Guide
Maintenance reserve per mile: smooth the lumpy months
Repair bills do not arrive evenly. A reserve per mile does. It turns a surprise into a line on every settlement.
In short
- Reserve per mile = total maintenance spend / total miles, from your own history.
- Set the reserve aside on each load, so the repair month has cash behind it.
- Use 6 months of data or more. One quiet month proves nothing.
- The reserve covers the average. A big failure can still exceed it. Keep a cash cushion too.
Hook. In the example, the repair spend ran from $650 to $4,100 a month, yet the reserve is a flat $0.24 a mile. The balance dipped to -$74 in month 3 before it recovered.
A flat rate for an uneven bill
Your cost per mile already has a maintenance line. A reserve makes that line real cash. You move it into a separate account as miles accrue.
The figure shows six invented months of repair spend as bars. Green months are covered by the reserve. Red months are not. The dashed line is the monthly reserve. Months 3 and 6 break it, so the balance carries them.
The first months can run negative if you start at zero. That is why a starting balance helps.
Set it up in five steps
Pull 6 months
Maintenance and tire spend plus miles for each month.
Divide
Total spend / total miles. Round up to the next cent.
Open a pot
A separate savings account or a tracked line in your sheet.
Move on each load
Loaded plus empty miles x the reserve, moved when the load pays.
Review quarterly
Recompute with the latest 6 months and adjust.
Six months, one reserve rate
| Month | Miles | Spend | Reserve added | Balance |
|---|---|---|---|---|
| Month 1 | 9,200 | $2,100 | $2,208 | $108 |
| Month 2 | 8,800 | $650 | $2,112 | $1,570 |
| Month 3 | 9,400 | $3,900 | $2,256 | -$74 |
| Month 4 | 9,000 | $800 | $2,160 | $1,286 |
| Month 5 | 8,600 | $1,200 | $2,064 | $2,150 |
| Month 6 | 9,100 | $4,100 | $2,184 | $234 |
| Total | 54,100 | $12,750 | $12,984 | $234 |
A reserve is not a forecast. It is a habit that turns an unpredictable bill into a predictable deduction. Review the rate each quarter against the latest 6 months. If the balance keeps growing, lower it. If the balance keeps going negative, raise it or find out which unit causes the spikes.
Where to hold the money matters less than keeping it apart. A separate savings account makes withdrawals visible. A line in a sheet works if you check it at month end. Pick the one you will actually look at, and write the rule for what counts as a draw: repairs and tires only, not fuel and not payroll.
Worked example EXAMPLE VALUES
Example data. Six invented months. Total spend $12,750 over 54,100 miles gives $0.2357 a mile, rounded up to $0.24. The starting balance is $0.
| Step | Result |
|---|---|
| Total spend | $12,750 |
| Total miles | 54,100 |
| Spend per mile | $0.2357 |
| Reserve per mile | $0.24 |
| Lowest balance | -$74 |
| Ending balance | $234 |
The lowest balance is -$74, in month 3, so a $0 start does not cover the first big repair. A starting balance of at least that amount would have. Month 6 spends $4,100 against a reserve of about $2,164 a month, and the balance still holds.
This is one invented history. Your numbers will differ. We do not project a yearly figure from six guessed months.
Where it goes wrong
- Starting at zero. The first big repair can arrive before the pot is full.
- Using one month. A quiet month gives a reserve that is too low.
- Raiding the pot. If fuel money comes from it, it is not a reserve. Track every withdrawal.
- Ignoring tires. Count them in the same history, or run them separately. See tire cost per mile.
The formulas
Round the reserve up, not down.
Your numbers decide
The numbers are invented. The reserve does not replace insurance, warranty or a cash cushion. Your truck age and routes change the right amount.
We do not give legal, tax or financial advice. Your contracts come first.
Questions
Which miles do I use?
All miles, loaded and empty. Wear follows the odometer.
Does it include tires?
You can include them or track them apart. Pick one and stay consistent.
What if my truck is new?
Early spend can be low and unrepresentative. Use your own history as it builds.
How is this different from cost per mile?
Cost per mile is the math. The reserve is the cash you set aside.
Related: truck downtime cost, seasonal cash cushion, 13 week cash flow, true RPM, month end close, all guides.
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