Cost per hour is the honest measure of undercarriage expense: total parts cost, labour, and downtime divided by the operating hours the parts delivered. The metric turns the undercarriage from a cost surprise into a budget line, and it makes the OEM-versus-aftermarket and rebuild-versus-replace decisions comparable. For an Ontario fleet, the cost-per-hour number is the one that justifies the maintenance plan.
Related reading: for the OEM comparison, see our OEM vs aftermarket guide, and for fleet budgeting, see our fleet maintenance guide.
Why Cost per Hour Is the Right Metric for the Undercarriage
Undercarriage costs are spread over thousands of hours, so the sticker price of a part says little about its real cost. Cost per hour captures the part price, the life it delivered, and the downtime around it in one number.
The metric is comparable across machines and routes: an expensive part with a long life can beat a cheap part with a short one. The comparison is the point.
The metric also smooths the budget: a fleet that tracks cost per hour knows its undercarriage line per machine before the replacement season starts. The number turns the wear log from a repair record into a forecast.
How to Calculate Parts Cost per Hour on Your Machine
Calculate the parts cost per hour by dividing the parts cost by the operating hours the set delivered. The example below shows the calculation with representative figures — replace them with your machine's numbers.
| Line | Example value |
|---|---|
| Roller set cost | $2,400 CAD |
| Operating hours delivered | 2,000 hours |
| Parts cost per hour | $1.20 per hour |
| Labour and downtime | Add per change |
Factoring Downtime and Labour Into the Full Cost Calculation
The full cost per hour adds labour and downtime to the parts cost: the hours the machine is down, the labour to change the parts, and the lost production. The addition is what separates parts cost from total undercarriage cost.
For a machine that works every day, downtime is the largest line. A part that saves money but costs an extra day of production is rarely the cheaper buy.
The labour line follows the same rule: the hours to change the part, at the shop rate, belong in the calculation because the change is part of the cost of running the part.
The downtime line is the one most fleets estimate rather than measure, and the estimate should be reviewed against the actual change records.
Comparing OEM vs Aftermarket per Hour
The per-hour comparison is where the OEM-versus-aftermarket decision gets decided: divide each route's total cost by its expected life at the machine's duty. The route with the lower cost per hour is the better buy for that machine.
The comparison needs the expected life in writing, because the life assumption drives the result. A supplier that documents the life makes the per-hour math possible.
Using Data to Time Replacements
The cost-per-hour data times the replacements: when the trend shows a part family running past its economical life, the replacement is scheduled before the failure. The data turns the wear log into a budget.
The timing rule is simple: replace when the cost of running the part longer exceeds the cost of changing it early. The per-hour number is what makes that comparison concrete.
The data also sets the reorder trigger: when the cost-per-hour trend shows the part family moving past its economical life, the order goes in against the maintenance stop. The trigger is the same discipline as the wear threshold, measured in dollars instead of millimetres.
The timing data also feeds the annual budget: the forecast of part families due in the coming year becomes the undercarriage line, and the line is reviewed against the actual spend each quarter.
Benchmarking Across Your Fleet
Benchmark the cost per hour across the fleet to find the machines that run outside the normal range: the machine with double the undercarriage cost per hour is the machine with a site, operator, or alignment problem worth investigating.
The benchmark is the fleet's early warning. A machine that drifts from the fleet average is a machine with a story, and the story is usually in the readings.
The benchmark also sets the budget: the fleet's cost-per-hour distribution shows where the undercarriage money goes and which machines carry the outliers. The distribution is the fleet's undercarriage financial map.
The benchmark review belongs on the quarterly calendar, where the outliers are checked against the readings before the budget is set.
Conclusion
Cost per hour measures the real undercarriage expense: parts, labour, and downtime divided by the hours delivered. Calculate it per machine, compare routes on the same basis, and benchmark across the fleet — the number is what justifies the maintenance plan.
Key Takeaways for Canadian Operators
- Divide total parts cost by the hours delivered for the per-hour number.
- Add labour and downtime to get the full cost per hour.
- Compare OEM and aftermarket routes on the same per-hour basis.
- Benchmark machines against the fleet average to find the outliers.
Frequently Asked Questions
Why is cost per hour better than part price?
Part price ignores life and downtime. Cost per hour includes the price, the hours delivered, the labour, and the lost production, which is the number that actually matters.
How do I get the expected life for a part?
Ask the supplier to document the expected life at your duty in writing. The life assumption drives the per-hour comparison.
What if a machine's cost per hour is above the fleet average?
Investigate the site, the operator, and the alignment readings. The outlier machine is usually telling a story that the parts alone do not.