Fuel and maintenance together typically account for the largest share of a carrier's variable cost, and they are the two lines operators most often get wrong on an application. Fuel is understated because the surcharge is assumed to cover it. Maintenance is understated because last year happened to be quiet. An underwriter normalizes both, and the normalized version is what your coverage ratio gets computed on.
This matters more than it sounds. If you claim eight cents a mile of maintenance on a tractor with 700,000 miles and the desk substitutes a defensible number, your adjusted earnings drop and your coverage drops with them. The size of the truck you can finance is decided by that substitution, not by the number you typed. The way to control it is to bring numbers that survive the test.
Fuel: the number that moves with two variables you control
Fuel cost per mile is price per gallon divided by miles per gallon. You do not control the first, and you control the second more than most operators believe. The arithmetic is unforgiving in both directions, which makes it one of the highest-leverage lines in the operation.
The levers behind the gap are habits
Sustained speed, idle time, tire pressure and specification, weight, aerodynamic condition and route selection. None of them is a project. All of them are habits, which is why fleets that report fuel economy by driver consistently outperform fleets that do not, running identical equipment on identical lanes.
The surcharge does not make fuel neutral
Fuel surcharge is often treated as a pass-through that cancels fuel risk. It does not, for three reasons. It is usually indexed to a published average that lags actual price movement, so a fast run-up is absorbed by you for weeks. It is generally calculated on loaded miles, so it contributes nothing to your empty miles. And on spot freight it is frequently folded into an all-in rate, at which point the distinction disappears entirely.
The practical consequence is that fuel exposure is real even for a carrier that believes it has passed the cost through. When you model your cost per mile, model fuel at the price you actually pay across all miles, then treat surcharge revenue as revenue rather than as an offset. That framing produces a break-even you can trust.
Maintenance is a curve, not a line
New equipment under warranty produces low maintenance cost per mile, and operators who bought new frequently build their model on that period. It does not persist. Maintenance cost rises with mileage in steps rather than smoothly, because the expensive items arrive on their own schedules: tires, brakes, clutch, aftertreatment components, injectors, turbo, and eventually major engine work.
| Odometer band | Typical driver of cost | Illustrative maintenance reserve |
|---|---|---|
| Under 200,000 miles | Preventive service, mostly under warranty | $0.05 to $0.10 per mile |
| 200,000 to 450,000 | First tire and brake cycles, aftertreatment service | $0.10 to $0.16 per mile |
| 450,000 to 700,000 | Second cycles, injectors, turbo, cooling, driveline | $0.15 to $0.25 per mile |
| Above 700,000 | Major component and overhaul exposure | $0.20 to $0.35 per mile or more |
Treat those bands as a modeling aid. The point is not the specific cents. It is that a reserve set on the first band and never revisited will be wrong by a factor of two or three by the third, and the shortfall arrives as a single large repair rather than as a gradual squeeze.
How an underwriter tests your numbers
Three checks come up repeatedly, and all three are things you can run on yourself first.
Does claimed maintenance match fleet age
A very low maintenance figure on high-mileage equipment reads as either deferred maintenance or an incomplete accounting: repairs paid personally, or coded elsewhere. Both are adjusted. If your number is genuinely low because you do your own work, say so and show the parts spend, because your labor is a real cost that has simply been paid in hours.
Does fuel spend match miles and equipment
Fuel spend, miles and reported gallons should imply a plausible mile per gallon for the equipment described. An implied figure well outside the plausible range means the miles are wrong, the spend is wrong, or some fuel is going somewhere else. Any of those creates questions.
Is there a real reserve, or just an intention
A maintenance reserve that exists only as a line in a spreadsheet does not protect anything. What an underwriter looks for is a pattern in the operating account consistent with the business absorbing periodic large repairs without a payment being missed. That is a liquidity question, and it is where a lot of otherwise healthy carriers show weakness.
Per-mile accrual is the reserve that works
Pick a reserve rate appropriate to your fleet's mileage band, multiply by miles run, and move that amount to a separate account weekly or on each settlement. It is boring and it is effective, because it converts an unpredictable expense into a predictable one, and it produces exactly the balance pattern a lender wants to see.
Name the events you can schedule
Tires, brake cycles, aftertreatment service and, on high-mileage units, major engine work are not surprises. They are scheduled expenses with uncertain timing. Put each on a calendar with an estimated cost and the odometer reading you expect to hit it at, and the reserve target stops being a guess.
What to track, per unit
What to track, per unit
- Miles run, by month, separated into loaded and empty.
- Gallons purchased and total fuel spend, reconciled to your fuel tax filings.
- Computed miles per gallon by unit and, if you have drivers, by driver.
- Every maintenance and repair invoice coded to the unit, including parts you install yourself.
- Maintenance cost per mile by unit, updated monthly.
- Tire position history and remaining tread by axle.
- Preventive service intervals with next-due odometer readings.
- Warranty coverage and expiration by component, especially aftertreatment.
- Reserve balance against the target implied by your mileage band.
- A dated list of expected major events with estimated cost and odometer trigger.
Once it is set up, that list costs about twenty minutes a week per truck. It converts your two largest variable costs from opinions into evidence, which is what an underwriter is asking for, and what you need anyway to price a load honestly.
What maintenance reserve should I actually use?
Set it against your mileage band rather than a single industry number, and revisit it every time a unit crosses into a new band. The bands above are directional; the better input is your own trailing cost per mile by unit, which is why tracking it matters more than picking the right starting figure.
Does the fuel surcharge cover my fuel cost?
Partially at best. It typically lags the market, it is usually computed on loaded miles only, and on spot freight it is often folded into an all-in rate. Model fuel at what you actually pay across all miles and treat surcharge as revenue, so your break-even is not quietly optimistic.
Do lenders adjust the maintenance number I report?
Frequently, especially when the reported figure is implausible for the age of the equipment. The adjustment reduces adjusted earnings and therefore coverage, which can reduce the amount you qualify for. Bringing a defensible, documented number is the way to control that.
Is doing my own maintenance a positive or a negative?
Both, and it needs to be presented carefully. It genuinely lowers cash cost, which is a positive. But it also means your labor is uncompensated and that the business would face higher cost if you stopped, so an underwriter may normalize part of it. Show parts spend and service records so the discount is at least informed.
How much does idle time really cost?
Enough to notice. Extended idling consumes fuel while producing no miles, and it also adds engine hours that pull service intervals forward. The cost shows up twice (once at the pump and once in the maintenance curve) which is why idle percentage is worth reporting by driver.
Should I buy an extended warranty on a used tractor?
It depends on the mileage band and what is covered, particularly around aftertreatment and injectors, which are where the large surprise bills tend to come from. Read the exclusions and the claims process rather than the headline. A warranty that converts a variable risk into a fixed cost has real value, but only for the components it actually covers.
How do fuel network discounts factor into underwriting?
They show up in your actual cost per gallon, which is what matters. A meaningful discount improves your cost per mile and therefore your margin, and it is worth documenting when it is material. It does not change how the desk models the risk, only the numbers that go into the model.
My maintenance spiked last year because of one overhaul. How is that treated?
Usually as a non-recurring item if it is documented and genuinely one-time, but expect scrutiny, an overhaul on a high-mileage unit may be read as the start of a pattern rather than an exception. Support it with the invoice, the odometer reading and your service history so the case is on paper rather than in conversation.
Where to start
Pick one truck and compute its real numbers for the last twelve months: miles, gallons, implied miles per gallon, and every maintenance dollar coded to that unit. Divide the maintenance by the miles. Compare the result to what you have been assuming.
That single exercise usually tells you whether your cost model is honest, and it produces the documentation that keeps an underwriter from substituting a number of their own. Do it for every unit, then bring the schedule when you finance the next one.
Qualified Commercial Underwriting Desk
Credit and capital markets
The Qualified Commercial underwriting desk reviews commercial real estate, dealer and Main Street files daily. The Academy is written from that work (how files are actually read, priced and declined) rather than from a rate sheet.
Educational content only. Nothing here is a commitment to lend, an offer of credit, or tax, legal or accounting advice. Program terms, timelines and thresholds vary by lender, file and market conditions, and any figures shown are illustrative.