If you've run a diesel bakkie through 2026, you've probably noticed something the DMPR's monthly announcements don't spell out directly: diesel's price moves have, more often than not, been bigger than petrol's — both up and down. That's not your imagination, and it's not random. It comes down to how diesel's Basic Fuel Price is calculated internationally, and which global disruptions hit it hardest. But October 2026 broke the pattern in a genuinely interesting way, which is worth understanding if you're trying to predict where November goes next.
The pattern, month by month
Pulling together the DMPR's own confirmed figures across 2026's adjustments:
| Month | Petrol 93 change | Diesel 500ppm change | Which moved more |
|---|---|---|---|
| May 2026 | +R3.27/l | Diesel broke R32/l for the first time | Roughly equal |
| September 2026 | +R1.34/l | +R2.94/l | Diesel, by over 2x |
| October 2026 | +R3.12/l | +R2.84/l | Petrol, for the first time in months |
Why diesel usually moves more
Diesel's international product price is generally more exposed than petrol's to two specific risks: shipping disruption (since a large share of the world's diesel is seaborne, and a shock like Strait of Hormuz tension or Red Sea shipping risk hits it disproportionately) and refining capacity (diesel requires more complex refining than petrol, so any region losing refining capacity — like reduced Russian output — tends to show up more in diesel's international price than petrol's). August 2026 is a clean example: petrol was largely protected by a slate levy cut that month, while diesel rose sharply on reported Russian export restrictions and tight refining capacity. September followed a similar shape — diesel's increase ran more than double petrol's in rand terms.
What changed in October
October's story was different in kind, not just degree. Brent crude surged from an average of $87.89 to around $101 a barrel over the review period — a broad, across-the-board move driven by continued Middle East conflict and reduced Russian oil output, rather than a diesel-specific shipping or refining shock. A crude price move that large affects the Basic Fuel Price for every grade roughly proportionally, which is exactly why October was the first month in a while where petrol's rand increase (R3.12-R3.33/l) actually matched or slightly exceeded diesel's (R2.84-R3.24/l).
Why this matters if you run a diesel vehicle
The practical takeaway isn't "diesel is always worse" — it's that diesel's monthly swings are genuinely less predictable than petrol's, in both directions. A month driven by a broad crude move (like October) tends to treat both grades similarly; a month driven by a shipping or refining-specific disruption (like August or September) tends to hit diesel disproportionately. If you're budgeting for a diesel bakkie's running costs, that unpredictability is itself worth planning around — a buffer in your monthly fuel budget matters more for diesel than for petrol, precisely because diesel's bad months tend to be worse than petrol's bad months, even if this particular month wasn't one of them.
For the real rand impact on specific bakkies, see our diesel bakkie running-cost breakdown for Hilux, Ranger and D-Max owners specifically.
Frequently asked questions
Figures above combine this site's own confirmed monthly fuel-price data with South African fuel-price news coverage (BusinessTech, IOL, Mining Review, Daily Maverick, Car Magazine) current as of mid-October 2026. Some months' exact pump-price deltas were affected by the temporary fuel levy relief being phased out independently of the Basic Fuel Price — see the levy relief article for that part of the picture. Always confirm current prices against this site's monthly fuel prices page.
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