Tripmeter distances and corrections
The roadbook and tripmeter need to describe distance from the same reference. Printed total is cumulative from the section origin; printed partial is the fixed interval between diagrams. The live instrument partial counts from its last reset. It is not a countdown and does not rewrite the printed interval.
| Reference | Total |
|---|---|
| Previous row | 12.40 km |
| Current trip | 12.90 km |
| Next row | 13.15 km |
Calculate the next interval
One row is at 12.40 km and the next is at 13.15 km. The interval is 13.15 − 12.40 = 0.75 km, or 750 metres. If the tripmeter is aligned and reads 12.90 km, about 0.25 km remains to the next row.
Correct only at a confirmed feature
With rider-operated correction selected, you positively identify the junction printed at 12.40 km, but your total trip reads 12.55 km. Adjust TOTAL down by 0.15 km to 12.40 km. PARTIAL keeps its reading unless you separately reset it. This aligns one known point; it does not prove the sensor is calibrated for the rest of the route.
Do not correct away uncertainty
If you are unsure which junction you reached, changing the tripmeter to match a guessed row can hide the error. Stop somewhere safe, compare the route features and work from your last confirmed position. Know which control changes total distance and which resets the partial counter.
Choose the sensor and procedure separately
Paper or digital describes how you read the book. Wheel-sensor or GPS describes how distance is measured. Automatic event-GPS recalibration or rider-operated correction describes how the reading is aligned. Rally School keeps these choices separate. A detour adds real distance; front-wheel pulses do not automatically increase because the rear wheel spins.
Check your understanding
At a confirmed 8.20 km landmark your trip reads 8.05 km. Which correction aligns the total?
Show the answer
Increase the displayed total by 0.15 km to 8.20 km. The tripmeter is behind the roadbook at that point. Do not reset it to zero unless the roadbook explicitly establishes a new zero there.
These are simplified training examples. For an event, follow its roadbook, briefing and equipment instructions. See the field guide and its sources for the wider navigation context.