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Chevron Cleated Conveyor Belts: Profile Selection for Inclined Haulage

2026-09-29

Inclined haulage is where belt selection stops being a catalogue exercise. A flat belt that behaved perfectly on a 600 m horizontal run starts to slip, spill and polish its own cover the moment the same tonnage has to climb 20 degrees. The usual reaction on site is to buy a bigger motor. That rarely fixes it.

What fixes it is a different top surface, one joined to the carcass in a different way, running over different pulleys. Chevron profiles — the raised V, U or multi-V ribs moulded onto the carrying cover — are the standard answer for slopes that a smooth belt cannot hold. Choosing the profile is the difference between a ribbed belt that runs four years and one whose ribs peel off in eleven months.

Below we take that choice apart: which profile family fits which angle and which material, how rib height and pitch interact, what the base belt has to survive underneath the ribs, and the places where cleated belts quietly fail on real installations.

Send us your incline, angle and material — we will size the profile and quote the belt

01Why a Smooth Belt Runs Out of Grip Above About 18 Degrees

A smooth belt does not really carry material up a slope. It carries material on top of a surface, and the only thing holding the load in place is friction between the bottom of the bed and the moving cover, plus whatever inter-particle locking the material can generate by itself. Once the slope exceeds the angle at which that combined resistance gives way, the top of the bed starts moving backwards relative to the belt. Nobody notices at first, because the belt still moves forward and the tonnage still arrives.

On a 240 t/h crushed limestone incline at 21.5 degrees we replaced a smooth three-ply EP belt with a ribbed belt carrying 15 mm ribs at the same 1.6 m/s belt speed. Back-spillage at the loading skirt stopped inside the first week. The number that surprised the millwrights was the ammeter reading — start-up current rose about 9%, because for the first time the full pocket load was actually reaching the head pulley instead of being recycled downhill.

Ribs do not increase friction. They are a mechanical stop.

Every rib presents a face roughly perpendicular to the direction of travel, so the material no longer has to hold itself on a slope; it is leaning on something. That is why a modest 10 mm rib can transform a 22 degree installation while doubling the cover thickness would barely change anything. It is also why ribbed belts fail differently from flat belts when they do fail — the failure moves from the cover to the bond line under the rib, which is a subject we return to later.

The practical limit for a smooth belt is usually somewhere between 14 and 20 degrees, and it depends far more on the material than on the belt. Hard, sharp, angular material interlocks and will hold at the top of that range. Rounded, free-flowing material with a low internal friction angle gives up early, and wet fines with clay content can slide at 12 degrees while looking perfectly dry on the surface. That is why the same incline specification cannot be reused between two plants that handle visually similar stone.

The table below is the version of that reasoning we use when a customer sends an incline angle and a material name and nothing else. It is a starting point, not a substitute for a test, but it separates the installations that need a light ribbed belt from those that need a deep one, and it usually removes the temptation to specify a heavy profile for a job a light one would do better.

Material family	Static angle of repose (deg)	Practical limit, smooth belt (deg)	Practical limit, ribbed 15–25 mm (deg)	What the ribs actually change
Dry rounded sand and gravel, 0–20 mm	32–35	14–16, because grains roll as a bed rather than interlock	26–30 with a moderate pitch around 400–500 mm	Each rib resets the rolling layer, so grains never build the downhill velocity they need to stream past the next rib
Crushed limestone or granite, 0–40 mm	35–40	18–20 on a new cover, dropping as the cover polishes	28–34, and this is where rib geometry matters most	Sharp faces already interlock, so the rib mostly keeps the upper 50–80 mm of the bed from sliding back over the rest
Sized coal, 0–50 mm, surface dry	35–38	18–20 with a clean cover and steady feed	27–32 depending on how much fines the load carries	The rib stops the sliding layer, but dust sitting in the pockets between ribs is the reason coal lines need a brush cleaner rather than a scraper
Wet coal or clay-bearing fines	45 and above, but the number is misleading	12–16, and unpredictable from day to day	22–28, and the low end is the honest answer	Sticky fines shear internally instead of sliding on the cover, so the rib holds the mass while the wet layer above it still creeps
Grain, pellets and other free-flowing bulk	25–30	12–15	22–27 with shallow ribs and tight pitch	Low internal friction means the whole bed flows, so shallow ribs at a short pitch beat deep ribs at a long pitch every time

Anything past roughly 35 degrees stops being a profile question. A ribbed single-belt incline cannot hold a loose bed much beyond that, and the answer becomes a wholly different construction with cross-rigid carcass and moulded sidewalls, which is a separate family of product and is covered on our sidewall conveyor belt page rather than here.

02Profile Geometry: What Rib Height, Pitch and Chevron Angle Really Control

Buyers tend to describe a profile by one number, usually the rib height, and order on that basis. That is roughly equivalent to specifying a gearbox by its housing diameter. A ribbed belt is defined by at least six dimensions that interact, and two belts with the same 20 mm rib can behave completely differently on the same incline depending on the pitch and the arm angle moulded around them.

Start with clear rib height, measured from the top of the cover to the top of the rib. This is the physical obstacle the material has to climb over, and it is also the depth of the pocket that will carry the load. For our own estimates we want the clear height to be at least 1.5 times the 95th percentile lump size in the stream. Go below that and the larger pieces bridge across the pocket, sit on top of the rib array, and roll back down the slope; the rib is still there, the installation simply does not benefit from it. Go far above it and you have wasted pocket volume, added mass, and made the pulley problem worse, because every millimetre of rib height increases the minimum pulley diameter the belt can be trained around.

Pitch is the distance between rib centres along the belt, and it decides how often the bed gets reset. Long pitch gives more pocket volume per metre and better cleaning access; short pitch resets the bed more frequently and holds light free-flowing material more reliably. The trade is not symmetric. Pitch that is too long lets material accelerate between ribs, so each rib face receives a dynamic impact rather than a static load, and after a few hundred thousand cycles the bond line under that face starts to separate. Pitch that is too short produces pockets the feeder cannot fill, which wastes belt width, increases the number of ribs carrying load, and can make cleaning almost impossible because scrapers and brushes cannot reach into a shallow, closely spaced array.

The chevron arm angle is the third variable and the one most often copied from whatever was on the shelf. A more pronounced V — arms at roughly 45 degrees to the edge — centres the load toward the middle of the belt and works well where the feed is not perfectly aligned. Flatter arms, closer to 70 degrees to the edge, look almost transverse and deliver more capacity per metre of belt for the same rib height. Either will work on a straight incline with a good chute. Where the belt runs slightly off-centre, the sharper V is the more forgiving of the two.

Here is how those dimensions move together in practice.

Dimensional parameter	What it actually controls	Usual range on incline duty	What goes wrong when it is mis-specified
Clear rib height above the cover	Pocket depth and the height of the mechanical stop; also sets the minimum pulley diameter the belt can pass	10–15 mm for 18–25 deg, 15–25 mm for 25–32 deg, 25–35 mm past 32 deg	Too low and oversize lumps roll over the rib; too high and rib roots crack because the terminal pulley is smaller than the profile needs
Longitudinal pitch between ribs	How frequently the sliding bed is interrupted, and the pocket volume available per metre of belt	400–500 mm for dry coarse stone, 300–400 mm for grain and pellets, 500–650 mm only for deep pockets with dividers	Long pitch lets material build speed between ribs and hammers the rib face; short pitch starves the pockets and jams brush cleaners
Chevron arm angle to the belt edge	How strongly the load is centred, and how much capacity each rib adds for a given height	45–60 deg where feed alignment is poor, 60–70 deg where the chute loads the belt squarely	Nearly transverse arms on an off-centre feed let the bed drift and load one edge of the belt, which then tracks badly on the return
Rib base width and taper ratio	Shear distribution at the bond line between rib and cover	Base typically 1.5–2 times the top width, working out at 25–40 mm of base for a 20 mm rib	Narrow base concentrates peel stress into a strip, and rib stripping begins at the root as a hairline split that opens with each pulley pass
Flat edge margin each side	Sealing under skirt rubber, splice trimming, edge wear allowance and contact with guiding rollers	50–100 mm, wider on belts over 1,200 mm with heavy edge loads	Profiles moulded too close to the edge leave nothing to trim at the splice and expose the rib root to edge wear and water ingress

Chevron cleated conveyor belt with moulded V ribs on an inclined belt surface

03Matching the Profile to the Incline and to the Material

Profile selection is a two-step decision, and the steps have to be taken in the right order. The incline angle sets the family — shallow rib, deep rib, or rib plus transverse divider. The material then sets the detail: how tall the rib needs to be to clear the largest lumps, how far apart the ribs need to be to let the bed settle, and whether the cover underneath them can survive the abrasion and the heat.

Because we sit on the supply side of that decision, we see the same error from both directions. A buyer who starts from a stocked conveyor belt manufacturer list tends to pick a profile that exists and then adjust the design around it, which works only while the incline is mild. A buyer who specifies the duty first and shops second gets the better outcome, because the profile is then the conclusion rather than the starting point. Our own preference is to be handed four numbers before anything is quoted — angle, bulk density, 95th percentile lump size, and the wettest condition the stream ever reaches.

Note what an inclined industrial conveyor belt carries underneath the ribs. On a flat run, the carrying cover only sees sliding abrasion and occasional impact. On an incline it also sees the whole weight of the bed leaning on the ribs, transmitted through the bond line into the cover and then into the carcass, plus whatever dynamic load the material imposes when it accelerates between ribs and hits the next face. That is why the base under a ribbed belt is usually a heavier rubber conveyor belt with an abrasion-grade cover rather than the fabric-grade construction that would be adequate on the level.

Angles hand you the family. A useful way to hold the whole range in your head is that every additional six degrees of incline roughly doubles the demands placed on the rib, because the downhill component of the load grows faster than the friction available to resist it. The result is that profiles do not scale linearly.

Incline band	Profile family to use	Rib height	Typical pitch	Why this band behaves the way it does
0 to 16 deg	No profile needed, or a shallow anti-roll profile if the belt is marginal	6 to 10 mm where a profile is used at all	500 to 650 mm, wide enough for easy cleaning	A smooth belt is normally within its friction limit here; a shallow profile is worth considering only where the feed is intermittent or the belt speed is high enough to make the bed unstable
16 to 22 deg	Standard chevron or shallow U-profile, single chevron row	10 to 15 mm	450 to 550 mm	This is the band where cheap profile work pays best. Ribs stop the sliding layer, pocket volume is not yet critical, and the belt can still pass comfortably around standard pulleys
22 to 28 deg	Standard chevron, tighter pitch, abrasion-grade cover underneath	15 to 20 mm	400 to 500 mm	Pocket filling starts to matter and the rib face begins to see real dynamic load; this is where pitch selection separates a quiet installation from a noisy one
28 to 34 deg	Deep chevron, with transverse dividers on materials that flow readily	20 to 30 mm	350 to 450 mm	Above roughly 28 deg the rib stops being a stop and becomes a wall the load leans on for the full travel time; the belt runs full and the pocket becomes the transport volume
34 to 40 deg	Deep chevron plus cross dividers, coarse single-layer loading only	25 to 35 mm	300 to 400 mm	The pockets must be filled by a chute that delivers material into them, not dumped onto the belt in a pile; an unfilled pocket on a 36 deg incline is a chute wearing a belt
Above 40 deg	Not this family at all — cross-rigid carcass with moulded sidewalls	Sidewall height replaces rib height entirely	Cleat pitch now works with the sidewall base width	A rib cannot enclose a bed, so material that can flow sideways will; enclosure is the only answer and it changes the belt construction, the pulleys and the support structure

There is also a supplier-side reality that belongs in this conversation. A conveyor belt factory can only quote pitches its moulds actually cover. Ours spans a defined set of standard pitch and height combinations, and asking for 17 mm at 430 mm will get you either the nearest standard moulding or a moulding cost that changes the whole commercial argument. Buyers who know that in advance specify inside the range used for wholesale conveyor belts and get both the right geometry and a normal price.

Where the plant wants repeat supply with no engineering input at the ordering stage, the sensible arrangement is a conveyor belt distributor arrangement in which the profile, pitch and splice layout are fixed once and then reordered by part number. We do that for a number of quarries and terminals, and the value is not in the price of the belt; it is that the second belt is identical to the first one.

One more comparison is worth making for plants that run both kinds of drive. The compound and cord discipline applied to a ribbed belt is the same discipline a V-belt manufacturer has to apply on a much smaller scale, where a few millimetres of cord placement decide whether the belt survives its millionth bend. Anyone specifying a transmission belt manufacturer-grade product for a critical drive already understands the principle: geometry decides life, not the other way round.

With the family and the material settled, the numbers look like this.

Material	Bulk density (t/m³)	Dominant lump size	Profile to quote	Rib height and pitch	The trap specific to this material
Sized coal, washed	0.80 to 0.90	0 to 50 mm, occasional 150 mm	Standard chevron with a tight pitch	15 to 20 mm at 350 to 450 mm	Dust and fines pack into the valley between ribs and are not touched by a standard scraper, so the belt carries material back under the whole return run
Crushed limestone and aggregate	1.35 to 1.55	0 to 40 mm, up to 120 mm with poor screening	Standard to deep chevron	15 to 25 mm at 400 to 500 mm	Oversize pieces sitting on top of the rib array wear the rib crest and the rib face into a smooth ramp, after which the profile stops stopping anything
Sand and gravel, dry	1.45 to 1.60	0 to 20 mm, rounded	Standard chevron	12 to 18 mm at 400 to 500 mm	Rounded grains roll over shallow ribs like water over a weir; if the pocket is not deep enough to hold a full bed depth, the belt looks correct and still spills
Cement clinker, hot	1.25 to 1.45	0 to 30 mm, abrasive	Deep chevron on a heat-grade base	20 to 28 mm at 350 to 450 mm	The rib root is the hottest point on the belt because it holds material against the cover, and thermal cycling there ages the bond line faster than the rest of the surface
Grain, oilseed and pellets	0.65 to 0.80	Free-flowing, under 10 mm	Shallow chevron or U-profile, short pitch	8 to 15 mm at 250 to 350 mm	The whole bed flows as one body, so a tall rib helps less than a short rib repeated more often; also check that the profile is food-contact acceptable for the crop being handled

04Rib and Divider Combinations: Building Pockets That Hold

Ribs alone work because a sliding bed gets interrupted. That is enough up to about 30 degrees. Past that point the load behaves less like a bed being slowed and more like a mass being carried, and the weak direction is no longer down the belt — it is along the belt, where a V-shaped rib leaves two open channels that material can flow along on either side of the apex. A chevron profile carries a bed. It does not enclose one.

Transverse dividers close the pocket. A divider is a cleat running across the belt, moulded between or across the chevron arms, so that each pitch becomes a shallow box with the belt surface as its floor and the ribs as its sides. The combination — chevron for the shape of the side walls, divider for the front wall — is what allows a single belt to climb 32 or 36 degrees without a sidewall construction.

The geometry then has to be checked as a volume, not as a height. Take a 1,000 mm belt with 80 mm margins at each edge, so 840 mm of usable width. A 30 mm rib at 400 mm pitch gives a pocket of roughly 0.030 × 0.400 × 0.840, which is about 10 litres of geometric volume. Real filling is never complete; for coarse angular material we would assume 60 to 75 percent of that volume actually stays in the pocket at the point of maximum slope, so somewhere between 6 and 7.5 litres per pocket. If the belt runs at 1.6 m/s with a 400 mm pitch, four pockets pass per second, giving roughly 0.028 m³/s of carried material. Limestone at 1.45 t/m³ then works out at about 145 t/h. Change the pitch to 500 mm without touching the rib height and that figure drops by a fifth, which is the whole argument for treating pitch as a capacity variable rather than a moulding detail.

Dividing the belt into pockets has a consequence at the discharge end that catches people who have only ever run flat belts. A pocket belt discharges in slugs, not in a stream.

Each pocket arrives at the head pulley and dumps its content as one discrete mass, so the trajectory calculation and the discharge chute have to be designed around a sequence of impacts rather than a continuous flow. On a 32 degree limestone incline in a quarry we visited, the chute had been sized from the belt capacity in tonnes per hour and was uniformly too short. Material was landing on the far wall of the chute at roughly 4 m/s four times a second, which had worn a hole through 8 mm plate in under a year. Lengthening the chute and adding a dead-box solved it; the belt had been blamed first.

The base belt has to be chosen with the dividers in mind as well. A transverse divider transmits its load straight into the carcass along a line, and if the carcass has no transverse strength the cleat effectively pulls the belt apart along that line. That is why pocket belts are built on a cross-rigid construction with a breaker ply or a transverse-reinforced carcass, and why a cover grade chosen purely for abrasion resistance is not automatically the right choice — the material also has to survive the impact of the loading stream. Our impact and cut resistant conveyor belt range exists for exactly this combination of force directions, and the abrasion side of the same question is set out on the abrasion resistant conveyor belt page.

How the pocket is supported underneath is the other half of the design, and it is the part most often left to the last minute. A deeply cleated belt cannot be troughed; the dividers and ribs will not deform into a 35 degree trough, and forcing them to do so tears the profile off the cover within weeks. Pocket belts normally run on flat or very shallow carrying idlers, which reduces the loaded cross-section and therefore raises the required belt speed or belt width. The return side needs the same attention, because the ribs ride on the return idlers instead of the flat cover, and the belt then has an effective thickness equal to the rib height at those points.

Whether the plant can actually feed a pocket belt evenly is worth settling before the order, not after. Where the feed is an existing short chute from a crusher, the stream arrives with velocity, spreads unevenly across the width and fills some pockets while leaving others empty. Empty pockets on a steep incline are not a capacity loss; they are a maintenance item, because the belt and the chute then absorb the energy the material would have carried. A conveyor components review of the loading station, the skirt arrangement and the belt support is usually money better spent than an extra millimetre of rib height. When the duty is repeat and the geometry should not be re-argued every time, the practical route is to place the line standard with a single conveyor belt supplier who holds the splice drawing and the profile specification on file.

Belt width	Usable width between 80 mm margins	Rib height and pitch	Geometric pocket volume	Carried volume at 70 percent fill	Approximate tonnage at 1.6 m/s and 1.45 t/m³
800 mm	640 mm	20 mm at 400 mm	5.1 litres per pocket	3.6 litres per pocket	About 84 t/h, and this is often below what a 800 mm line was bought to do
1,000 mm	840 mm	30 mm at 400 mm	10.1 litres per pocket	7.1 litres per pocket	About 148 t/h with four pockets passing per second
1,200 mm	1,040 mm	30 mm at 450 mm	14.0 litres per pocket	9.8 litres per pocket	About 182 t/h, with dividers needed past roughly 30 deg

Chevron cleated conveyor belt carrying aggregate up an inclined conveyor at a quarry plant

Those tonnages assume the material sits in the pockets. In practice the number that decides whether the installation reaches design capacity is how much material the chute can place inside a moving pocket during the fraction of a second the pocket is under the loading point. At 1.6 m/s and a 400 mm pitch, each pocket is under a 600 mm long loading zone for about 0.375 seconds. Nothing about the belt specification changes that number.

05The Base Belt Under a Cleated Top Cover

Everything above has been about the top surface. The belt that has to survive underneath it is a separate specification, and on inclined haulage it is usually working harder than the equivalent flat-run belt at the same tonnage. Three reasons. The material rides higher on the belt, so the centre of gravity of the load is further from the idler line. The belt runs closer to full, so the load per metre is higher. And the whole lift component of the load, which on a level run is zero, now has to be carried as belt tension all the way back to the tail.

The lift tension is easy to underestimate. Every tonne per hour raised through a given height adds tension to the belt that has nothing to do with friction, and the steeper the incline the larger the share of total tension that lift accounts for. On a 25 degree line handling a full bed, it is common for the lifting component to be a third or more of the total running tension. That is why an incline project can end up needing one more ply than the tonnage alone would suggest, and why the ply count should never be copied from the horizontal conveyor upstream.

Cover grade is the second half of the base specification, and on a ribbed belt it deserves more care than usual. The cover is not just the wear surface; it is the foundation the rib is moulded onto, and every kilogram of material leaning on a rib arrives at the cover as a peel load along the rib root. A soft, compliant cover absorbs that load better on day one and wears through faster by month twenty. An abrasion-grade compound with a DIN 22102 abrasion loss at or below roughly 90 mm³ gives the rib root something firm to sit on and a valley that resists grooving, which matters because the valley between ribs is where wear always shows first.

Steel cord bases enter the picture on long, high-lift overland inclines where the tension requirement pushes fabric plies past a practical count. A steel cord construction will carry the load with fewer, thicker components and much lower elongation, which helps keep the take-up stroke reasonable. The trade is that steel cord belts demand larger pulleys and more careful splice work, and the profile has to be moulded onto a cover that was designed for cord adhesion. The fire resistant conveyor belt family, the heat resistant conveyor belt grades, the oil resistant conveyor belt compounds and the chemical resistant conveyor belt options are all available as bases for a ribbed top cover, and the steel cord conveyor belt construction is the one to reach for once lift tension dominates.

All of that comes together in one number that kills more ribbed belt installations than any other: the minimum pulley diameter.

The base belt has its own minimum pulley diameter, set by carcass type, ply count and working tension, and the values in the standard tables assume a flat cover. Add ribs and the belt becomes a thick, uneven laminate at the point of bending. The rib base has to compress on the inside of the bend and stretch on the outside, and it does that around a radius the rib was never moulded for. As a shop rule we take the larger of the base belt's own minimum and roughly twenty times the clear rib height, and we would rather increase a pulley than reduce a rib. Twenty times 25 mm is 500 mm, and on a 1,000 mm belt that is a realistic minimum for a deep profile.

We learned that on a 1,000 mm three-ply line at 24 degrees where the head pulley was 400 mm and the ribs were 25 mm tall. Ribs started cracking along the root line at eleven months, and the crack pattern ran exactly along the rib rather than across it — the signature of bending fatigue rather than of a bad bond. Nothing about the belt compound was wrong. The pulley was. Replacing the head pulley with a 630 mm unit and keeping the same profile took the same installation past three years on the next belt.

06Splicing, Rib Attachment and On-Site Fit-Up

A ribbed belt is usually delivered open-ended and joined where it will run, and that joint is where more incline projects lose time than anywhere else. On a flat belt, a splice is a splice. On a ribbed belt, the splice and the ribs have to be reconciled, because the ribs are proud of the surface and any joint that passes through them has to be arranged so that the profile survives both the vulcanizing press and every subsequent pass over the pulleys.

The convention that works best is to leave the rib rows clear of the splice. Instead of running a rib row through the joint, the profile is stopped short on both ends, leaving a flat band of 200 to 300 mm that the press can work and the pulleys can bend cleanly. The cost is a loss of pocket volume at the joint, and on a short belt with few pockets the flat band can be a real capacity penalty; on a long overcline it is invisible. Suppliers who run ribs straight through the splice are relying on the joint being made in a moulded valley, and that needs a press and a splice drawing capable of holding the rib geometry while the plies are joined.

Mechanical hinged fasteners, the plate-and-pin type that can be fitted in an afternoon with hand tools, are effectively out of scope here. A hinge cannot climb over a cleat row, and the rib section bridging the fastener concentrates the bending into a strip of belt that is already perforated. Where a ribbed belt has to be joined in a hurry, the practical fallback is a vulcanized joint or a belt with no ribs at the splice and a separate cleat-bolting operation afterwards.

Which brings the cleats themselves. Factory-moulded ribs are vulcanized into the cover under heat and pressure, and that is the bond the profile was designed around. Hot vulcanizing cleats onto an already-spliced belt in a site press is the next best thing and is common where cleats must be placed to suit the pulley spacing. Cold-bonded adhesive attachment is best kept for repairs and for the occasional replacement rib; it can be made to work, but on a belt that passes the head pulley a few thousand times an hour the adhesive layer is the first thing to give, and it gives progressively rather than all at once. Bolt-on cleats are a legitimate design on some heavy installations and are very convenient in the field, but every bolt hole is a stress raiser and a water path into the carcass.

Hot vulcanizing a rib onto a chevron cleated conveyor belt cover in the factory

Once the belt is made up and tensioned, the running gear decides whether the profile lasts. Carrying idlers on a ribbed belt should be flat or shallow — two-roll sets at 10 to 20 degrees are the upper limit, and anything approaching a 35 degree trough will fight the rib layout. Flat carrying idlers are less efficient at containing the load, so the belt either runs narrower or faster to carry the same tonnage, and that is a decision to make at design stage rather than in the workshop. Idler spacing on an inclined run is usually tighter than on the level because the belt has a lift component pulling it toward a straighter line between idlers, which reduces the sag available to absorb impact at the loading point.

Rib and splice method	Where it is the right answer	Strength retained at the rib	Site requirement	Failure signature to watch for
Factory-moulded ribs with a hot vulcanized stepped splice between rib rows	New long belts where capacity loss at one joint is irrelevant	Best available; the rib bond is the same as the rest of the belt	Site vulcanizing press with a splice drawing, plus a flat band 200–300 mm long kept clear of ribs	Splice edge lifting at the flat band, usually on the leading side of the joint where the load crosses
Factory-moulded ribs with the rib row run through the vulcanized joint	Short belts where every pocket counts and the splice geometry is known	High if the press and moulding are right, lower if the joint is made in a rib crest instead of a valley	Specialist tooling that holds the rib profile during cure; not a general-purpose splice job	A rib that stands slightly proud or low at the joint, followed by fast wear on that single rib
Cleats hot vulcanized on site after the belt is spliced	Retrofits, and cases where cleat spacing must match pulley positions	Close to factory bond if the press, temperature and cure time are controlled	Site press, accurate jigs for spacing, and a clean, dry, freshly buffed cover	Cleats that peel progressively from one end, typically the end that reaches the pulley first
Cleats cold bonded with two-part adhesive	Single rib replacements and emergency repairs on a stopped line	Moderate at best, and highly dependent on surface preparation	No press needed, but full cure time before the belt runs, which is rarely available on a live line	A clean separation between rib and cover with adhesive residue on one side only
Bolt-on cleats and dividers through a plain belt	Heavy cleats, field-adjustable pocket spacing, and some mobile plant	Good in shear, weaker in fatigue because the holes interrupt the plies	Workshop drilling with a template, correct bolt grades and controlled torque	Wet rust streaks from the bolt line and a crack running between adjacent holes

If none of this is going to be handled in-house, say so early. Belt changing on an incline is a different job from belt changing on the level, and the running gear around it — carrying idlers, return sets, impact rollers, pulleys and brackets — all have to be compatible with a ribbed belt. Our conveyor rollers range, the troughing idler and return idler families, the impact idler sets for the loading zone, self-aligning idler options for the return run, the conveyor pulleys that set the bending radius and the conveyor brackets that tie the whole frame together are all specified from the same drawings, and getting them from one source removes a class of compatibility argument that is expensive to settle on site. Where the plant would rather hand the whole job over, our service scope covers survey, belt selection, splice planning and fitting support.

07Failure Modes on Inclined Haulage and What They Tell You

A ribbed belt usually fails for one of four reasons, and the reason is almost always visible in the wear pattern long before the belt stops working. The first is that the profile was the wrong size for the material, so the belt never really carried the load in its pockets. The second is that the rib root was overloaded by pulley geometry, which produces cracks that run along the rib rather than across it. The third is that the bond between rib and cover was made in a way the duty does not forgive. The fourth has nothing to do with the belt at all and everything to do with how material arrives at it.

Carry-back on an incline is under-appreciated because it is invisible from the walkway. Material that stays in a pocket past the discharge point falls out somewhere along the return run, usually onto the ground under the conveyor or into the tail area, and it takes a long time to be noticed. Pockets make this worse by design; they are, after all, containers. On a coal or clinker line, brush cleaners and a properly shaped discharge chute do more for housekeeping than any change to the belt, and the amount of material sitting between the ribs at the point where the belt passes the scraper is the number worth measuring. The mechanics of idler sealing matter here too, since a ribbon of fine material riding back over the return rollers will find its way into bearings sooner or later.

Tracking on a ribbed belt occupies an unreasonable share of maintenance attention, and the diagnosis is usually structural. The profile itself does not steer the belt. What steers it is contact geometry, and the contact geometry on the return run of a ribbed belt is the crests of the ribs rather than the full belt width. Two things follow. First, the return idlers must be level relative to each other to a tighter tolerance than a flat belt would need. Second, anything that lets the ribs meet the rollers at an angle will produce a drift that no amount of head-pulley lagging will cure.

Symptom on the belt	Most likely cause on an incline	First thing to measure	Corrective action that works	How to avoid it next time
Rib crests polished flat, valleys still intact	Bed depth exceeds usable pocket volume, so oversize material rides over the profile	Depth of material at the point of maximum incline and the 95th percentile lump size	Reduce bed depth, raise rib height, or shorten the pitch to add pockets per metre	Size rib height against the largest lump and pitch against measured tonnage, not against a stocked profile
Cracks running lengthwise along the rib root, on many rows	Bending fatigue; the rib is being forced around a pulley smaller than the profile needs	Diameter of the smallest pulley passed and the ratio of that figure to clear rib height	Increase pulley diameter, or reduce rib height, or both if the lift allows it	Set pulley diameter from the larger of the base belt minimum and roughly twenty times the rib height before the belt is ordered
One or two cleats peeling from a single end	Localised bond failure, often after a cold-bonded repair or a damaged cover under the cleat	Why that cleat was replaced, and how much compound was left on the cover surface	Re-bond by hot vulcanizing, or replace the cleat row properly rather than gluing the lifted end	Keep cold-bonded attachment for genuine emergencies, and record every repair so patterns emerge
Material on the ground under the return run and at the tail	Carry-back from pockets, plus a cleaner that cannot reach between the ribs	Depth of material sitting in the pockets just after the discharge point	Fit a rotary brush or air-knife type cleaner suited to a ribbed surface instead of a single scraper	Allow cleanability as a selection criterion at design stage; shallow pockets clean, deep ones hold

08The RFQ Sheet: Data a Belt Maker Needs for Inclined Duty

Most incline enquiries arrive as a belt width, a length and a slope angle, which is about half of what is needed. The consequence is a quotation that answers a slightly different question from the one the plant asked, followed by three rounds of technical clarification and a belt that is nearly right. Sending the full data set in the first message typically removes two weeks from the process.

Our own enquiries go through the same checklist for every angled line, and the belt specification that comes out the other end is traceable back to each entry. It is also the checklist we use when a plant asks us to survey an existing incline where the belt is being replaced for the third time, because the missing data is usually the reason the previous two belts did not work. The underlying discipline is the same as any engineered component purchase, and it is set out more broadly in our guide to conveyor belt types, grades and how to choose, which is worth reading alongside this page if the incline is part of a wider project.

Data item to send	Why it changes the belt specification	Typical entry	What goes wrong when it is left out
Steepest incline angle, and how long that section is	Sets the profile family, and therefore whether dividers are needed at all	24 deg over 38 m, with flatter approach sections at 6 deg	A profile is quoted for the average angle instead of the worst one, and the steep section spills
Lift height and centre distance	Determines the tension contributed by lifting the load, which drives ply count	15 m lift over a 62 m centre distance	Ply count is taken from a similar horizontal conveyor and the belt is under-strength from day one
Design capacity in tonnes per hour, and the peak	Sets pocket volume, so it decides rib height, pitch and belt width together	180 t/h average, 240 t/h for short periods at shift change	The belt is sized on average tonnage and runs permanently over-full at peaks
Bulk density and the 95th percentile lump size	Converts volume into tonnage, and sets the minimum rib height that will clear the largest pieces	1.45 t/m³ loose, 90 percent below 40 mm with 120 mm oversize	Rib height is chosen against the average lump and oversize material rides over the crests
Smallest pulley diameter the belt will pass	Caps the rib height, and is therefore the first constraint to check on any retrofit	Head 500 mm, tail 400 mm, both existing and not being replaced	A deep profile is quoted that the pulleys cannot bend, and the ribs crack along their length
Take-up type and available stroke	Governs whether elongation can be absorbed without slipping on the incline	Screw take-up with 300 mm of travel remaining	The belt loses tension after a few months and starts to slip when the incline is fully loaded
Loading chute geometry and drop height	Sets whether pockets can be filled, and how much impact the cover has to absorb	600 mm long chute, 900 mm drop, discharge roughly square to the belt	The belt is designed for a filling pattern the chute cannot deliver, and capacity is never reached
Environment and any statutory requirement	Drives compound selection, flame retardance and, in some cases, the whole construction	Outdoor, washdown weekly, enclosed transfer tower with a dust atmosphere	A flame-retardant requirement is discovered at inspection and the belt has to be replaced

If the project also has to consider the wider handling chain, our application pages for mining and quarrying, cement plants, port bulk material handling, recycling, food packaging and logistics and warehousing show how the profile decision sits inside a larger layout. The main product page for the belt itself is chevron conveyor belt, and the profile tolerances and batch records behind it are covered under quality assurance.

One closing observation from enough of these projects to be worth stating plainly. The choices that decide whether an inclined conveyor works are made in the first hour of the specification, and they are all geometry: angle, rib height, pitch, pulley diameter, pocket volume. Compound and cover grade matter, but they are refinements. Get the geometry wrong and no compound will save the installation; get it right and even a modest cover will give years of service.

Send your incline data and we will recommend a profile

09Frequently Asked Questions

What is the steepest incline these belts can handle?

With ribs alone, roughly 30 to 34 degrees for coarse, angular material and less for free-flowing product. Adding transverse dividers extends the working range to about 40 degrees. Beyond that the material has to be enclosed, and the belt becomes a cross-rigid construction with moulded sidewalls rather than a profiled single belt.

How do I choose rib height for my material?

Start from the largest lump rather than the average. We want the clear rib height to be at least 1.5 times the 95th percentile lump size, because anything shorter lets oversize pieces bridge the pocket and ride over the crests. Then check the resulting height against the pulleys, since rib height caps the smallest pulley the belt can pass.

Do I really need transverse dividers as well as ribs?

Above roughly 28 to 30 degrees, yes, and on free-flowing materials such as grain or sand at lower angles too. A chevron pattern holds a bed but leaves open channels along the belt; a divider closes each pitch into a pocket. Dividers also require a carcass with transverse strength, so the base belt changes when you add them.

Why are my ribs cracking along their length rather than across?

That pattern is bending fatigue, not a compound fault. It means the rib is being forced around a pulley smaller than the profile needs. Check the diameter of the smallest pulley and compare it with the rib height; as a shop rule the diameter should be at least twenty times the clear rib height, and never below the base belt's own minimum.

Can the joint be made on site with a mechanical fastener?

Not on a profiled belt. A hinge-type fastener cannot climb over a cleat row, and the perforated strip under it concentrates bending exactly where the belt is weakest. Site joints should be vulcanized, with the profile kept clear of the splice band, or the cleats attached after splicing by hot vulcanizing.

How should the return side be supported and cleaned?

The ribs travel against the idlers, so the belt contacts the roller through the rib crests and rides higher than a flat belt would. Use flat return idlers of generous diameter, keep adjacent idlers level to a tight tolerance, and clean with a rotary brush or air knife rather than a single scraper, which cannot reach the material sitting between the ribs.