Most fleets answer "what does a tyre cost?" with the invoice price. That number is real, but it is
not a cost — it is a purchase. The cost only exists once you divide it by what the tyre actually
delivered, and that is where the numbers get uncomfortable.
This article gives you the arithmetic. The inputs are yours; the structure is the part worth
borrowing.
The wrong denominator
Comparing tyres by purchase price assumes every tyre delivers the same hours. On a mine site that
assumption fails constantly: one tyre completes its planned life, the next is pulled at 60% because
it ran soft, a third is destroyed by a cut. All three were invoiced for the same amount. Only one
of them earned it back.
So the denominator has to be hours delivered, not tyres bought:
> Cost per machine-hour = (tyres consumed in the period) ÷ (machine-hours in the period)
Everything below is an attempt to make the numerator honest.
The five components
Split the numerator into five lines, because they are managed by different people and only two of
them respond to monitoring:
1. Planned consumption. Tyres that reach their planned hours. This is a scheduling and rotation
question; monitoring does not reduce it, and no vendor should claim it does.
2. Premature removal for wear. Tyres pulled early because of irregular wear, misalignment,
mismatched duals. Partly preventable — monitoring catches the pressure and temperature
conditions that cause it.
3. Failure events. Cuts, impacts, sidewall damage. Monitoring does not prevent the impact, but
it changes the consequence when the operator is warned in time to stop.
4. Labour for inspection. Walk-arounds, gauge checks, depot inspections. This is the line that
most often pays for a monitoring system on its own, because it is a recurring cost that
disappears when the data arrives by itself.
5. Downtime. The hours the machine did not work because of a tyre event. This is usually the
biggest line and the one finance never attributes to tyres.
A worked structure (with illustrative numbers)
The numbers below are illustrative, not market prices — substitute your own. What matters is
the shape of the result.
Assume one haul truck, one billing period:
| Line | Illustrative figure | Note |
|---|---|---|
| Machine-hours worked | 500 h | From your hour meter |
| Tyres consumed | 4 | Purchase or amortise |
| Average purchase price | *your number* | Put the invoice value here |
| Tyres removed early | 2 of 4 | The line to watch |
| Hours lost to tyre events | 12 h | Downtime, from the shift report |
| Inspection labour | 30 h | Walk-arounds and gauges |
Now express the outcome two ways. First, tyres per machine-hour: 4 ÷ 500 = 0.008 tyres/h.
Second, the share of consumption that was not planned: 2 ÷ 4 = 50%.
That second number is the one to manage. A fleet that halves premature removals has, in this
illustration, removed a quarter of its tyre consumption without negotiating a single price.
Which lever actually dominates
Before buying anything, rank the five lines for your site. In most hauls the ranking looks like
this, and it is rarely the ranking people expect:
- Downtime usually dominates, and is invisible in the tyre budget because it is booked against
the machine.
- Premature removal is second, and it is the one monitoring addresses most directly.
- Inspection labour is third, and it is the cleanest to demonstrate — hours removed from the
schedule.
- Planned consumption and failure events are the smallest *controllable* lines.
If your ranking puts purchase price first, you are comparing invoices, not costs.
What monitoring changes, and what it does not
A pressure and temperature system does five things worth paying for:
- It tells you a tyre is going down while the machine is still moving, not at the next
walk-around.
- It catches temperature anomalies, which often precede a bearing or brake failure that costs
far more than the tyre.
- It makes the pressure history auditable, so a wear claim against a supplier or a driver
behaviour dispute has data behind it.
- It removes part of the inspection labour line.
- It shortens the time to decision, which is the only way downtime is actually reduced.
It does not fix alignment, driver behaviour or road maintenance, and no honest supplier should
tell you otherwise. On a site where tyres fail mainly from cuts, a monitoring system will not move
the number much — and that is worth knowing before the purchase order, not after.
How to run the trial without fooling yourself
- Pick a control group. Same haul cycle, same shift pattern, no monitoring. Without this the
result is an anecdote.
- Record the same five lines for both groups, for one full billing period.
- Pre-commit to the metric. Cost per machine-hour, and the rate of premature removals. Write
both down before the trial starts.
- Do not change two things at once. If you also change the rotation schedule mid-trial, you have
measured nothing.
- One tyre life is the honest horizon. A first directional read after one period is legitimate;
a claim of payback in three weeks is not.
- Write down the baseline before anything is installed. The most common way a fleet loses money
on monitoring is not a bad product: it is starting without a baseline, so nobody can tell whether
anything improved six months later. Two numbers are enough — premature removals per hundred
machine-hours, and inspection hours per machine per week. Both come out of records the site
already keeps.
Where to go next
The specification side of this — accuracy, interval, wheel count — is on
the pressure accuracy page. The machine class and typical
configuration are on the mining TPMS page and
the mining truck installation page.
If you want to run this model on your own fleet, send the five lines with your numbers and we will
do the arithmetic in writing — including the case where the answer is "not worth it".
FAQ
- Is a TPMS worth it on a mining fleet?
- Only measurable against a baseline. Run a control group on the same haul cycle, record the same events for one billing period, then compare cost per machine-hour — not purchase price.
- What is the largest cost component in OTR tyre TCO?
- Usually premature removal: a tyre scrapped before its planned hours carries the whole purchase price against a fraction of the life. That is where early detection pays.
- Do I need pressure and temperature, or just pressure?
- Both. Temperature often reveals a dragging brake or a failing bearing before pressure changes, and those failures cost more than a soft tyre.
- How long before a trial shows a result?
- One full tyre life cycle is the honest answer. For a first directional read, one billing period with a matched control group is enough to see whether the rate of premature removals moves.