Buying guide
MXL, XL, L, T2.5, T5 and T10 Timing Belts Explained
Trapezoidal-tooth belts in inch and metric pitches: how to identify them and why they do not mix.
Before round-tooth profiles like HTD and GT2, most timing belts had straight-sided trapezoidal teeth. They are still used in many machines and replacement parts. There are two families: inch pitch (MXL, XL, L) and metric pitch (T2.5, T5, T10).
Pitch table
| Profile | Pitch | Family |
|---|---|---|
| MXL | 0.080 in (2.032 mm) | Inch |
| XL | 0.200 in (5.08 mm) | Inch |
| L | 0.375 in (9.525 mm) | Inch |
| T2.5 | 2.5 mm | Metric |
| T5 | 5 mm | Metric |
| T10 | 10 mm | Metric |
Do not mix them
- MXL is not GT2. 2.032 mm and 2 mm look close, but the tooth shapes differ and the error adds up over every tooth.
- XL is not T5 and not HTD 5M. Similar pitch, different tooth form.
- Always replace a belt with the same profile as the pulleys, or change belt and pulleys together.
How to identify an old belt
- Look for printed markings such as 130XL, 200MXL or T5-500.
- If unreadable, measure across 10 teeth and divide by 10 to get the pitch.
- Check the tooth shape: straight-sided (trapezoidal) or rounded (HTD, GT2).
Shop: MXL pulleys · XL pulleys · T2.5 pulleys
See also: GT2 vs GT3 vs HTD · HTD 3M vs 5M vs 8M · choosing a pulley
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