PU round belts and PU V-belts: where each fits

"PU belt" covers more than one product. This post compares two polyurethane profiles that Probe lists on its PU V & round belts page: round belts and V-belts. It sets out what each is, where each fits, what manufacturer datasheets say about round belts, and what to confirm before you order.

A note on sources. Probe's page gives few numbers. It lists no diameters, section codes, temperature range or tensile data. The ranges in this post come from manufacturer datasheets for PU round belts in general. They are typical values, not Probe specifications.

What Probe's page lists

Both profiles share one specification set:

• extruded from virgin thermoplastic polyurethane (TPU);
• 85/90 ShA hardness as standard, with custom colours and other hardness levels on request;
• three reinforcement options: not reinforced, polyester reinforced and aramid reinforced;
• welding on site.

Probe describes each profile as follows:

• Polyurethane V-Belts. A trapezoidal cross-section for high wedging grip. Weldable on site, with no drive disassembly required. High resistance to oils, chemicals and industrial pollutants. Typical use: general light power transmission drives in packaging, automation and industrial machinery, where chemical resistance and on-site joining speed matter.
• Polyurethane Round Belts. A circular profile that fits V-groove and round-groove pulleys. It runs over twist, curve and cross-axis drive paths, with a smooth, non-marking surface for product handling. Typical use: multi-directional conveyor systems, sorting lines, roller drives and product-transfer applications.

Which kind of PU V-belt?

"PU V-belt" covers at least three families, and they are not interchangeable:

1. Open-ended solid PU V-belts, cut from a roll and welded endless. Suppliers list them in classical profile names (Y, M, Z, A, B, C and D, from 6 × 4 mm to 32 × 20 mm, width by height) and position them mainly for conveying: tiles, glass, boards, cartons and packaging.
2. Modular link V-belts, made of PU and polyester fabric links, whose length is set by adding or removing links. One manufacturer states that they run on standard V-belt pulleys.
3. 60-degree cast PU drive belts, a different class of power-transmission belt.

Probe's page describes an extruded, trapezoidal belt that is welded on site. That points to the first family, the open-ended welded belt. The page does not name profile codes or sizes, so ask which profiles are available. Probe has a separate link belts page, which describes link belts as an upgrade for conventional rubber V-belts. Poly-V (ribbed) belts and rubber classical or narrow V-belts are separate products again. Probe covers poly-V on its V belts and poly ribbed belts page.

Supplier literature positions open-ended PU V-belts mainly for conveying, while Probe's page lists light power transmission drives. Ask for an application review rather than assuming a drive duty.

Round belts: what the datasheets say

These ranges come from manufacturer datasheets, not from Probe's page:

• Diameter. Stocked solid round belts run from about 2 mm to 15 mm. Some catalogues list up to 20 mm.
• Hardness. The range is about 65 to 98 Shore A, and common working grades sit around 85 to 92 Shore A. Harder grades carry more load but need a larger minimum pulley. Softer grades grip and flex better. Probe's standard 85/90 ShA sits inside the common working band.
• Surface. Round belts come smooth or rough. Manufacturers promote rough surfaces for wet or greasy products and for curves. Treat that as a vendor claim.
• Pre-stretch. The installation stretch is about 2% to 8%, depending on hardness and diameter. Softer, thinner belts sit toward 8%. Harder, thicker belts sit at 2% to 4%. Follow the datasheet for the exact belt.
• Temperature. Standard PU round belt datasheets give roughly -20 °C to +60 °C. Harder grades from one manufacturer extend to about +80 °C or +90 °C. One 87 Shore A TPU datasheet lists -25 °C to +50 °C continuous.
• Minimum pulley. One manufacturer gives 10 times the belt diameter for its 87 Shore A belt. Other makers set it by grade.
• Chemistry. PU resists oils, greases and many non-aggressive chemicals. Hot water and steam, strong acids and alkalis, and aromatic or ketone solvents damage it.

Guidance on the best pulley groove for a round belt is not uniform across suppliers. Take the groove dimensions from the datasheet for the belt you specify.

Where each fits

Round belts fit where the drive path twists, curves or crosses axes, where rollers need driving, and where a smooth, non-marking surface matters. Probe's industries list for the page includes food, paper and printing, logistics, and raw materials and construction.

V-belts fit where wedge grip on a trapezoidal groove matters. Probe cites packaging, automation and industrial machinery, with chemical resistance and fast on-site joining as the reasons to choose PU.

Load sets the limit for both. Probe's FAQ says its PU belts can be custom-engineered with polyester or aramid tensile cords for highly demanding power transmission, and that the reinforcement prevents elongation. Probe's page lists no maximum tension or load figures, so those need confirming for your drive.

Rubber V-belts are the baseline. Probe's page says PU brings flexibility and chemical resistance that standard rubber cannot match. It publishes no power comparison with rubber V-belts, and no source we reviewed gave one with numbers. Treat any PU-versus-rubber power claim with caution and ask for the datasheet.

For belt-driven rollers inside a conveyor, see belt, roller or slat conveyor: choosing the right system. For logistics lines, see Probe's logistics industry page.

Joining on site

Suppliers cut PU round belts and open-ended PU V-belts from a roll and weld them endless on site. Probe's page says its technical team can perform rapid on-site jointing at your facility, to keep downtime minimal. The V-belt needs no drive disassembly.

Environment and compliance

Check the datasheet temperature grade for your operating conditions. Datasheets give windows, and this post makes no claim about performance in UAE heat. Keep hot water and steam in mind, since both degrade PU.

Food-contact compliance is belt-specific. It is not a property of PU in general. For any food or beverage application, ask for the declaration of conformity for the specific belt.

What to tell us

Probe's page says its engineers select the profile, hardness rating and tensile reinforcement for your load and duty cycle. To get that selection, bring:

• the profile you expect, round or V, and the diameter or section if you know it;
• the hardness and reinforcement you want: none, polyester or aramid;
• the drive layout: twists, curves, cross-axis paths or roller drives;
• pulley diameters and groove type;
• the load or drive duty;
• the temperature, and any oil, chemical or hot-water exposure;
• the colour you need, and whether the belt must be joined on site.

To request a quote, use Get a Custom Quote on the PU V & round belts page. Probe is based in National Industries Park, UAE.

Sources

• Round-belt ranges come from manufacturer datasheets and brochures, which are not named here.
• Probe figures come from the PU V & round belts page.