Flexible Belting for Drive & Conveyor Systems

Different round belts can share the same diameter while behaving very differently in service. Optibelt polyurethane round section belts include solid, tension-cord & hollow constructions for different drive & conveying requirements.

The quickest way to narrow the choice is by construction:

► RR – solid polyurethane round belt for general compatible drive & conveying requirements
► RR PLUS – polyurethane round belt with a tension cord where reduced elongation is important
► HRR – hollow polyurethane round belt particularly suited to lightweight drives, conveyors & smaller pulley diameters

Once the belt family is identified, confirm diameter, required length, pulley arrangement & joining method.

For other industrial belting, explore Flat Belts & Round Belts. Wider drive requirements can be sourced through Power Transmission.

RR Provides a Solid Polyurethane Round Belt

Optibelt RR is an open-ended round belt manufactured from thermoplastic polyurethane.

Its solid construction provides a straightforward solution for compatible machinery using round-section belts for motion transmission or conveying.

RR can be welded into an endless belt at the required length. This can be particularly practical where open-ended material is easier to install through the existing machine layout before the ends are joined.

When identifying RR, record:

► RR product family
► Belt diameter
► Required finished length
► Relevant PU specification
► Colour where applicable
► Existing product reference
► Pulley dimensions

Diameter alone is not enough to identify the belt. A solid RR, tension-cord RR PLUS & hollow HRR may require different selection or joining considerations even where nominal dimensions appear similar.

RR PLUS Reduces Elongation With a Tension Cord

Optibelt RR PLUS combines a polyurethane round-belt body with an internal tension cord.

The key difference is reduced elongation.

Optibelt identifies round belts with tension members as particularly useful for longer transport distances, where belt stretch can become more significant.

RR PLUS is therefore worth considering where the machine requires:

► Polyurethane round-section belting
► Reduced elongation
► Longer conveying distances
► Internal tension-member construction
► An endless joined belt

RR PLUS should still be selected against the requirements of the machine rather than substituted automatically for RR.

Pulley geometry, dimensions, belt length & the joining procedure all need to suit the product being fitted.

Where the behaviour of a transmission needs further investigation, Vibration & Condition Monitoring Tools can support broader machinery condition checks.

HRR Uses Hollow Construction for Greater Flexibility

Optibelt HRR is a hollow polyurethane round belt.

Optibelt particularly recommends HRR for lightweight drive & conveyor systems, including arrangements using smaller pulley diameters. The thick-walled hollow construction gives it a different operating character from solid RR & tension-cord RR PLUS.

Published HRR configurations include:

► 75 Shore A red/smooth – 4.8, 6.3, 8 & 9.5 mm
► 85 Shore A green/rough – 4.8 & 6.3 mm

Colour is therefore not the only distinction between HRR variants. Diameter, Shore hardness & surface finish form part of the specification.

When replacing HRR, retain the complete identification wherever possible rather than ordering from diameter alone.

Match Diameter to the Existing Pulley Arrangement

Round-belt diameter needs to work with the pulley system already fitted to the machine.

A belt that appears approximately the right size is not necessarily the right product.

Check:

► RR, RR PLUS or HRR construction
► Existing belt diameter
► Pulley diameter
► Pulley-groove geometry
► Required finished length
► Centre distance where relevant
► Operating load
► Required pre-tension

This is particularly important with HRR because Optibelt identifies suitability for smaller pulley diameters as one of the advantages of its hollow construction.

Where pulley components also require attention, Pulleys, Blocks & Sheaves provides related power-transmission products.

The goal is to reproduce the belt specification required by the machinery rather than selecting solely by visual size.

Open-Ended Round Belts Can Be Welded Into Endless Belts

Polyurethane round belting can be supplied as open-ended material & joined to produce the required endless length.

The process generally involves:

► Determining the required finished length
► Cutting the belt accurately
► Preparing the joining surfaces
► Positioning the ends in the appropriate clamp
► Completing the specified welding process
► Allowing the joint to set correctly
► Finishing the seam where required

Optibelt provides dedicated welding, clamping, cutting & finishing equipment for compatible polyurethane belts.

Correct tooling depends on the particular belt. A joining method suitable for one round-belt construction should not automatically be assumed suitable for another.

For wider transmission servicing requirements, Drive Accessories & Maintenance provides related drive components.

HRR Is Normally Welded but Can Also Use Connecting Nipples

Compatible HRR hollow round belts have two joining possibilities.

Welding is the normal joining method recommended by Optibelt.

Because HRR is hollow, Optibelt also provides special brass connecting nipples that can be inserted into compatible belts.

Nipple joining is particularly useful for rapid on-site connections. Optibelt also identifies it for suitable drives or conveyors operating with low loads & low speeds.

The distinction is important:

► Welding is the normal HRR joining approach
► Brass nipples are specifically for compatible HRR hollow belts
► Nipple connections are not universal connectors for polyurethane round belts
► Solid RR & RR PLUS require the joining procedure appropriate to their construction

When using an HRR nipple, confirm the belt diameter & corresponding connector before making the joint.

The Joining Tools Need to Match the Belt

Accurate belt joining depends on more than the welding tool itself.

Depending on the belt & joining process, the setup may require:

► Welding equipment
► Guide clamps or clamping jaws
► Cutting shears
► Edge-finishing tools
► HRR connecting nipples where applicable
► Suitable insertion tools for nipple connections

Keeping the correct tooling associated with the belt specification can simplify repeat maintenance, particularly where several machines use different round-belt diameters or constructions.

For related belt-drive hardware, Belt Tensioners & Idlers provides another useful path when supporting transmission components also need inspection or replacement.

Spring Jobsite Prep Getting Your Gear Ready provides broader guidance around identifying equipment requirements before demanding operating periods.

Check the Belt Path Before Installation

Before fitting a new round belt, inspect the components it will run against.

Look for:

► Damaged or worn pulley surfaces
► Incorrect groove condition
► Alignment problems
► Seized or rough-running rollers
► Bearing issues
► Contamination or abnormal heat

Unusual wear on the removed belt can provide useful evidence that something elsewhere in the machine needs attention.

Where alignment requires verification, Alignment Tools (Laser, Dial, Manual) provides equipment for broader drive setup checks.

Quarry Crews Crusher Maintenance also provides practical context around checking connected machinery components rather than treating the failed part in isolation.

Record the Full Round-Belt Specification

“6 mm round belt” is rarely the best maintenance record.

Where possible, record:

► RR, RR PLUS or HRR
► Diameter
► Required finished length
► Colour where applicable
► Surface finish where applicable
► Shore hardness where applicable
► Joining method
► Machine or asset reference

For HRR, noting red/smooth 75 Shore A or green/rough 85 Shore A preserves information that diameter alone does not capture.

A photograph of the original marking or packaging can provide another useful reference for repeat purchasing.

Winter-Proofing Your Tools: Maintenance Tips for the Cold Months provides further maintenance guidance for equipment exposed to changing operating conditions.