ConCar Variable Speed Belts 17x5 - 875 Li

ConCar Variable Speed Belts 17x5 – 875 mm inner length – DIN 7719 / ISO 1604

This ConCar Variable Speed Belts with a 17x5 profile and an inner length of 875 mm, 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 875 mm, this belt is one of the longer versions of the 17x5 profile. For two equally sized pulleys with an effective diameter of 180 mm, this corresponds to a center distance of approximately 165 mm. Long belts are less prone to bending stress; at 20 m/s, they rotate only about 22.2 times per second. However, they require more attention to tension: the slack side tends to flutter with large center distances, and the belt's own mass generates additional centrifugal force during operation, which reduces the contact pressure on the pulley.

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 875 mm; it is measured at the inner circumference of the belt and is the standard ordering dimension in Germany. The effective length (Ld) of 899 mm refers to the neutral axis and is the dimension used in many catalogs and drive calculations. The outer length (La) of 907 mm is measured at the back of the belt. With a profile height of 5 mm, the difference between the inner and outer lengths is 32 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): 875 mm

• Effective length (Ld): 899 mm

• External length (La): 907 mm

• Profile: 17x5 according to DIN 7719 / ISO 1604

• Top width: 17 mm

• Height: 5 mm

• Flank angle: 24°

• 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: 0.101 kg

• Article number: G417050875

• EAN: 4059213020387

• 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 24° 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 17 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 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 17x5 profile and an 875 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 17x5 / VARIO POWER 17x5

• GATES: Multi-Speed ​​17x5 / Predator V Variable Speed

• CONTITECH: VARIO Speed ​​17x5 / CONTI-V VARISPEED

• MEGADYNE: VARISECT 17x5

• MITSUBOSHI: VARI-SPEED 17x5

• BANDO: Variable Speed ​​17x5

• PIX: Variable Speed ​​17x5

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.