Short answer: the roll price is the cost line that is easiest to compare and the least likely to decide the outcome. Application time, rework, over-specification, waste and changeover usually move more money — and all five can be measured on your own line in a week, which makes the comparison yours rather than the supplier's.
This guide is about what to measure. It deliberately contains no savings percentages: a figure from somebody else's line tells you nothing about yours, and any supplier quoting one should be asked where it came from.
1. Material cost per harness, not per roll
Convert every quote to the same unit before comparing. A roll of a thinner tape contains more usable length; a wider tape may cover a bundle in fewer turns; a grade that holds an overlap at 50% may need less length than one applied at 65%.
Collect: tape length consumed per harness (measure, do not estimate), roll length and price, and the overlap percentage the work instruction specifies.
2. Application time
On manual lines this is often the largest difference between two candidates, and it is invisible in a quotation. What changes it:
- Hand tear vs blade. Every cut that needs scissors adds handling time and a cut-through risk to the cable below.
- Unwind force. Too tight slows the operator; too loose makes the roll telescope and wander.
- Conformability. A stiff backing takes more turns and more attention at branch points.
- Roll changes. Shorter rolls mean more interruptions per shift.
Measure it properly: time ten harnesses per candidate, same operator, same fixture, after a short familiarisation. The spread between candidates is usually larger than anyone expects.
3. Rework — the cost line nobody budgets
Rework is where a cheap tape becomes expensive. The failure modes worth counting separately:
| Failure | Where it shows up | What to record |
|---|---|---|
| Flagging at the tape end | After thermal cycling or transport | Units affected per 100, and at which zone |
| Edge lift at a branch | Final inspection or at the customer | Position on the harness, bundle diameter |
| Adhesive residue | Rework and repair operations | Cleaning time added per unit |
| Noise complaint | Vehicle assembly, often much later | Zone, and whether a damping grade was specified |
A rework rate measured over a representative run — not a single shift — is the only number that makes a price difference meaningful.
4. Over-specification: paying for performance you do not use
The most common structural waste in harness tape is buying one grade for the whole loom because a short section runs hot. The cabin then carries a stiffer, costlier tape, wraps more slowly, and damps noise less well than a fleece would.
Zoning the harness is usually cheaper and faster:
- cabin and trim-side sections — a soft fleece grade for noise;
- general bundling — a hand-tearable cloth grade;
- engine-bay and high-abrasion runs — a woven PET grade at the abrasion class the drawing names;
- against hot components — a glass-cloth or high-temperature grade only where it is needed.
The trade-off is more part numbers to manage. Count the sections before deciding: on a long harness, zoning usually wins; on a short one it may not.
5. Waste and changeover
- Roll ends. Unusable tail length multiplied by rolls per year is real money, and it depends on roll length versus the length consumed per harness.
- Width mismatch. Using a 25 mm tape where 19 mm is specified wastes material on every turn.
- Qualification cost. Changing an approved grade on an automotive programme means samples, testing, paperwork and sometimes customer approval. Count it once, but count it.
- Stock obsolescence. A grade dropped from the drawing leaves inventory behind. Order against the programme, not against the discount.
6. A one-week measurement plan
- Day 1: record tape length consumed per harness and the current roll price; convert to cost per harness.
- Day 2: time ten harnesses with the incumbent tape; note roll changes and any cuts needing a blade.
- Day 3–4: repeat with the candidate grade after a familiarisation run.
- Day 5: pull the rework records for the last representative period and classify them by failure mode and zone.
- Day 5: list the zones on the harness and check whether one grade is carrying requirements only one zone needs.
With those five numbers a price comparison becomes a cost comparison — and the decision stops depending on whose brochure is more confident.
FAQ
How much of the cost is the roll price?
On a manual line, usually a minority. Application time, rework, waste and over-specification often move more.
What is over-specification?
Buying one high-spec grade for a whole harness because one section needs it. Zoning is normally cheaper and faster.
Does hand-tearable tape save time?
It removes the blade from the operation. Whether that matters depends on cuts per harness — count them, then time ten units.
What belongs in a cost comparison?
Cost per harness, application time, measured rework rate, waste including roll ends, and qualification cost.
Related: total cost of ownership, harness tape types and how to choose, hand-tearable cloth tape, and the selection guide.