Quick answer: Veybelt makes four radius (side-flexing) modular belt series. If the turn is the constraint, take series 916: inner radius 1.7 x belt width, tightest in the range, with 60% open area for drainage and airflow. If pull is the constraint, take series 7100 for the strongest PP rating (24,200 N/m) at a still-tight 2.3 x turn, or series 2400 for the top POM figure (31,800 N/m) on a 25.4 mm pitch. Series 300 is the rugged coarse option: 46 mm pitch, 41.5% open grid. All four run S-curves and 90/180-degree layouts on one drive.
What is a radius modular belt?
A standard modular belt only runs straight. A radius belt, also called a side-flexing or turn belt, has modules and hinge rods shaped so one edge can compress while the other fans out. The belt follows a horizontal curve and the sprockets keep driving it positively the whole way: no slip, no separate turn unit.
Two numbers decide every radius belt selection:
- Inner turning radius. The tightest curve the belt can follow, measured from the curve center to the inside belt edge and quoted as a multiple of belt width. A 500 mm wide belt rated 2.5 x needs at least 1,250 mm of inside radius. Lower multiplier, tighter turn, smaller footprint.
- Edge collapse in the turn. Entering a curve, the inside edge shortens its pitch while the outside edge stays extended. How far the geometry lets the inside edge collapse is what fixes the minimum radius. It also means the inside edge takes a disproportionate share of the tension in a curve, so check belt pull against belt strength harder than you would on a straight run.
One belt covering straights, curves and inclines removes the transfers between conveyors. Fewer transfers, fewer tipped bottles, fewer jam points, fewer drives to maintain. Spiral conveyors are the same trick taken vertical: the belt wraps a drum in a helix to gain elevation in a small footprint, which is how cooling, proofing and freezing towers work.
Series comparison: 300 vs 916 vs 2400 vs 7100
| Series | Pitch | Belt strength | Inner turn radius | Open area | Thickness | Material | Best for |
|---|---|---|---|---|---|---|---|
| 300 | 46 mm | 18,200 N/m (PP) | 2.5 x belt width | 41.5% | 14.5 mm | PP | General curved conveying on a coarse, easy-to-clean open grid; washdown and drainage sections |
| 916 | 25.4 mm | 14,200 N/m (PP) / 14,700 N/m (POM) | 1.7 x belt width | 60% | 13 mm | PP / POM | The tightest turns in the range, spiral layouts, and cooling or drying where air must get through the belt |
| 2400 | 25.4 mm | 17,000 N/m (PP) / 31,800 N/m (POM) | 2.5 x belt width | 44.2% | 13 mm | PP / POM | Heavily loaded curves where POM strength is needed on a fine pitch |
| 7100 | 25.4 mm | 24,200 N/m (PP) / 30,900 N/m (POM) | 2.3 x belt width | 44.2% | 12.8 mm | PP / POM | Long curved runs that need high strength in PP, or strength plus a tighter turn than the 2400 gives |
Start from the turn. If floor space forces a tight curve, the 916 is the only 1.7 x belt we make; the decision is made for you. If the layout tolerates 2.3–2.5 x, decide on load instead: 7100 for the strongest PP, 2400 for the strongest POM, 300 when a heavier 46 mm module suits abrasive or rough-handling duty.
Series 300: 46 mm pitch radius belt
The 300 series radius belt is the coarse-pitch option: 46 mm pitch, 14.5 mm thick, PP only, 18,200 N/m with a 41.5% open grid. The big module takes knocks and hoses out easily, which is worth more than a fine carrying surface on a lot of curved washdown lines. Inner turning radius is 2.5 x belt width. Standard colors are white and grey. Drive is by 300 series sprockets (12 teeth, POM).
Series 916: large radius belt for the tightest turns
The 916 series radius belt turns at 1.7 x belt width on a fine 25.4 mm pitch; nothing else in our range turns tighter. Its 60% open area is also the highest of the four, so it is the default for cooling, drying and proofing sections and for spirals, where air has to pass through the belt or the tower does nothing. PP (14,200 N/m) or POM (14,700 N/m), 13 mm thick, widths built as multiples of 152.4 mm. Pair it with 916 series sprockets (machined POM).
Series 2400: high-strength POM radius belt
The 2400 series radius belt shares the 916's 25.4 mm pitch and 13 mm thickness but trades turn tightness for pull: 17,000 N/m in PP, 31,800 N/m in POM, the highest figure in the radius range. Inner radius is 2.5 x belt width, open area 44.2%. This is the belt for heavily loaded curves, long runs with several turns, and anywhere POM wear resistance is a requirement rather than a preference. Driven by 2400 series sprockets (16 teeth, POM).
Series 7100: strong PP belt with a tighter turn
The 7100 series radius belt sits between the 916 and 2400: 2.3 x inner radius, 25.4 mm pitch, 12.8 mm thick, 44.2% open. Its 24,200 N/m PP rating is the best PP figure of the four, and POM lifts it to 30,900 N/m. Spec it when the layout needs real load capacity and a tighter curve than the 2.5 x belts allow, or when you want the strength without paying for POM. Driven by 7100 series sprockets (multiple teeth options, POM).
Sprockets: one matched set per series
Radius belts are still positively driven, and each series has its own dedicated sprocket set: 300 (12 teeth), 916 (machined), 2400 (16 teeth) and 7100 (multiple options). All are POM (acetal) for dimensional stability and wear life, with square, round or bushing-insert bores. They do not interchange between series, so order the set matched to your belt. On the shaft, key only the center sprocket and let the others slide; the belt changes width with temperature and needs that freedom.
How to spec a radius conveyor
A curved conveyor takes a few more data points than a straight one. With the list below in hand we come back with a complete bill of materials:
- Belt width and total conveyor length (center-to-center)
- Inside turn radius of each curve, or the available floor envelope so we can check it against the series turn rating
- Conveyor layout and number of turns: a rough sketch with straight lengths, curve angles (90/180 degrees) and their sequence is enough. Belt pull climbs with every curve, and the layout is what decides whether PP holds or the job needs POM
- Product type, weight per unit and line speed
- Ambient and washdown temperature range
- Drive shaft size, so we match square, round or bushing-insert sprocket bores
- For spirals: drum diameter, number of tiers and elevation gain, described as fully as you can
Request a radius belt quote. Belt and matched sprockets ship as one order, straight from the manufacturing base, custom widths built to order.
