Can you reverse-engineer a timing belt from a worn sample or photos?

Question

Accepted Answer

Short answer: yes — a worn sample is often the fastest way to order a replacement timing belt. Send the old belt (even broken or heavily worn) and we measure pitch length, tooth profile, pitch, width, cord visibility and compound to build a dimensioned drawing for your approval before production. Clear photos with a ruler can be enough for a first feasibility check and quote, but a physical sample (or the original part number) is needed to confirm the exact profile and cord before manufacturing.

What we measure from your sample

Pitch and tooth profile

Tooth pitch and shape (HTD, STD, T, AT, RPP or imperial) identify the profile family — this decides which pulleys it will mesh with.

Length and tooth count

Total pitch length and number of teeth are measured and cross-checked against each other, since one confirms the other.

Width and thickness

Belt width and body thickness, including any covering fabric or coating on teeth or back.

Cord and compound

Visible cords and rubber or PU body guide material selection; application data helps confirm the choice for your duty.

Worn timing belt sample on a measuring bench — Even a broken or heavily worn sample carries all the dimensional data needed.

How to send photos that are good enough for a quote

Lay the belt flat and straight; photograph the full length plus a close-up of the teeth with a ruler or tape in frame.
Provide the tooth count and, ideally, the pitch length measured along the pitch line; if unsure, measure outside circumference and tell us it is outside.
Shoot the width end-on and note any markings or numbers printed on the belt — original part numbers speed everything up.
Mention the machine and application so the cord and compound can be matched, not just the dimensions.

Sample vs photo vs part number

You send	What we can do
Original part number	Fastest cross-reference quote if the construction is known
Physical sample	Full measurement, profile confirmation and approval drawing — best accuracy
Photos with ruler	Preliminary quote and feasibility; final confirmation by sample or part number
Machine data only	Selection proposal from drive parameters (power, RPM, pulleys)

Reverse engineering is provided for dimensional compatibility. Brand names that appear on samples (Gates, Continental, Bando, Mitsuboshi and similar) are used only as cross-references; GOODLY is an independent manufacturer and not affiliated with them, and we do not copy proprietary constructions beyond dimensional compatibility.

Pitch, tooth shape and width are recorded on an approval drawing before production.

New replacement belt finished next to the customer sample — The replacement is approved against the sample dimensions before it ships.

Have a worn belt to replace?

Ship the sample or send sharp photos with a ruler plus the machine type — we will return a measurement confirmation, approval drawing and quotation.

Start from My Sample