ConCar Variable Speed Belts 52x16 - 1525 Li

ConCar Variable Speed Belts 52x16 – 1,525 mm inner length – DIN 7719 / ISO 1604

The ConCar Variable Speed Belts 52x16 x 1.525 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 1,525 mm is a standard length in the mid-range for the 52x16 profile. For reference: With two pulleys of the same size and an effective diameter of 400 mm, the corresponding center distance is approximately 170 mm. At a belt speed of 20 m/s, the belt rotates around 12.5 times per second. This combination of moderate bending frequency and sufficient wrap is the reason why most series production drives operate within this length range.

For design purposes and comparison with an existing belt, the three length specifications are important because manufacturers use different reference dimensions. The inner length (Li) is 1,525 mm; it is measured at the inner circumference of the belt and is the standard ordering dimension in Germany. The effective length (Ld) of 1,600 mm refers to the neutral axis and is the dimension used in many catalogs and drive calculations. The outer length (La) of 1,626 mm is measured at the back of the belt. With a profile height of 16 mm, the difference between the inner and outer lengths is 101 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): 1,525 mm

• Effective length (Ld): 1,600 mm

• External length (La): 1,626 mm

• Profile: 52x16 according to DIN 7719 / ISO 1604

• Top width: 52 mm

• Height: 16 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: 1.449 kg

• Article number: G452161525

• EAN: 4059213024200

• 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, ensuring smooth belt operation across the entire pulley adjustment range and preventing binding at the end positions. Simultaneously, the large 52 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

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.

Before you classify a belt as worn, it's worth taking a look at the pulley. A worn groove allows the belt to sink deeper, causing it to sit on the bottom of the groove and lose contact with the belt flanks. This manifests as a sudden loss of power, even with a seemingly new belt. This can be checked in a minute using a groove feeler gauge.

Similar names for other brands

Variable Speed Belts are standardized according to DIN 7719 and ISO 1604. A belt with a 52x16 profile and an inner length of 1,525 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 52x16 / VARIO POWER 52x16

• GATES: Multi-Speed ​​52x16 / Predator V Variable Speed

• CONTITECH: VARIO Speed ​​52x16 / CONTI-V VARISPEED

• MEGADYNE: VARISECT 52x16

• MITSUBOSHI: VARI-SPEED 52x16

• BANDO: Variable Speed ​​52x16

• PIX: Variable Speed ​​52x16

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.