ConCar Variable Speed Belts 23x10 - 813 Li

ConCar Variable Speed Belts 23x10 – 813 mm inner length – DIN 7719 / ISO 1604

This ConCar Variable Speed Belts with a 23x10 profile and an 813 mm inner length, is a toothed variator belt conforming to DIN 7719 and ISO 1604. Variable Speed Belts are the mechanical alternative to frequency converters: they regulate the output speed purely through geometry, without electronics, harmonics, or an additional heat source in the control cabinet. In many woodworking, textile, and agricultural machines, this remains the more robust solution because it operates reliably even in dusty, humid, and vibration-prone environments.

This length in the drive

With an inner length of 813 mm, this belt belongs to the short end of the 23x10 profile. Short belts complete significantly more revolutions at the same belt speed: at 20 m/s, this belt completes approximately 23.3 revolutions per second, each with two complete bending cycles. Therefore, the service life of short belts is almost always limited by the number of bending cycles and not by the tensile load. In such drives, pay particular attention to the smallest effective diameter and ensure that the tension is no higher than necessary.

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 813 mm; it is measured at the inner circumference of the belt and is the standard ordering dimension in Germany. The effective length (Ld) of 858 mm refers to the neutral axis and is the dimension used in many catalogs and drive calculations. The outer length (La) of 876 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): 813 mm

• Effective length (Ld): 858 mm

• External length (La): 876 mm

• Profile: 23x10 according to DIN 7719 / ISO 1604

• Top width: 23 mm

• Height: 10 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: 0.206 kg

• Article number: G423100813

• EAN: 4059213020936

• Manufacturer: ConCar

Structure and materials

The belt consists of a chloroprene rubber core with a longitudinally inserted polyester cord as a tensile member. The flanks are open, meaning they are not covered with fabric. This noticeably increases the coefficient of friction on the pulley and thus improves the transmissible torque, but in return requires clean, unworn pulley flanks. The compound is antistatically conductive according to ISO 9563, which allows the belt to be used in dusty areas and in ATEX-relevant environments.

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 upper width of 23 mm 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 typically found in compact drives: bench drills and small lathes with continuously variable spindle speed, feed drives on band and circular saws, laboratory centrifuges and shakers, dosing and small conveyors in packaging lines, as well as garden equipment and small drives where the installation space does not allow for large pulleys.

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 23x10 profile and an 813 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 23x10 / VARIO POWER 23x10

• GATES: Multi-Speed ​​23x10 / Predator V Variable Speed

• CONTITECH: VARIO Speed ​​23x10 / CONTI-V VARISPEED

• MEGADYNE: VARISECT 23x10

• MITSUBOSHI: VARI-SPEED 23x10

• BANDO: Variable Speed ​​23x10

• PIX: Variable Speed ​​23x10

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.