Trapezoidal Timing Belts (MXL, XL, L, H, XH, XXH)

Trapezoidal timing belts are the classical inch-pitch synchronous belts – straight-flanked, trapezoid-shaped teeth in six standard pitches from MXL (0.080 in) to XXH (1-1/4 in). Texas Belting stocks 22,000+ trapezoidal belts in Houston, TX from Gates, Continental, Megadyne and our D&D Global and Diesel Belting lines.

Shop trapezoidal belts by pitch

On this page: Pitch dimensions · Read a part number · Which pitch do I have? · Trapezoidal vs HTD and GT · Houston supplier · Common mistakes · FAQ

Trapezoidal pitch dimensions

Pitch is the tooth-to-tooth spacing, and it is the one spec that can never be substituted – each of the six trapezoidal pitches meshes only with sprockets cut for that pitch. The six sizes step up roughly in load capacity: MXL and XL serve instruments and light office-machine drives, L and H cover most fractional and integral horsepower industrial drives, and XH and XXH handle heavy, slow, high-torque machinery.

Pitches are industry-standard nominal dimensions. For tooth heights and full engineering data, see our timing belt pitch chart.

How to read a trapezoidal part number

Trapezoidal part numbers read pitch length, then pitch code, then width – and both numbers use fixed decimal conventions. The leading number is the pitch length in tenths of an inch, and the trailing number is the belt width in hundredths of an inch. So 480H300 is a 48.0 in pitch length, H pitch (1/2 in), 3.00 in wide belt.

• Length check: pitch length divided by pitch equals the tooth count. 480H300: 48.0 / 0.5 = 96 teeth. If that division does not come out to a whole number, the part number is wrong.
• Width suffixes: 025 = 1/4 in, 037 = 3/8 in, 050 = 1/2 in, 075 = 3/4 in, 100 = 1 in, 150 = 1-1/2 in, 200 = 2 in, 300 = 3 in, 400 = 4 in, 500 = 5 in.
• Same rule at every size: 112MXL025 is 11.2 in long and 1/4 in wide; 1200XXH300 is 120.0 in long and 3 in wide.

If the old belt's printing is worn away, count the teeth and multiply by the pitch to recover the length, then match the width to the sprocket face. Our timing belt measuring guide walks through it step by step.

Which trapezoidal pitch do I have?

Measure center-to-center between two adjacent teeth. About 2 mm (0.080 in) is MXL, 1/5 in is XL, 3/8 in is L, 1/2 in is H, 7/8 in is XH, and 1-1/4 in is XXH. On a worn belt, measure the span of ten pitches – first tooth center to the eleventh – and divide by ten; the average cancels out local wear. Then verify against the sprocket: trapezoidal sprocket grooves have flat, straight flanks, unlike the rounded pockets of HTD and GT sprockets.

Width matters just as much for capacity. Trapezoidal belts of one pitch share the same tooth form at every width, so a wider belt is the standard fix for a drive that keeps shearing teeth – provided the sprocket face can carry it. Going up in width does not change the part number's length section: a 390L075 and 390L100 fit the same sprockets if the face width allows.

Trapezoidal vs HTD and GT: should you convert?

Trapezoidal belts are the oldest synchronous profile, and curvilinear designs carry more load in the same width – that is why HTD and GT dominate new industrial drives. But trapezoidal belts are not obsolete: they remain the correct replacement for the enormous base of legacy US machinery, and MXL and XL are still specified for light positioning drives where their small pitch gives fine resolution.

Converting a trapezoidal drive to HTD or GT means replacing the sprockets as well as the belt – the tooth forms do not intermesh at all, in either direction. That is usually only worth doing when a drive repeatedly strips teeth at its maximum practical width, or when the belt size is becoming hard to source. If you are weighing a conversion, send us the drive details and we will quote belt and sprockets as a package.

Trapezoidal timing belt supplier in Houston, TX

Texas Belting & Supply stocks its trapezoidal inventory – MXL through XXH – in Houston, and most stocked sizes ship same day. We supply maintenance crews, machine shops and OEMs across the Texas Gulf Coast and ship nationwide. For odd widths, discontinued sizes or full drive packages, call (888) 203-2358 to confirm availability.

Common trapezoidal belt selection mistakes

• Confusing XL and L. The names read like sizes of the same belt, but they are different pitches (1/5 in vs 3/8 in) that never interchange. Read the code, not the letters' apparent meaning.
• Ordering MXL for a 40DP drive. The 0.0016 in pitch difference binds long belts. Check the sprocket spec.
• Treating the width number as inches. The trailing number is hundredths: 300 means 3.00 in, not 300 of anything metric.
• Replacing the belt on hooked sprockets. Worn trapezoidal sprocket teeth develop a hooked flank that shears new belts within weeks. Inspect at every change.
• Assuming a close metric pitch will run. T10 (10 mm) is not H (12.7 mm), and 8M is not L. Close is not compatible on toothed drives.
• Cranking tension past spec to stop tooth jump. Check installation tension first – a loose belt is the most common cause of ratcheting, and tensioning to spec is the fix. If a properly tensioned belt still jumps, the drive is undersized or the sprockets are worn; more tension beyond spec just adds bearing load.

When to call instead of browse

• The belt is shredded and unreadable – sprocket tooth counts and shaft centers are enough for us to size it.
• You need a width or length outside the standard range, or a discontinued size cross-referenced.
• You are converting a trapezoidal drive to HTD or GT and want belt plus sprockets quoted together.

Call (888) 203-2358 or send us what you have – a photo and two measurements usually settle it.

Frequently asked questions

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Last updated: July 2026