Conti Synchroflex AT5 GEN III 390

Conti Synchroflex AT5 GEN III 390 – precise PU timing belt for synchronous power transmission

With 78 teeth distributed over a pitch length of 390 mm, the Conti Synchroflex AT5 GEN III 390 is designed for precise transmission of rotation, stroke and position. The belt is cast endlessly in PU and has integrated steel cord tension elements that stabilize the length during normal operation. The nominal tooth pitch is 5 mm and the tooth profile must match the profile of the pulleys precisely. It is not sufficient for another belt to have approximately the same length or width. The GEN III version is the reinforced high-performance construction with red high-performance polyurethane and denser, two-filament steel cord. It should therefore be treated as a separate product series and not as the usual standard version.

Product data and fixed targets

• Pitch length: 390 mm
• Number of teeth: 78
• Tooth profile: AT5 GEN III
• Tooth pitch: 5 mm
• Material: cast polyurethane with steel cord
• Brand: Conti Synchroflex

These specifications can be used as a check against the marking on the old belt or against the machine's spare parts list. The pitch length is not necessarily the same as a measurement across the outside of the belt, and the number of teeth is therefore often the safest additional check. If in doubt, both the belt and timing belt pulleys should be examined before ordering a replacement.

Profile, tooth pitch and engagement

The AT profile has been further developed from the classic T profile. The larger tooth volume provides a higher tooth shear strength, and the profile is designed for a favorable tooth engagement with reduced engagement shocks. This makes the AT series suitable when a drive must be compact and at the same time transmit motion precisely. Continental states that the AT profile can perform up to 50% more than a corresponding T profile, but the actual capacity always depends on width, discs, speed and load profile.

Cast polyurethane and steel cord

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.

The construction behind this variant

GEN III is the reinforced high-performance version of the Conti Synchroflex series. The construction uses red high-performance polyurethane, more densely packed steel cord tension elements and a two-filament construction with balanced S and Z cords. Continental states up to 25% higher power transmission than the corresponding AT or ATP standard series. GEN III can use the standard profile timing belt pulleys, but the belt still needs to be dimensioned for the specific drive.

The belt width is selected on the product page

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.

Typical applications and sizing

Continental cites machine tools, pu , textile machines and positioning and conveying systems 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.

Compare with the existing belt

It is not enough to compare the total circumference of a belt. The correct replacement must have the same pitch, tooth profile and number of teeth as the existing drive. The width must match the pulleys and the required capacity, and a DL or GEN III version must be identified separately. If in doubt, pictures of the marking, tooth profile and pulleys can be used as a supplement, but a documented spare part designation is best.

Disc geometry and tooth engagement

A belt with the correct length can still function poorly if the pulleys have the wrong profile, are worn or are misaligned. Therefore, check the tooth grooves, flanges, shaft alignment and the number of teeth on the pulleys. For AT5 GEN III, the nominal tooth pitch is 5 mm. The fixed tooth mesh makes the gear ratio reproducible, but only when the belt has sufficient wrap and does not run with constant side pressure.

How to avoid unnecessary wear and tear

When installing, the cord pullers must be protected against kinks and local pressure damage. The belt must not be pinched with pliers or a screwdriver, and it should not be folded sharply. Check that the pulleys have the same pitch and profile as the belt and that they are not worn out. A stable drive is achieved through the right combination of alignment, wrapping and calculated pretension.

Checking teeth, back and edges

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.

Operating environment and maintenance

Continental specifies a temperature range of up to +100 °C for the GEN III series. When operating close to the temperature limits, the drive must still be dimensioned according to the specific load and environmental conditions. The cast 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 can be signs of misalignment, too low tension or worn pulleys.

Frequently Asked Questions

Conti Synchroflex AT5 GEN III 390: what temperature can the belt work at?

The GEN III series is rated for temperatures up to +100°C. When operating close to the limit, load, cooling and environment must be assessed separately.

Conti Synchroflex AT5 GEN III 390: can the width be measured with a regular caliper?

Yes, the belt width can usually be measured directly on the flat back or between clean, undamaged edges. However, the width is only one part of the identification. The profile, pitch length, number of teeth and any DL or GEN III version must also be correct.

Conti Synchroflex AT5 GEN III 390: can the belt be shortened or assembled to a different length?

No. This is a cast endless timing belt with a fixed pitch length. It can be cut to width within the available options, but the circumference and number of teeth cannot be changed. If the length needs to be changed, a different cast belt size is required.

Conti Synchroflex AT5 GEN III 390: why is GEN III not merged with the standard version?

GEN III has a different material construction and capacity data than the standard belt. The higher cord density, two-filament construction and high-performance polyurethane make it a separate product line, even though the pitch length and tooth profile may be identical.

Conti Synchroflex AT5 GEN III 390: 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 AT5 GEN III 390: can this belt be used at high rpm?

The Conti Synchroflex series is designed for precise and fast synchronous drives, but the permissible speed depends on the profile, pulley diameter, belt width, load and peripheral speed. A high speed must therefore not be approved based on the product name alone; the drive must be calculated.

Is the Conti Synchroflex AT5 GEN III 390 welded?

No. The Conti Synchroflex series is manufactured as cast, endless timing belts. The belt therefore does not have a welded joint around the circumference. The cast process provides a uniform tooth pitch around the entire belt and a strong bond between the polyurethane and the cast steel cord tension elements.

Conti Synchroflex AT5 GEN III 390: what is the difference between tooth pitch and pitch length?

The tooth pitch is the distance from one tooth to the next and is 5 mm for this profile. The pitch length is the entire nominal circumference in the cord line and is 390 mm. When the pitch length is divided by the tooth pitch, the belt has 78 teeth.

Brief summary

The product brings together the specified AT5 GEN III 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 390 mm pitch length and 78 teeth. In case of doubt about load or pulley compatibility, the drive should be calculated before ordering the belt.