers may be able to assist using measured belt dimensions. The number of teeth (synchronous belts only), length, width, and thickness can help the engineers identify the closest standard replacement.

It should be noted that replacing belts based solely on measurements is not ideal. In these cases, Gates cannot guarantee that the materials would be the same or that the belt will provide the same performance level as the original belt.

Belt Drives and Oil Contamination

Belt drive contamination with oil is never beneficial, but sometimes cannot be avoided. While occasional contact does not generally have adverse effects, prolonged contact with oil type lubricants, either directly or airborne, causes rubber compounds to soften and swell. Adhesion systems internal to belts are also weakened and broken down. This ultimately results in significantly reduced belt service life.

V-belt drives rely exclusively on friction to transmit power, so any contaminants that reduce friction also reduce the ability of the belt drive to transmit power. Banded type V-belts might have slightly improved resistance, compared to "raw edge" or "cut edge" type V-belts, with the outside cover temporarily shielding internal components. Also, neoprene based V-belts will have greater resistance to oil than EPDM based V-belts.

Synchronous belt drives rely less on friction to transmit power than V-belt drives. They also tend to perform better in oil contaminated environments. Rubber based synchronous belts, however, are still susceptible to swelling and adhesion system breakdown over time. While alternate rubber compounds may provide some marginal improvement in durability, it is best to prevent oil from contacting rubber synchronous belts if possible.

Gates Poly Chain type belts use a urethane based construction that is quite resistant to oil contamination. This prevents material swelling and breakdown that cannot be avoided with rubber materials. Note that synchronous belts still rely on friction to transmit power, so lubrications will interfere with power transmission. Poly Chain GT Carbon belts are used successfully in environments with heavy misting of oil based lubricants and cutting fluids, and have even been submerged in oil. Poly Chain GT Carbon belts are the best bet for applications that cannot avoid oil contamination.

Micro-V Belts

Gates has a line of belts that we call Micro-V. They are called this because the belt is made up of a band of small V-belts put together. They are also called Poly-V belts by others in the industry. These belts are actually very common, in fact, you may have worked on one, and not even known it! Micro-V belts come in different sizes, or sections. One of these sections is called K-section, this is the type of belt that runs the accessory drives (alternator, water pump, etc…) under the hood of your car. While they are commonly called serpentine because of the way that they move around the pulleys, these are in fact K-section Micro-V belts. K-section belts are mainly used on automobiles and industrial gasoline and diesel motors. The less known sections of Micro-V’s include H, J, L, and M sections. H section is very small, and is typically not used for design except by large OE’s. J , L, and M section belts are the standard industrial line that we can help you design with. These belts push a lot of power for their size, are quiet, and can handle higher speeds well. One thing to keep in mind, however, is that we don’t have any off the shelf pulleys for them. This means that you would either need to have something made to order, or you could contact us for the groove information to create your own pulleys. You can find more information about these belts in our Light Power and Precision Drive Design Manual or as always by contacting us directly.

Water & Synchronous Belt Resistance

Light and occasional contact with water, such as occasional wash downs, should not generally affect synchronous belts seriously. Prolonged contact such as spray or submersion, however, can have detrimental effects.Rubber synchronous belts are considerably more vulnerable than Poly Chain GT Carbon belts.


With rubber synchronous belts, water soaking reduces the tensile strength of fiberglass tensile cords in addition to breaking down adhesion systems between the cord and the rubber compound. While aramid type tensile cords are more resistant to water than fiberglass, they are dimensionally unstable in the presence of water or humidity, so can result in belt length stability problems. Soaking also causes the rubber body to swell, lesser than but similar to oil contamination. This can negatively impact belt pitch fit with pulleys and sprockets in addition to material weakening. Additives to water such as lubricants, chlorine, anti-corrosives, etc. can intensify detrimental affects of water soaking.


Poly Chain GT Carbon belts are quite resistant to water soaking, and have even been used successfully in submerged applications. While urethane can exhibit a small amount of swelling, overall belt performance and the ability to transmit power remains relatively stable.


When considering the use of synchronous belt drive systems in moist or wet environments, the resistance of the hardware to corrosion is also very important. Coatings or treatments used on standard iron based hardware may not have adequate corrosion resistance. Special corrosion resistant coatings such as zinc or nickel plating are available on a made-to-order basis.


Contact our Made-To-Order Metals Group at (800) 709-6001 for further information about hardware corrosion protection options. Contact our Product Application Engineering Group at (303) 744-5800 for further information about applying belt drive systems in adverse environments.

Motorcycle Belts

Customers often contact Gates regarding belts for motorcycle applications. Unfortunately, Gates does not sell motorcycle replacement belts directly to aftermarket users. The best method to obtain a proper replacement belt is to go through the dealer network for the particular brand of motorcycle.

Various aftermarket distributors also service the market, and they serve as an alternate source for replacement belts. However, some motorcycle belts sold through the original dealer network may be manufactured with proprietary constructions not available through aftermarket distributors.

The standard Poly Chain® GT® Carbon™ belts sold by Gates general market distributors have the GT tooth style. These belt are not recommended for use with motorcycle sprockets, which are typically designed with the HTD® tooth style.

Aftermarket distributor can typically assist with custom motorcycle applications. However, belts in lengths other than those available from aftermarket distributors may require new tooling at costs in excess of $25K per mold.

Synchronous Belt Drive - Test for Structural Integrity

Since synchronous belts are a positive drive and do not slip, they will attempt to transmit all the load that is applied. V-belts will slip at peak loads, almost acting as a clutch and as such not passing that peak loading on to the system's structure.

Since synchronous belts will not act as a clutch, it is important to make sure that the drive structure is adequate. This is more of a concern for HVAC type applications, given their structural considerations.

To check for structural rigidy, first make sure that the system is powered off, locked down and tagged out. Never touch or work with any belt system without taking appropriate safety measures.

Then, grab the opposing belt spans and push or squeeze them towards each other. While doing this, keep an eye on the shafts in the system. If you see significant movement or deflection, the system is not an ideal candidate for synchronous belt conversion without further structural strengthening. If you do not see any movement, or minimal movement, the system's structure is adequate and a good candidate for converting to synchronous belts.

Rust Inhibitor - Krown KL 73

Krown KL 73 is a solvent free rust inhibitor and lubricant that is used with metal products to help protect against rust and also to lubricate moving parts. As with any belt drive, it is not recommended to use any lubrication or belt dressing on the drive. Furthermore, KL 73 can be detrimental to the integrity of the rubber used in power transmission V and synchronous belts. Because of this, KL 73 is not recommended to be used as a rust inhibitor on any power transmission sheave or sprocket containing V or synchronous belts. Find more information on Krown KL 73