ConCar Variable Speed Belts 65x20 - 2406 Li

ConCar Variable Speed Belts 65x20 – 2,406 mm inner length – DIN 7719 / ISO 1604

The ConCar Variable Speed Belts 65x20 x 2.406 Li is a flank-driven variator belt according to DIN 7719 and ISO 1604 with a molded toothed underside. The transversely molded teeth are not a tooth profile in the sense of a toothed belt; they do not engage with the pulley. Their purpose is to reduce bending stiffness so that the belt can be bent even on small running diameters without the flanks tearing or the belt heating up due to internal flexing.

This length in the drive

The inner length of 2,406 mm is a long version for the 65x20 profile and is intended for drives with a large center distance, approximately 465 mm with two identical pulleys of 500 mm effective diameter. At 3.524 kg, this belt weighs correspondingly more than the shorter lengths of the same profile. With this length, plan for a guide or support for the slack side if the drive operates with highly variable loads, and check the tension again after the initial break-in period.

For design and comparison with an existing belt, the three length specifications are important because manufacturers use different reference dimensions. The inner length (Li) is 2,406 mm; it is measured at the inner circumference of the belt and is the standard ordering dimension in Germany. The effective length (Ld) of 2,501 mm refers to the neutral axis and is the dimension used in many catalogs and drive calculations. The outer length (La) of 2,532 mm is measured at the back of the belt. With a profile height of 20 mm, the difference between the inner and outer lengths is 126 mm, which corresponds to twice the difference in circumference across the belt height. When replacing an old belt, always compare using the same reference dimension; otherwise, you can easily be off by several centimeters.

Dimensions and specifications

• Internal length (Li): 2,406 mm

• Effective length (Ld): 2,501 mm

• External length (La): 2,532 mm

• Profile: 65x20 according to DIN 7719 / ISO 1604

• Top width: 65 mm

• Height: 20 mm

• Flank angle: 30°

• Construction: open-sided, toothed

• Mixture: Chloroprene (CR)

• Tensioning material: Polyester cord

• Antistatic: yes, according to ISO 9563

• Temperature range: -30 °C to +80 °C

• Belt speed: up to 30 m/s

• Weight: 3.524 kg

• Article number: G465202406

• EAN: 4059213024682

• Manufacturer: ConCar

Structure and materials

In terms of materials, ConCar combines a chloroprene body with a polyester tensile member. This pairing is the industry standard for variator belts because it simultaneously fulfills two opposing requirements: The belt must be flexible enough to bend over a small diameter, yet stiff enough longitudinally to resist flexing under load. Antistatic treatment according to ISO 9563 is standard on ConCar belts and is not an additional cost option.

The 30° flank angle is the crucial difference compared to a conventional V-belt, which operates at 34 to 40 degrees. The shallower angle generates less wedging effect per millimeter of radial travel, ensuring smooth belt operation across the entire pulley adjustment range and preventing binding at the end positions. Simultaneously, the large 65 mm upper width provides the necessary contact area to transmit torque solely through friction. The toothed underside reduces bending stiffness to such an extent that the belt can operate even on small effective diameters without the flanks overheating due to internal flexing.

Typical areas of application

Belts of this size are used in heavy-duty drives: threshing and drum drives on combine harvesters, intake and chopping units on forage harvesters, sawing and chipboard plants, large conveying and crushing plants, as well as compressor and blower drives where the speed must follow the demand without shifting a gearbox.

What these applications have in common is that the rotational speed must be adjusted during operation to suit the material, batch, or demand. A Variable Speed Belts solves this problem purely mechanically, without any electronics in the drive train. This is advantageous wherever dust, moisture, vibration, or temperature would damage a frequency converter, and it remains the only economical solution for existing machines because the variator is an integral part of the machine's design.

Assembly and tension

Variable Speed Belts are supplied as continuous, single belts and cannot be shortened or joined. Before installation, the tapered pulleys must be fully opened so that the belt can be positioned at its smallest effective diameter. Tensioning is then achieved via the pulley's adjustment range or the motor rocker arm. Prying the belt open by the pulley edge is particularly damaging with Variable Speed Belts , as this can damage the exposed flanks and the tension member without any visible external damage.

Transverse cracks on the underside indicate an insufficient bearing diameter or cold brittleness, while longitudinal cracks and frayed edges point to misalignment between the pulleys. It's worthwhile checking the alignment with a ruler or laser when changing the belt, as even a few millimeters of misalignment over a one-meter center-to-center distance can halve the belt's lifespan.

Similar names for other brands

Variable Speed Belts are standardized according to DIN 7719 and ISO 1604. A belt with a 65x20 profile and an inner length of 2,406 mm is therefore dimensionally identical regardless of the manufacturer; no modification of the pulleys is required for replacement. This ConCar belt replaces, among others:

• OPTIBELT: VB 65x20 / VARIO POWER 65x20

• GATES: Multi-Speed ​​65x20 / Predator V Variable Speed

• CONTITECH: VARIO Speed ​​65x20 / CONTI-V VARISPEED

• MEGADYNE: VARISECT 65x20

• MITSUBOSHI: VARI-SPEED 65x20

• BANDO: Variable Speed ​​65x20

• PIX: Variable Speed ​​65x20

Delivery

The belt is supplied as a single, endless belt. Standard lengths and common profiles are available from stock; custom lengths and widths are available upon request. If you are unsure which length your drive requires, please send us the part number of your old belt or the dimensions of your pulleys, and we will check the compatibility.