ConCar Variable Speed Belts 32x10 - 720 Li

ConCar Variable Speed Belts 32x10 – 720 mm inner length – DIN 7719 / ISO 1604

The ConCar Variable Speed Belts with a 32x10 profile and a 720 mm inner length, is an open-flanked, toothed variator belt conforming to DIN 7719 and ISO 1604. It transmits drive power exclusively via its two flanks, moving radially on the conical, axially displaceable pulley halves during operation. This movement is the principle behind a mechanical speed converter: when one pulley closes, it pushes the belt outwards to a larger effective diameter, while on the opposite side it slides inwards. This allows the transmission ratio to change continuously without the need for shifting, clutching, or electronic control.

This length in the drive

The inner length of 720 mm is a short version for the 32x10 profile. This means a compact center distance and a correspondingly small drive volume, but at the same time a high bending frequency. At a belt speed of 20 m/s, this equates to approximately 26.0 revolutions per second. With short belts, check whether the tapered pulleys meet the minimum running diameter specified by the manufacturer, as the bending stress has the greatest impact on service life at this point.

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 720 mm; it is measured at the inner circumference of the belt and is the standard ordering dimension in Germany. The effective length (Ld) of 770 mm refers to the neutral axis and is the dimension used in many catalogs and drive calculations. The outer length (La) of 783 mm is measured at the back of the belt. With a profile height of 10 mm, the difference between the inner and outer lengths is 63 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): 720 mm

• Effective length (Ld): 770 mm

• External length (La): 783 mm

• Profile: 32x10 according to DIN 7719 / ISO 1604

• Top width: 32 mm

• Height: 10 mm

• Flank angle: 27°

• 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: 0.307 kg

• Article number: G432100720

• EAN: 4059213022343

• 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 27° 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, allowing the belt to run smoothly across the entire adjustment range of the pulleys and preventing binding at the end positions. Simultaneously, the large upper width of 32 mm provides the necessary contact area to transmit torque solely through friction. The shaped 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 cover the classic field of industrial variators: feed and grinding belt control in woodworking machines, demand-controlled piston and screw compressors, spinning and drawing units in textile machines, industrial mixers and kneaders with soft start, take-off and screw drives on plastic extruders, as well as boring mills and lathes with stepless control.

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

For installation: Open the pulleys, place the belt on without tension, then adjust it to the required tension using the adjustment mechanism or the motor rocker. The belt must never be pulled over the pulley edge or pried open with a tool. After approximately 24 hours of operation, the belt will have settled; at this point, the tension should be checked a second time and adjusted if necessary. Insufficient tension leads to slippage and burns the belt edges, while excessive tension puts unnecessary stress on the bearings and tension members.

A typical wear pattern in the variator is glassy, ​​shiny edges. This is not a sign of aging, but rather slippage: the belt slips under load and polishes the edge. The cause is almost always insufficient tension or a worn pulley with an enlarged groove width. If only the belt is replaced and the pulley remains the same, the damage usually recurs within a few weeks.

Similar names for other brands

Variable Speed Belts are standardized according to DIN 7719 and ISO 1604. A belt with a 32x10 profile and a 720 mm inner length 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 32x10 / VARIO POWER 32x10

• GATES: Multi-Speed ​​32x10 / Predator V Variable Speed

• CONTITECH: VARIO Speed ​​32x10 / CONTI-V VARISPEED

• MEGADYNE: VARISECT 32x10

• MITSUBOSHI: VARI-SPEED 32x10

• BANDO: Variable Speed ​​32x10

• PIX: Variable Speed ​​32x10

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.