ConCar Variable Speed Belts 41x13 - 1740 Li

ConCar Variable Speed Belts 41x13 – 1,740 mm inner length – DIN 7719 / ISO 1604

The ConCar Variable Speed Belts 41x13 with an inner length of 1,740 mm is a variator belt compliant with DIN 7719 and ISO 1604, designed for continuous operation in continuously variable speed drives (CVTs). Unlike a conventional V-belt, which runs on a fixed diameter, a Variable Speed Belts must maintain consistent friction across the entire adjustment range of the pulleys. To achieve this, it is significantly wider than it is tall and has a shallower flank angle, ensuring that the wedge effect remains uniform across the entire radial path and preventing the belt from binding or slipping at the end positions.

This length in the drive

The inner length of 1,740 mm is a long version for the 41x13 profile and is intended for drives with a large center distance, approximately 195 mm with two identical pulleys of 450 mm effective diameter. At 1.191 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 recheck the tension 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 1,740 mm; it is measured at the inner circumference of the belt and is the standard ordering dimension in Germany. The effective length (Ld) of 1,800 mm refers to the neutral axis and is the dimension used in many catalogs and drive calculations. The outer length (La) of 1,822 mm is measured at the back of the belt. With a profile height of 13 mm, the difference between the inner and outer lengths is 82 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): 1,740 mm

• Effective length (Ld): 1,800 mm

• External length (La): 1,822 mm

• Profile: 41x13 according to DIN 7719 / ISO 1604

• Top width: 41 mm

• Height: 13 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: 1.191 kg

• Article number: G441131740

• EAN: 4059213023463

• Manufacturer: ConCar

Structure and materials

The belt consists of a chloroprene blend (CR) with an embedded polyester tensile cord. Chloroprene was deliberately chosen here: it is resistant to oil mist, ozone, UV radiation, and weathering, and retains its elasticity in a temperature range of approximately -30 to +80 degrees Celsius. The polyester cord absorbs the tensile forces and keeps elongation low over the belt's lifespan, which is particularly important in a variator because an elongated belt length directly translates into a shift in the control range.

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 41 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

Before ordering, check the adjustment range of your drive. The belt must be able to be fitted without force, whether the pulleys are fully closed or open. After fitting, tension the belt to the tension specified by the machine manufacturer and check again after the break-in period. If several belts run in parallel in one drive, they must always be replaced as a complete set, as a new belt, in addition to worn ones, bears the entire load.

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 41x13 profile and an inner length of 1,740 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 41x13 / VARIO POWER 41x13

• GATES: Multi-Speed ​​41x13 / Predator V Variable Speed

• CONTITECH: VARIO Speed ​​41x13 / CONTI-V VARISPEED

• MEGADYNE: VARISECT 41x13

• MITSUBOSHI: VARI-SPEED 41x13

• BANDO: Variable Speed ​​41x13

• PIX: Variable Speed ​​41x13

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.