Conti Synchroflex T5 420

Conti Synchroflex T5 420 – endless metric timing belt for synchronous drives

Conti Synchroflex T5 420 is an endless, cast polyurethane timing belt with 84 teeth, 5 mm tooth pitch and a pitch length of 420 mm. It is intended for synchronous power transmission, where the driving and driven shafts must follow a fixed tooth ratio without the slippage known from friction-based belt drives. The pitch length is the nominal length measurement in the cord line of the belt and is therefore the measurement that must be compared with the existing belt, the machine's spare parts data and the installed timing belt pulleys. This is the standard version in the specified profile. It must not be confused with a possible GEN III version or a double-sided DL belt with the same pitch length.

Fixed specifications

• Pitch length: 420 mm
• Number of teeth: 84
• Tooth profile: T5
• Tooth pitch: 5 mm
• Material: cast polyurethane with steel cord
• Brand: Conti Synchroflex

The technical data below describes the part of the product that does not change when a different belt width is selected. Pitch length, tooth pitch and number of teeth remain identical for all width choices. However, the width affects the available belt cross-section width and the price calculated on the product page. Correct sizing must always take into account torque, speed, number of teeth in mesh, pulley diameters, service factor and any counter-bending.

Why the correct profile is crucial

The T-profile is the classic metric timing belt profile with trapezoidal teeth and is described as a standard profile according to DIN 7721. It is used for general synchronous drives, positioning tasks and solutions with significant bending. The simple and proven geometry of the profile makes it widely used, but it still needs to be matched with a T-disc with the same tooth pitch. AT, HTD and other profiles are not automatically interchangeable.

How the Conti Synchroflex belt is constructed

Conti Synchroflex is manufactured by casting, where the polyurethane is precisely shaped to the tool's tooth geometry around the embedded steel cord tension elements. The casting process provides high pitch accuracy over the entire circumference of the belt and a strong connection between PU and cord. The finished timing belt is endless and therefore has no welded joints. The polyurethane provides a wear-resistant tooth and back surface, while the steel cord takes the longitudinal tensile load.

Standard, GEN III or DL ​​– this version

The standard version is selected when the supplier's article data does not specify GEN III or DL. This is an important product distinction, because different versions can share both profile and length. Therefore, on this product page, it is the standard version that is described. The belt width can be selected, but the basic construction and tooth geometry are not changed.

Which drives is the product compatible with?

Continental cites office machines, household appliances, positioning drives and control drives as examples for this profile family. The examples describe the general area of ​​application of the profile, but do not constitute an approval for any specific installation. The final belt width and pretension must be selected based on the transmitted torque, starting and shock loads, operating time, pulley sizes, speed and the number of teeth in simultaneous engagement. For safety-critical or heavily loaded drives, an actual calculation should be made.

Temperature, media and service

The standard material is specified for ambient temperatures from -30 °C to +80 °C. Applications close to the limits, especially below -10 °C or above +50 °C, may require special sizing. The molded PU belt is maintenance-friendly and does not require lubricant. Regular visual inspection is still relevant: look for ctiming bars, frayed edges, shiny tooth flanks, foreign body impressions and abnormal side contact. Sudden changes in noise or grooveing may indicate misalignment, too low tension or worn pulleys.

How the width variants work

The basic price applies to 6 mm, and the other widths are calculated with the same percentage logic as the existing PU timing belts in the webshop. Integer widths from 6 to 50 mm can be selected on this product page. A width of twice the basic width therefore costs 100% more, while a width of one and a half times the basic width gives approximately 50% extra. This price rule is a webshop calculation; it does not replace a technical dimensioning of the belt's load-bearing capacity.

Timing belt pulleys and transmission ratios

The tooth profile of the timing belt pulleys must correspond to the T5 of the belt, and their pitch must be 5 mm. The transmission ratio is determined by the ratio of the number of teeth of the pulleys, not by the width of the belt. A larger pulley usually reduces the bending load, while a very small pulley gives more bending per revolution. The angle of engagement and the number of teeth in mesh must be sufficient for the current load.

How to avoid unnecessary wear and tear

The timing belt pulleys must be parallel and in the same plane. Even minor misalignments can cause the belt to move towards a flange and cause edge or cord damage. The belt should be installed without being twisted, sharply bent or pressed over a flange with a tool. The center distance is adjusted to achieve the calculated preload. Too high a tension increases the bearing and cord load, while too low a tension can cause tooth jumps at load peaks.

What does belt wear indicate?

Early damage is often caused by conditions surrounding the belt rather than the material itself. Bent shafts, worn tooth grooves, foreign objects and incorrect pretensioning can all shorten the service life. In the event of a belt break, the pulleys should therefore be cleaned and inspected before the new belt is fitted. Also check whether load conditions or start-stop cycles have changed since the original design.

Before ordering a replacement

The product's 84 teeth provide a convenient length check. Multiplying the number of teeth by 5 mm gives a pitch length of 420 mm. If an existing belt has a different number of teeth, it is not the same size, even though it may look almost the same length. Also check that the teeth on the pulleys match the T5; the same pitch number alone is not always sufficient.

Technical questions about the product

How many teeth does the Conti Synchroflex T5 420 have?

The belt has 84 teeth. The number of teeth is calculated by dividing the pitch length of 420 mm by the tooth pitch of 5 mm. The result is 84, and this number can be used as an additional check when identifying an existing belt. A different number of teeth means a different pitch length.

Conti Synchroflex T5 420: what does the steel cord mean for the function of the belt?

The steel cord tension members absorb the longitudinal tensile load and provide high longitudinal stiffness. This helps maintain pitch and position during operation. The cord must not be kinked, exposed or damaged during installation, as local damage can weaken the belt.

Conti Synchroflex T5 420: can the belt be used for precise positioning?

The tooth engagement provides a positive, synchronous transmission without the normal slippage of a friction belt. This makes the profile relevant for positioning tasks, but the achievable accuracy also depends on the quality of the pulleys, shaft play, belt pretension, load and the overall machine design.

Conti Synchroflex T5 420: how best to store a spare timing belt?

Store the belt in a dry, clean place away from direct sunlight, ozone, strong heat or chemical fumes. It should be free from sharp bends and without heavy loads on top. Avoid hanging a small belt over a sharp hook as this can cause local deformation.

Conti Synchroflex T5 420: what happens if the discs are not aligned?

Misalignment can cause the belt to wander towards a flange, causing edge pressure, heat and wear damage. It can also affect tooth engagement and reduce service life. Check both the parallelism of the shafts and the alignment of the pulleys.

Conti Synchroflex T5 420: what should be checked after the first run-in?

Check that the belt runs centrally, that there is no abnormal heat or noise, and that the edges are not constantly rubbing against the flanges. Also look for signs of too low or too high pretension. If the drive requires a re-tension check, the machine manufacturer's procedure must be followed.

Conti Synchroflex T5 420: does this PU timing belt need to be lubricated?

No. The timing belt is designed for lubrication-free operation. Oil or grease should not be added to reduce noise as this may mask an alignment, pretension or worn pulley problem. Instead, keep the tooth mesh clean and check the cause of any abnormal noise.

The most important thing about this size

The product brings together the specified T5 profile and length on one side, so that the appropriate width can be selected without creating a separate item for each cut. The main technical data is 420 mm pitch length and 84 teeth. If in doubt about load or pulley compatibility, the drive should be calculated before ordering the belt.