Question 1

It depends mainly on pitch, width, pulley diameter and speed: small pitches carry a few kilowatts, mid sizes tens of kilowatts, and large 8M to 14M industrial belts reach into the hundreds of kilowatts. The practical method is to pick a pitch from the duty, then size the width with a service factor against the rating tables of the actual belt type.

Accepted Answer

Direct answer: There is no single number: capacity is set by pitch, width, pulley diameter and speed together. Small pitches transmit a few kilowatts, mid pitches tens of kilowatts, and wide 8M to 14M industrial belts can reach into the hundreds of kilowatts. Correct sizing always goes through the rating tables of the specific belt type, corrected by a service factor.An H-pitch belt like 400H-225 sits in the classic tens-of-kilowatts industrial range.What actually sets the capacityPitch and tooth form: a bigger pitch means longer teeth in contact and more torque carried per tooth.Belt width: capacity scales close to linearly with width, which is why width is the usual sizing lever once the pitch is chosen.Pulley diameter: larger pulleys wrap more teeth and bend the belt less, so they allow more power per unit width.Speed: transmitted power rises with speed at first, then centrifugal effects and heat build-up limit further gains.Duty conditions: shock loads, frequent starts, high ambient temperature and backside idlers all reduce the usable rating.Wide 8M belts such as 8M-2320-35 are the workhorses of heavy industrial drives.Typical industrial power ranges by pitch familyPitch familyTypical useRough power range at moderate speedMXL, XL, LOffice machines, small appliances, light conveyorsFractions of a kW up to roughly 10 kWH, XHIndustrial machinery, pumps, compressorsRoughly 10 kW up to around 100 kW3M to 5MCompact drives, power tools, small equipmentFractions of a kW up to around 20 kW8MHeavy industrial drivesTens of kW up to roughly 150 kW14MLarge high-power drivesHundreds of kW in wide buildsS8M-984-50: the S8M family is common in high-torque industrial drives. These ranges are for orientation only. Final sizing uses the rating tables of the actual belt type, corrected with a service factor for the driven machine, start frequency and ambient conditions. Guessing a width without the service factor is the fastest route to premature tooth shear.Have us size the driveEmail sales@goodlybelts.com with the motor power, speed ratio, centre distance and duty cycle, or use the enquiry form. We will propose pitch, width and pulley sizes and confirm the rating against the actual belt data.Size my drive

Question 2

Usually yes, provided the pulley teeth still have full flanks, no hooked tips and no visible wear steps. A worn pulley chews up a new belt within weeks, so inspect the tooth flanks, tips, flanges and alignment before fitting the new belt. When in doubt, replacing pulleys together with the belt is the cheaper option over a full service life.

Accepted Answer

Direct answer: Yes in most cases: if the tooth flanks are smooth, the tips are sharp and undamaged, and the flanges are straight, the pulleys can stay in service. The exception matters, though, because a worn pulley destroys a new belt far faster than the old belt wore out. A five-minute inspection decides it.Tooth contact happens on the flanks: that is exactly where wear shows first (8M-1304-30 belt).What to check on an old pulleyCheckPassReplace the pulley ifTooth flanksSmooth, slightly polished surfacesVisible wear steps or a concave, rounded profileTooth tipsSharp and even all roundHooked or rolled-over tipsFlangesUndamaged, belt runs centredBent, chipped, or leaving marks on the belt edgeAlignmentShafts parallel, pulleys in lineBelt persistently tracks to one sideBore and keywayTight, no movement on the shaftLoose fit, play, or a cracked hubEven tooth engagement like this (8M-1624-30) is what a healthy pulley gives a new belt.Why worn pulleys kill new belts earlyFlank wear effectively enlarges the pulley pitch, so the new belt no longer sits correctly in the teeth. Load then concentrates on a few teeth instead of spreading across the wrap, and the belt cord fatigues in one spot. Add debris sitting in worn grooves and a slight misalignment, and the new belt loses weeks of life for every month the pulley problem continues.Rules of thumbReplace pulley and belt together on critical or hard-to-access drives. A second stop costs more than a pulley.If a belt failed well before its expected life, suspect the pulleys first: wear, misalignment and debris are the three most common hidden causes.A quick wear test: fit the new belt by hand and rock it in the teeth. Excessive radial play means the effective pitch has grown past its limit.Aluminium pulleys wear faster than steel ones. On high-torque drives, inspect them more often.Belt and pulley wear as a system: 120L-25 belt shown with its mating tooth form.Send a photo of the pulleysEmail sales@goodlybelts.com with photos of the old pulley teeth and your belt details, or use the enquiry form. We will help you judge whether the pulleys are fit for the new belt and confirm the correct replacement belt at the same time.Have my pulleys checked

Question 3

Timing belt noise usually comes from wrong tension, pulley misalignment, worn or wrong-profile teeth, or a trapezoidal profile running where a curvilinear one would be smoother. High belt tension whines, low tension rattles and ratchets. Re-tension to spec and align the pulleys first; profile and pitch choice handle the rest.

Accepted Answer

Direct answer: A whining belt is usually over-tensioned or misaligned; a rattling or slapping belt is usually under-tensioned or carrying shock loads; a constant high-pitched tone that grows with speed often points to tooth profile mismatch or a worn pulley. Fix tension and alignment first, because they cause most noise complaints, then look at profile and pitch.Milling-machine drives like this 2J650-30 belt tolerate very little noise: alignment and tension are critical.Find the noise type firstNoiseTypical causeFirst actionContinuous whine, rises with speedToo much tension, or stiff small-pitch belt on large pulleysRecheck tension against spec, not by feelRattle or slapping in the spanToo little tension, or resonance of a long spanTension to spec; consider an idler on the slack spanChirping or ticking per revolutionLocal tooth damage, debris in the mesh, or a dented pulley toothInspect teeth and clean the meshLoud engagement, worse at high RPMTrapezoidal profile (T, XL, L) engaging sharply, or profile mismatchConsider curvilinear HTD/STPD profiles where the machine allowsGrowl that vibrates through the framePulley misalignment or bent shaftLaser or ruler check across pulley facesXL and L trapezoidal belts (390XL-155) engage more sharply than curvilinear profiles.Checks that take minutes, not hoursTension: use a deflection gauge or frequency meter. Feeling by hand is why most drives run too tight.Alignment: lay a straight edge across both pulley faces. Even one or two degrees of angular misalignment creates a whine and wears flanges.Tooth tips: shiny or rounded belt tooth tips and matching pulley valleys mean the profile or pitch is wrong or the belt was made for a different pulley.Debris: dust paste in the tooth mesh ticks at mesh frequency. Clean the drive, especially in wood, stone or paper applications.Span resonance: on long spans, a light idler on the slack side changes the resonance and often silences the rattle.Wide 14M belts (14M-5880-40) carry heavy load quietly when the pulleys are aligned and tensioned right. Noise fixes must not come from removing too much tension. A belt that runs silent because it is loose will jump teeth under load, and the repair is far more expensive than a whistle.Noise you cannot pin down?Send the belt code, pulley tooth counts, centre distance and a short description of when the noise occurs to sales@goodlybelts.com, or use the enquiry form. We will help identify the cause and propose a quieter construction if needed.Ask about the noise

Question 4

Match the pulley pitch to the belt first, then check three numbers: at least the minimum recommended tooth count for your belt and speed, an outside diameter that keeps the belt inside its bending limits, and flanges tall enough to keep the belt on the pulley. Material and hub style come last: steel or aluminium for power drives, aluminium or plastics for light and high-speed duty.

Accepted Answer

Direct answer: The pulley pitch profile must match the belt exactly: an 8M belt runs only on 8M pulleys, and HTD and STPD are not interchangeable. Then respect the minimum tooth count recommended for that belt at your speed, keep flanges on both sides of at least one pulley (better both pulleys), and choose a material that suits the torque and speed. Getting the pitch right but ignoring tooth count is the most common drive error we see.This 8M-1640-30 belt only meshes correctly with HTD 8M pulleys.The four checks, in orderCheckRule of thumbWhy it mattersPitch and profileIdentical designation on belt and pulley: 8M with 8M, S8M with S8M, AT10 with AT10Similar-looking curvilinear profiles do not mesh; mismatch destroys teeth within hoursMinimum tooth countStay at or above the belt manufacturer minimum for the pitch and RPM, small pulleys at high speed need more teethToo few teeth in mesh overloads the few engaged teeth and rips cordsFlangesFlange both sides of at least one pulley; flange both pulleys on vertical or reversing drivesFlanges keep the belt captive; without them the belt walks off at the first misalignmentMaterial and boreSteel or aluminium for power duty, aluminium or engineering plastic for light, fast, quiet drivesPulley deformation or bore play shows up as vibration and uneven belt wearSmall-pitch belts like S3M-300 need accurate small pulleys with enough teeth in mesh.Details buyers often forgetPitch diameter and outside diameter are different numbers: the belt rides on the pitch diameter, the flange sits on the outside diameter.Keyways, set screws, taper bushings or clamp collars: choose the hub style before ordering, retrofitting is annoying.For idlers, use flanged idlers on the back of the belt or toothed idlers inside the span; smooth idlers on the tooth side wear the teeth.Check the pulley width against the belt width: the belt needs lateral play inside the flanges, typically a few millimetres.When replacing a belt on existing pulleys, measure the pulley outer diameter and count the teeth, and inspect the tooth tips for wear: new belts on worn pulleys die young.S5M-220, a typical light-drive pitch where quiet running and flange quality matter. If your drive must be rebuilt from scratch, sending us the motor power, RPM and centre distance is enough for us to propose belt and pulley sizes together, so the two orders cannot drift apart.Need pulleys matched to your belts?Email the belt code, tooth counts or drive data to sales@goodlybelts.com, or use the enquiry form. We will propose matching pulleys and quote belt and pulleys as one set.Request matched pulleys

Question 5

There is no fixed calendar life for a timing belt: in a clean, correctly tensioned drive, rubber timing belts commonly run for many thousands of hours, while hot, oily or abrasive conditions can cut that sharply. Replace by evidence, not by date: inspect at set intervals and change the belt at the first clear signs of cracking at tooth roots, cord exposure, hardened underside or tooth-tip wear.

Accepted Answer

Direct answer: A timing belt is replaced by condition, not by calendar. In a clean, aligned, correctly tensioned drive, rubber timing belts commonly give many thousands of hours of service, but heat, oil, dust and misalignment can shorten that dramatically. Inspect at fixed intervals and replace at the first clear wear signs, rather than waiting for a failure.A correctly tensioned belt wears slowly and predictably (120L-25).What decides how long a belt lastsTension and alignmentThe two biggest factors. Over-tension heats and fatigues the cord; misalignment wears one edge and can ratchet teeth.EnvironmentHeat, oil mist, abrasive dust and direct sunlight all age the rubber compound faster than the calendar suggests.Pulley conditionWorn pulley teeth accelerate belt wear. Belt and pulley wear each other, so always assess them together.Load characterFrequent starts, shock loads and back-bending idlers shorten life compared with a steady, lightly loaded drive.Heavier sections such as H carry more load but reward good tensioning (400H-225).Signs it is time to replace nowCracks at the tooth roots, visible when the belt is flexed at one tooth.Cord lines showing through the tooth surface, or a frayed edge.A glazed, hardened or sticky back surface, which signals heat or chemical ageing.Tooth tips flattened or worn across the working face.New noise, such as slapping or a rhythmic ticking, that tracking and tension do not cure.A practical inspection routineDutyInspection intervalTypical preventive replacement windowLight, clean dutyEvery 6 monthsReplace on evidence, often well beyond a year of runningGeneral industrial dutyEvery 3 monthsReplace at first clear wear signs; plan a spare per machineHot, oily or dusty dutyMonthlyShorter intervals; consider a more resistant compound insteadAfter any failure eventImmediatelyFind the root cause before fitting the new belt Never fit a new belt alongside a used one or onto worn pulleys without checking them. Most premature belt failures trace back to tension, alignment or pulley wear, and a like-for-like replacement fails the same way.Keep one inspected spare per critical machine so evidence-based replacement never waits for shipping (S8M-984-50).Want a longer-lasting belt for your duty?Send your application details, environment and current failure pattern to sales@goodlybelts.com. We will suggest the compound, cord and tension practice that best matches your drive.Ask for a belt review

Question 6

A code such as 800-8M-30 reads as 800 mm pitch length, 8M profile with an 8 mm pitch, and 30 mm belt width. Imperial codes work the same way but in inches, so 320L075 means 32.0 inch pitch length, L profile and 0.75 inch width. Pitch length is measured on the cord line, so it never matches a tape measure run around the outside of the belt.

Accepted Answer

Direct answer: 800-8M-30 means 800 mm pitch length, 8M tooth profile on an 8 mm pitch, and 30 mm width. Metric codes read length first, then profile, then width; imperial codes put the profile letter after the length in inches and the width in hundredths of an inch.The same data in a different order: 8M-2320-35 is an 8M belt, 2320 mm pitch length, 35 mm wide.Decoding metric and imperial codesCodePitch lengthProfileWidth800-8M-30800 mm8M, 8 mm pitch30 mm2320-14M-402320 mm14M, 14 mm pitch40 mm320L07532.0 in (812.8 mm)L, 3/8 in pitch0.75 in (19.05 mm)120XL02512.0 in (304.8 mm)XL, 1/5 in pitch0.25 in (6.35 mm)450H10045.0 in (1143.0 mm)H, 1/2 in pitch1.00 in (25.4 mm)Common profiles and their pitchesProfilePitchTypical useMXL2.032 mmSmall instruments and light drivesXL5.08 mmLight duty machineryL9.525 mmGeneral light industrial drivesH12.7 mmMedium load drives3M / 5M / 8M / 14M3 / 5 / 8 / 14 mmMetric drives from light to heavy dutyAT, STD, RPPMetric, modified tooth formHigher load, quieter running, positioning drivesWhy the length on the belt is not what you measureTiming belt length is the pitch length, measured along the cord line inside the belt. A tape run around the outside gives a different number, and a worn or stretched belt reads longer than its code. If the marking has gone, measure the width and count the teeth: pitch length equals the number of teeth multiplied by the pitch. A 1624 mm 8M belt therefore has 203 teeth.8M-1624-30: 1624 mm pitch length, 203 teeth, 30 mm wide. Profile letters are not freely interchangeable. An 8M pulley and an S8M belt share the 8 mm pitch but not the tooth form, and imperial L and metric 8M belts are not substitutes. Send the full code plus a photo of the pulley teeth when you order.S8M runs on the same 8 mm pitch as 8M but with a different tooth form, so always order by the full code (S8M-984-50).How to specify a belt when the code is worn offMeasure the belt width across the flat back, in millimetres.Count the teeth over the whole belt, then multiply by the pitch to get the pitch length.Identify the profile from the pulley, not from the old belt, because a worn belt can look like a different tooth form.Send one photo of the belt marking and one of the pulley tooth profile and we will confirm the match.Send the code and we will match itEmail the belt code, a photo of the belt and one of the pulley tooth profile, plus the quantity, to sales@goodlybelts.com. We will confirm the profile and length and quote the equivalent GOODLY belt.Check my belt code

Question 7

Choose a timing belt for quiet, oil-free, low-maintenance transmission at normal industrial loads and high speeds; choose a chain for very high torque, shock loads, high heat or abrasive environments. Retrofitting from chain to belt requires new sprockets and a tensioning allowance. Send us your power, RPM and layout and we will confirm which option carries your load with margin.

Accepted Answer

Short answer: Choose a timing belt when you want quiet running, no lubrication and low maintenance at normal industrial loads and speeds. Choose a chain when torque is very high, ambient heat exceeds what rubber compounds tolerate, or the environment is heavily abrasive. Both transmit positive power; the right choice comes down to load, environment and maintenance budget.Where a timing belt is the better choiceQuiet and cleanBelts run far more quietly than chain and need no oil, so nothing drips onto products or floors. Ideal for packaging, food-adjacent and laboratory equipment.Low maintenanceNo lubrication schedule. Tension checks are the main routine, and a well-aligned belt drive often runs its whole design life without adjustment beyond retensioning.High speed capabilityBelts handle high peripheral speeds with less noise and less whip than chain, which is why most high-speed spindle and mixer drives use belts.Washdown friendlyRubber and PU constructions resist washdown and many chemicals far better than bare steel chain, which rusts as soon as the grease is gone.Where chain still winsVery high torque and shock loads: chain handles abrupt starts and heavy shock better than a belt of the same width.High ambient temperatures: standard rubber compounds work comfortably to roughly 80 to 100 degrees C, and special compounds extend that, but chain tolerates heat more easily.Abrasive, gritty environments: sand, scale and chips grind away belt teeth, while a chain can be cleaned and re-lubricated.Very long center distances on a tight budget: chain and sprockets for long spans can cost less than a custom endless belt.FactorTiming beltChainNoiseLowHigher, and it grows as the chain wearsLubricationNoneRequired and ongoingSpeed rangeHigh speeds practicalBest at low to moderate speedsHeat toleranceCompound dependent, roughly up to 80 to 100 degrees C standardHandles higher temperatures more easilyMaintenanceTension checks onlyOiling, adjustment and wear checksOverload behaviourMay jump or break, which can protect the machineStalls the drive or breaks, less forgiving on alignment errorsRetrofitting a chain drive to a beltMany conversions start because of noise or oil contamination. Converting from chain to belt means replacing the sprockets, because belt tooth profiles are not compatible with chain sprockets, and adding a tensioning allowance to the layout. Send us the motor power, RPM, torque profile and a sketch of the drive, and we will propose a pitch and width that carries the load with margin. The figures above are industry-general planning values, not specifications. The right answer depends on your torque profile, duty cycle and environment, so confirm the final choice with a proper drive calculation before reworking the machine.A tensioner makes belt drives forgiving of center distance limits and keeps torque transfer stable.Load, speed and duty cycle decide the choice, not habit. A short drive review usually settles it.Retrofit projects start from the existing layout drawing and end with new sprockets and a matched belt.Not sure which drive fits your machine?Send the power, RPM, center distance and working environment. We will tell you honestly whether a belt is the right call, and which pitch and width we would quote.Ask for a Drive Review

Question 8

For two equal pulleys, belt length is about 2C + 3.14 x D. For different pulley sizes, use L = 2C + 1.57(D1 + D2) + (D2 - D1)^2 / 4C. Round the result to the nearest whole-tooth length, because timing belts are made in pitch multiples, and confirm the center distance can absorb the small difference. Send us the tooth counts and center distance and we will verify the length before quoting.

Accepted Answer

Short answer: For two equal pulleys, belt length is about 2C + 3.14 x D, where C is the center distance and D is the pitch diameter. For unequal pulleys, use L = 2C + 1.57(D1 + D2) + (D2 - D1)^2 / 4C. Then round the result to the nearest available whole-tooth length, because timing belts are made in pitch multiples.The formulasDriveFormulaUse it whenTwo equal pulleysL = 2C + 3.14 x DMirrored drives and idler layouts where both pitch diameters matchTwo different pulleysL = 2C + 1.57(D1 + D2) + (D2 - D1)^2 / 4CThe general case for most two-pulley drivesThree or more pulleys, idlersApproximation onlyWrap angles change the picture; ask us to calculate from the full layoutWorked example: an HTD 8M drive with two 20-tooth pulleys (160 mm pitch diameter) and a 500 mm center distance gives L = 2 x 500 + 3.14 x 160 = 1502.4 mm. The nearest whole-tooth 8M belt is 1504 mm (188 teeth), about 1.6 mm longer than calculated, which the center distance adjustment or a tensioner absorbs.Pulley geometry is the input: pitch diameter and tooth count decide the belt before any tape measure comes out.From calculated length to a real beltRound to whole teeth: the final belt length is always the tooth count times the pitch.Check center distance adjustment: the drive needs extra travel to fit the belt and to set tension, commonly a few millimetres each way depending on size.Use pitch diameter, not outside diameter: the outside diameter is larger by roughly twice the tooth depth, and mixing them up shifts the result by several teeth.For drives with three or more pulleys or small wrap angles, let us calculate the exact length from your layout sketch, because the simple formula drifts as angles change. The formula gives a theoretical length. Real belts carry pitch-length tolerances, and the drive has to tolerate the rounding. When in doubt, send the pulley tooth counts and the center distance and we will verify the belt length before quoting.Center distance and tension are checked on the machine after the calculated length is chosen.A correctly calculated length runs with even tooth engagement and steady tracking.Want us to verify your belt length?Send the pulley tooth counts, diameters and center distance, or a photo of the drive. We will confirm the pitch, length and width and quote the belt.Verify My Belt Length

Question 9

Use idlers to add wrap on the small pulley, stabilize long slack spans, route around obstacles or provide tension with a fixed center distance. Place idlers on the slack side; back-side flat idlers must respect the minimum back-bend diameter for the cord type.

Accepted Answer

Short answer: use idlers when you need more teeth on the small pulley, need to control belt slack-side behavior, or cannot reach the desired center distance. Put inside idlers on the slack side touching the back or the teeth, and outside (back-side) idlers on the slack side too — as a rule, avoid placing any idler on the tight side, because pressing the tight side raises tension and shortens belt life. Flat idlers touching the belt back should match the cord's flexibility requirements in diameter.When an idler actually helpsMore wrap on the small pulleyAn inside idler opposite the small pulley increases wrapped teeth, raising capacity without changing pitch or width.Controlling slack sideA back-side idler on the slack side damps whip and flutter on long spans, keeping tooth engagement clean.Routing around obstaclesIdlers let the belt dodge machine structure when the straight line between pulleys is blocked.Manual tension adjustmentA spring-loaded or adjustable idler provides tensioning where the center distance is fixed and cannot move.Back-side idlers work on the slack side to stabilize long spans.Idler placement rulesIdler typeWhere to placeNotesInside (toothed) idlerSlack side, pushing outward opposite the small pulleyUse a pulley with teeth; observe minimum diameter for the pitchOutside (flat) idlerSlack side, pressing the belt backWide flat face, crowned or plain; respect minimum back-bend diameter for the cord typeTensioner idlerSlack side, on an adjustable or spring-loaded mountTravel must cover tension build and belt wear compensationWorking with fixed center distanceCalculate the required belt pitch length from the pulley teeth, pitch and center distance; choose the nearest available belt length.If the nearest length is shorter, use an adjustable idler to take up the difference — this is a standard, accepted practice.If it is longer, check whether a one- or two-tooth-smaller pulley pair restores the fit before changing the machine layout.After installation, re-check tension after run-in; a fixed center distance has no self-compensation.Good idler layout adds capacity and stability without redesigning the drive. Minimum idler diameters and tooth-count limits are profile- and cord-specific — an idler that is too small back-bends the cords and causes early cord fatigue. Values differ by manufacturer; confirm the limits for your profile before finalizing the layout.A spring-loaded idler keeps tension stable as the belt wears in.Checking your drive layout?Send a sketch or photo of your drive with pulley teeth, pitch and center distance — we will review the idler arrangement, check diameters against the cord limits, and propose the right belt length.Have Our Engineers Review It

Question 10

Select a timing belt in order: service factor, design power, tooth profile and pitch from the rating table at your RPM, pulley sizes respecting minimum teeth, then width from the per-unit-width rating. Matching the profile to torque and speed prevents early failure.

Accepted Answer

Short answer: select a timing belt in this order: (1) service factor from your machine type, (2) design power = motor power × service factor, (3) pick a tooth profile and pitch so the belt's power rating covers design power at your RPM, (4) choose pulley sizes that respect minimum teeth and a sane center distance, (5) size the width from the per-unit-width rating. A quick sanity check: small pulleys and high RPM stress teeth — larger pitch or wider belts relieve them.Selection steps in practice1. Gather drive dataMotor power, RPM (driver and driven), target ratio, center distance or available space, daily running hours and load nature (steady, shock, reversing).2. Apply the service factorMultiply rated power by the service factor for your machine class (light duty machines lower, crushers and compressors higher). This gives design power.3. Choose profile and pitchUse the manufacturer's rating table at your small-pulley RPM. Higher speed with small torque favors fine pitch (T/AT, HTD 3M/5M); high torque at low speed favors larger pitch (HTD 8M/14M, RPP).4. Fix pulleys and center distanceRespect the minimum recommended teeth for the profile, keep center distance near (1 to 1.5) × the sum of pulley radii as a starting point, then verify belt length options.A structured selection prevents undersized belts and premature failure.Quick rules of thumbSituationLean towardHigh speed, low torque (spindles, fans)Fine pitch profiles (T2.5/T5, HTD 3M/5M)High torque, low speed (heavy conveyors, mixers)Large pitch (HTD 8M/14M, RPP8)Shock or reversing loadsAramid or fiberglass cords; avoid very small pulleysCompact design neededNarrower high-rated profiles; check minimum teeth limitsOily or hot environmentMatching compound (PU or HNBR-based constructions)Common selection mistakesSizing from installed motor power without a service factor — start-up and shock loads then eat the belt.Using fewer teeth on the small pulley than the profile's minimum — tooth jump and cord stress follow.Ignoring belt width correction: ratings are usually given per unit width, so width is the last lever, not the first.Forgetting tensioning provision — a fixed center distance with no tensioner invites ratcheting after run-in.Copying a competitor's part number without checking profile compatibility (HTD vs STD vs T/AT are not interchangeable).Pulley diameter, pitch and width together decide the real capacity of the drive. The steps above are the general industry method; exact service factors, rating tables and minimum-teeth values differ by manufacturer and profile. Send us your motor power, RPM, ratio and center distance — we will run the selection and propose a belt and pulley combination with the rating breakdown.Profile choice balances torque, speed, noise and available space.Want us to size it for you?Email your drive data (power, RPM, ratio, center distance, environment) and we will return a belt selection with profile, width, pulley teeth and tension recommendation — usually within one working day.Request Belt Selection

Question 11

Set timing belt tension to the manufacturer's table value for your belt width and span, measured with a frequency meter or deflection gauge — not by feel. Too loose jumps teeth; too tight kills cords and bearings. Re-check after run-in.

Accepted Answer

Short answer: set timing belt tension so the belt neither ratchets (jumps teeth) under peak load nor exceeds the cord's safe stretch limit. In practice this means following the manufacturer's tension-force table for your belt width and span — measured with a frequency meter or spring-scale deflection method, not by feel. A common starting point for many industrial synchronous drives is a deflection force that produces roughly 1.6% elongation on the slack side at recommended pretension, but the correct value always depends on the specific belt and drive data.How to check tension in 4 steps1. Get the baselineUse the belt maker's tension table: it lists target span frequency (Hz) or deflection force (N) by belt section, width and center distance.2. Measure, do not guessPluck the belt and read the span frequency with a meter, or press at mid-span with a spring scale and measure deflection. Thumb-pressure methods routinely over-tension.3. Adjust with the tensioner or center distanceIncrease tension gradually and re-measure after each adjustment. Lock the adjustment and re-check after a short run-in period.4. Re-check after run-inNew belts seat into the pulley grooves and can lose a little tension. Re-measure after the first hours of operation and again periodically.A frequency meter converts span vibration into a tension reading in seconds.Symptoms of wrong tensionSymptomLikely causeFixTeeth jumping / ratcheting under loadUnder-tensionIncrease tension to table value; verify pulley alignment tooCord breakage, tooth root cracksOver-tensionReduce to spec; check bearing loadsNoisy, whining driveUsually over-tension (sometimes misalignment)Re-measure and adjust; check alignmentUneven wear on one belt edgeMisalignment, not tensionLaser or straightedge alignment checkCommon mistakes to avoidTensioning by feel or by "as tight as possible" — this overloads cords and bearings and shortens belt life.Ignoring span length: a longer span needs different target values than a short one at the same belt.Reusing a failed belt's tension setting without reviewing the root cause of the failure.Skipping the run-in re-check — most tension loss happens in the first hours of operation. Tension values are specific to each belt section, width and cord construction. The figures above are industry-general guidance; always use the tension table supplied with your belt or ask us for the exact values for your part number. If your drive keeps losing tension, the cause may be pulley wear, wrong center distance or an undersized belt rather than the tensioner.Correct tension protects cords, teeth and bearings at the same time.Tension is re-measured after every adjustment and again after run-in.Need the exact tension spec?Send us your belt part number or drive details (motor power, RPM, pulley diameters, center distance) and we will return the target tension values and installation notes.Request Tension Specs

Question 12

Recurring timing belt failures trace back to five root causes: under-sizing, incorrect tension, misalignment, pulleys below minimum diameter, or harsh environment. Fix the cause before replacing the belt — a diagnosis table and five pre-installation checks.

Accepted Answer

Short answer: recurring belt failures almost always trace back to one of five root causes: under-sizing the belt for the real torque, incorrect tension (too loose causes tooth jumping, too tight cord fatigue), misalignment, small pulley diameters below the profile limit, or harsh environment (heat, oil, debris). Replacing the belt without fixing the cause guarantees the next failure — diagnose the drive first.Common failure modes and what causes themSymptomMost likely causeFixTeeth shear off at the rootUnder-sized width, torque spikes, small pulley with too few teethRe-size width, check service factor, enlarge small pulleyBelt jumps teeth (ratcheting)Too little tension, overload, debris in the teethRe-tension, add a tensioner if needed, add guardingCord breakage, belt snapsExcessive tension, shock loads, cord damaged at installationCorrect tension, soften starts, use aramid cord for impactTooth cracking, chunkingHeat aging, oil/chemical attack, pulleys below minimum diameterCheck temperature and media, meet minimum pulley specsEdge wear on one sidePulley or shaft misalignment, frame flexRe-align pulleys, stiffen the mountingNoise and rapid wear on both flanksWrong tension or mismatched profile/pitchVerify profile, pitch and tension procedureRead the failure pattern on the belt — it points to the root cause.Five checks before you install the next belt1. Re-check sizingConfirm the belt width against actual motor power, RPM and the true load profile — not nameplate assumptions. Repeated tooth shear means the sizing, not the belt.2. Verify tensionMeasure with a tension gauge or frequency meter instead of feel. Loose belts jump teeth; over-tight belts kill cords and bearings.3. Check alignmentUse a straightedge or laser tool across both pulleys. A few tenths of a degree of skew is enough to wear one edge away.4. Inspect pulleysWorn tooth flanges, dents and debris re-destroy a new belt within days. Minimum pulley diameters protect cord life.5. Audit the environmentHeat, oil mist, dust and chemicals each shorten belt life differently — the compound and cover must match the exposure.Compound, cord and construction can all be matched to the failure mode.When a standard belt is not enoughFrequent shock starts: aramid-cord construction absorbs impact far better than glass-fiber cord.Hot or oily surroundings: HNBR or other resistant compounds and special covers extend service life.Non-standard length or width: a correct-fit custom belt removes the shortcuts that cause repeated failure. If a belt fails again within weeks, send us photos of the failed belt and the drive details (motor power, RPM, pulley sizes, tension setting). GOODLY engineers review the failure mode and recommend the construction change — a cross-reference swap alone does not fix a drive problem.Comparing the failed belt with the correct construction speeds up the fix.Belt keeps failing? Send us the evidenceEmail photos of the failed belt plus your drive data — we will identify the root cause, recommend the right construction and quote a lasting fix.Request a Failure Analysis

Question 13

Size the width from design power (transmitted power × service factor) divided by the per-width belt rating at your speed, then round up to a standard width. Motor power, RPM, pulley sizes and load type are the inputs needed.

Accepted Answer

Short answer: width is sized from the torque (or power) the belt must transmit and the speed of the drive. Start from the design power (transmitted power × service factor), read the belt rating per unit width for your pitch and speed, then divide to get the minimum width — and round up to the nearest standard width. When in doubt between two widths, choose the wider one.The sizing logic in four steps1. Design powerMultiply the transmitted power by a service factor (commonly about 1.1–1.6 depending on load type, starting frequency and duty hours).2. Belt speedBelt speed = pitch diameter × RPM. Higher speed usually means higher per-width capacity, but check the pitch limit for your profile.3. Per-width ratingManufacturer tables give torque or power per 10 mm (or per inch) of width for each pitch and speed. Interpolate if your speed falls between rows.4. Round upRequired width = design power ÷ per-width rating. Round up to a standard stock width rather than rounding down.Belt width is sized from design power and the per-width rating.Practical rules of thumbHigher shock loads or frequent starts → apply a larger service factor rather than guessing.Small pulley diameter reduces tooth engagement — if the small pulley has fewer teeth than recommended for the pitch, step up one width class.Idlers on the back or inside of the belt add bending stress; allow extra width margin when they are present.For conveyor or positioning duty with constant load, width can often stay at the minimum rating; for reciprocating loads, add margin.What data we need from youParameterWhy it mattersMotor power and RPMDetermines torque and belt speedPitch and tooth profileMust match existing or new pulleysPulley teeth / diametersAffects tooth engagement and capacityCenter distanceDetermines belt lengthLoad type and duty hoursSets the service factorStandard widths cover most drives; non-standard widths are made to order.Check pitch, width and length against your drive data before ordering. Undersized belts wear teeth and jump; oversized belts raise bearing loads and cost. A short check of the drive data usually pays for itself. Values above are industry-general guidance — final sizing depends on your actual drive.Send us your drive dataShare motor power, RPM, pulley sizes and load type — we will size the pitch and width for you and quote standard or custom belts.Request Sizing Help

Question 14

Match the tooth profile to your pulleys first: HTD suits higher torque general drives, STD/RPP suits precision, T/AT suits European machinery and classical trapezoidal profiles suit legacy equipment. Then confirm pitch, length and width.

Accepted Answer

Short answer: match the tooth profile to your drive first, then confirm pitch, width and belt length. HTD (curvilinear) suits higher torque and quieter runs, STPD/AT profiles suit precision positioning, and classical trapezoidal (T/AT, MXL–XL–L) profiles are common in legacy equipment. Always cross-check the pitch against your existing pulleys before ordering.Tooth profile: match the pulleys, not the catalogThe profile must mate exactly with your pulley. If you keep the existing pulleys, identify the pitch (for example 5 mm, 8 mm, or 1/2 inch) and the profile family marked on the old belt. If you are free to choose pulleys, select the profile from the torque and speed requirements of the drive.Profile familyTypical useNotesHTD (3M/5M/8M/14M)General power transmission, higher torqueCurvilinear teeth, smoother mesh, less vibrationSTD / RPP (8M, 14M)Higher precision and load sharingRound-profile variants designed for reduced backlashT / AT (T5, T10, AT5, AT10)European machinery, positioning drivesAT profiles carry more load than T profiles at the same pitchClassical inch (MXL, XL, L, H)Legacy US equipmentTrapezoidal teeth; widely used in older machinesTooth profile and pitch decide whether the belt seats correctly on your pulley.Three checks before you order1. Pitch and profileMeasure or read the pitch of the pulley and confirm the profile family. A wrong pitch will not seat, and a wrong profile will wear quickly.2. Belt lengthUse the pitch length marked on the old belt, or calculate from center distance and pulley diameters. Tolerance is normally a few millimeters.3. Width by loadWider belts carry more torque. Size the width from the drive power, speed, and service factor, with a reasonable safety margin.Material and cord optionsBody: neoprene rubber or PU; rubber suits most industrial drives, PU suits clean, oily or hygienic environments.Tension cord: glass fiber for standard use, aramid (Kevlar-type) for shock loads and low stretch, steel for high-load PU belts.Cover: nylon fabric reduces friction noise; special covers improve oil or heat resistance in harsh conditions.Trapezoidal and curvilinear profiles serve different drive designs.Compare pitch, tooth shape and width before choosing the profile. If you are replacing a belt from another brand, the profile and pitch are what matter for compatibility — the brand name does not. GOODLY Belts is an independent manufacturer and offers cross-reference sizing for common international profiles.Not sure which profile fits your machine?Send us your old belt dimensions or machine data — our engineers will confirm the profile, pitch and width within one working day.Ask an Engineer

Question 15

Different belt materials are suitable for different industries. GOODLY helps customers choose the right material according to application, temperature, load, hygiene, and wear-resistance requirements.

Accepted Answer

PU, PVC, rubber, and silicone belts are commonly used in industrial production, but they are suitable for different working environments.PU belts are widely used in food processing, packaging, electronics, automation, and light conveying applications. They offer good wear resistance, clean surface, and stable performance.PVC belts are often used for general conveying applications. They are cost-effective and suitable for many light to medium-duty production lines.Rubber belts are suitable for heavy-load, high-friction, and wear-resistant applications. They are commonly used in industrial equipment, logistics, agriculture, mining, and heavy-duty conveying systems.Silicone belts are often used for heat-resistant, non-stick, or special surface applications. They are suitable for industries such as food, hygiene products, packaging, and high-temperature conveying.If you are not sure which material is better, GOODLY can recommend the right belt material based on your products, machine conditions, and production environment.

Question 16

Not sure which timing belt fits your machine? GOODLY helps customers select the right industrial belt based on machine type, application, size, material, and working conditions.

Accepted Answer

Choosing the right industrial belt depends on several important factors: machine type, belt size, running speed, load, temperature, surface requirement, and the product being conveyed or driven.For example, packaging machines may need high grip timing belts or PU conveyor belts. Food processing equipment often requires food-grade PU or silicone belts. Heavy-duty conveying systems may need reinforced rubber belts or nylon flat belts.If you are not sure which belt you need, you can send us your belt photo, machine model, old belt size, drawing, or working video. Our team will help you identify the belt type and recommend a suitable solution.At GOODLY, we do not only sell standard belts. We help factory customers reduce wrong purchases, shorten replacement time, and find belts that match real production needs.

Belt Selection

Are you looking for a reliable manufacturer of conveyor belt products?

products

Support

Company