Conveyor Troughing Idlers Matched to Your Belt Width and Trough Angle
Troughing idlers for belt widths 400-2400 mm in 20, 30 and 45 degree troughs. Q235 tube, 89.1-165.2 mm roll diameter, CEMA B-F. Built to your drawing.
A troughing idler is the carrying-side station: three rolls set at an angle so the belt runs in a trough instead of flat. The side rolls carry the load, the middle roll carries the fines that fall between them, and the trough angle decides how much material the belt can hold without spilling over the edge.
We build troughing idlers against belt width and trough angle rather than against a catalogue part number. 20, 30 and 45 degrees are the standard tooling; 35 degrees and any other angle are built to drawing, with no tooling charge on a first order. If you only know the belt width and the capacity, we can size the rest.
What You Are Actually Getting
| Parameter | Specification |
|---|---|
| Roll diameter | 89.1 / 114.3 / 139.8 / 165.2 mm standard; other diameters cut to drawing |
| Roller length (L) | 145 - 880 mm across the standard belt widths, up to 3400 mm to drawing |
| Trough angle | 20, 30, 45 deg standard; 35 deg and any other angle to drawing |
| Tube | Q235 steel, equivalent to SS400 / S275JR. Wall thickness 3.2 - 3.7 mm light and medium duty, 4 mm where the tender requires it, 5 - 7 mm heavy or high-abrasion duty |
| Shaft | 45# steel, equivalent to DIN C45 / JIS S45C / AISI 1045 |
| Bearing | Deep-groove ball 6204 - 6310. HRB or ZWZ as standard build, SKF or FAG where the specification names them. C3 clearance standard, C4 on clinker, sinter and coke |
| Seal | Grease-retaining inner seal, multi-stage labyrinth, retention cap |
| Life rating | CEMA B / C - 30,000 hours L10; CEMA D / E / F - 60,000 hours. Published at the CEMA basis speed of 500 rpm |
Troughing Idler Dimensions by Belt Width
The full standard range, belt width 400 to 2400 mm. H is the installed height of the set at each trough angle, so you can check it against your existing stringer before ordering.
| Belt width | Roll dia. | L | M | H 20 deg | H 30 deg | H 45 deg | Bolt Z | Weight |
|---|---|---|---|---|---|---|---|---|
| 400 | 89.1 | 145 | 690 | 225 | 235 | 275 | M12 | 5.9 |
| 450 | 89.1 | 165 | 740 | 230 | 245 | 290 | M12 | 6.2 |
| 500 | 89.1 | 180 | 790 | 235 | 250 | 300 | M12 | 6.5 |
| 600 | 89.1 | 210 | 890 | 260 | 280 | 340 | M12 | 8.7 |
| 750 | 114.3 | 265 | 1090 | 320 | 325 | 395 | M12 | 11.4 |
| 900 | 114.3 | 315 | 1240 | 320 | 345 | 430 | M12 | 12.6 |
| 1050 | 139.8 | 370 | 1390 | 385 | 411 | 515 | M16 | 20.6 |
| 1200 | 139.8 | 420 | 1540 | 400 | 435 | 550 | M16 | 22.3 |
| 1400 | 165.2 | 500 | 1790 | 510 | 550 | 690 | M16 | 44.1 |
| 1600 | 165.2 | 580 | 1990 | 540 | 585 | 750 | M16 | 49.9 |
| 1800 | 165.2 | 650 | 2280 | 590 | 645 | 830 | M16 | 63.3 |
| 2000 | 165.2 | 730 | 2480 | 620 | 680 | 885 | M16 | 67.6 |
| 2200 | 165.2 | 800 | 2680 | 665 | 730 | 955 | M20 | 93.5 |
| 2400 | 165.2 | 880 | 2880 | 690 | 760 | 1015 | M20 | 100.8 |
Dimensions in mm, weight in kg per set. L is the roll length, M the set width across the end brackets. Angles outside 20, 30 and 45 degrees are built to drawing.
Three Things That Decide How Long a Troughing Set Lasts
Trough angle against material
A deeper trough holds more material at the same belt width, but it also pinches the belt edge and raises the load on the side rolls. 45 degrees earns its place on high-capacity lines with free-flowing material; on sticky or lumpy material it can bridge and pack. Tell us what the belt carries and we will tell you which angle we would build.
Roller spacing against belt sag
Spacing is set by material weight and belt stiffness, not by habit. Too wide and the belt sags between stations, which costs power and starts the belt walking. Too tight and you are buying idlers you did not need. Our load and spacing calculation is on the site - see the idler load calculator.
Seal stack against dust
Troughing stations sit directly under the load, so they take the dust. The labyrinth plus retention cap is what keeps that dust out of the bearing, and it is the part most often cut on a cheap idler. We do not substitute it.
Where Troughing Idlers Are the Wrong Choice
- Loading points — Directly under the chute the impact energy is too high for a plain troughing roll - use impact rollers with rubber rings at the first two or three stations, then revert to troughing.
- Long horizontal runs — This is the natural application, and where the CEMA life class matters most, because a 30,000 hour roll and a 60,000 hour roll look identical on the day they are installed.
- Steep inclines — Troughing sets hold material on the incline, but above the material's angle of repose the belt itself has to be cleated. See the chevron belt page instead.
Conveyor Troughing Idlers FAQ
What trough angle should I specify?
It follows the material and the capacity. 20 degrees is common on wide belts carrying lumpy or sticky material, 35 and 45 degrees on high-capacity lines with free-flowing material. If your existing conveyor runs a specific angle, match it - the trough angle sets the set height, and the set height has to fit your stringer.
Can you build 35 degree troughs?
Yes. 35 degrees is not in our standard tooling table, so it is built to drawing. There is no tooling charge on a first order, and the lead time is the same as a standard angle once the drawing is approved.
Do you supply the frames as well as the rolls?
Yes - carrying frames, brackets and stringers. Ordering rolls and frames together is the safer route, because roll face length only works if the frame series matches it.
What is the minimum order?
There is no fixed minimum. A trial set is fine, and mixed models in one container are normal for us.
What Else Goes With This
How Orders Run
T/T — 40% deposit with order, 60% balance before shipment. L/C at sight accepted for container orders.
Quoted per order. The schedule depends on the drawing, the quantity and the material — we state a firm date with the quotation instead of a catalogue figure.
15 months from B/L date against manufacturing defects. Claims supported by photos and batch number.
Packing, minimum order and Incoterms are set out in full on the quotation page.
Conveyor Troughing Idlers Built to Your Drawing
Send the belt width, the duty and, if you have one, the drawing. We will specify it, quote within 24 hours, and ship samples in 2–3 days.
Talk to Our Engineers