# Range & Performance Why your CEMOTO bike does not reach its published range or top speed — and what to do about it. --- ## First: understand what the published figures mean | Figure | Test conditions | | --- | --- | | **Maximum range** | Measured with a **70 kg rider**, ambient temperature **25 °C**, constant speed **20 km/h** | | **Top speed** | Manufacturer-stated maximum on private land or track, under favorable conditions | | **Charge time** | Full charge under normal conditions | These are **maximums, not guarantees**, and they are not achievable simultaneously — riding at top speed will not deliver maximum range. The owner manual states it directly: *"Due to different test environments, the values of cruising range will vary greatly."* --- ## What actually reduces range and speed | Factor | Effect | What to do | | --- | --- | --- | | **Rider weight** | Heavier riders consume more energy, especially on climbs | Nothing to fix — understand the effect when planning rides | | **Terrain** | Frequent uphill riding is the single largest consumer. Rough, loose surfaces also increase drag | Plan routes with climbs in mind; use pedal assist where the model has it | | **Wind** | Riding against the wind is equivalent to a continuous climb | Plan for it on exposed routes | | **Continuous high speed** | Drag increases with the square of speed. Riding at top speed dramatically shortens range | Use medium speed. The manual explicitly recommends driving at medium speed | | **Frequent braking and acceleration** | Every acceleration event draws a burst of current | Ride smoothly; avoid stop-start riding | | **Heavy load** | Carrying loads beyond typical use increases consumption | Stay within the rated maximum load | | **Tire pressure** | Under-inflation increases rolling resistance and reduces range. It also risks rim and tire damage | Check pressure before every ride | | **Low temperature** | Reduces usable battery capacity — see the table below | Accept seasonal reduction; store and charge at room temperature where possible | | **Battery age** | Capacity declines over the battery's life (average 1–2 years) | Understand when replacement is due — see [Battery Life](https://wiki.cemotoride.com/link/335) | | **Riding mode** | Higher power modes draw more current | Use a lower gear/mode for range-focused rides | | **Riding style** | Aggressive throttle use consumes more than steady progress | Be smooth | --- ## Symptom: range has dropped suddenly A **sudden** drop (rather than gradual seasonal or age-related decline) points to a fault rather than conditions. ### Check in this order **1. Tire pressure** This is the most common and cheapest cause. Under-inflated tires noticeably increase resistance. Confirm pressure with a gauge. **2. Brake drag** A dragging brake is a constant energy drain and a safety issue. - Lift the wheel off the ground and spin it. It should rotate freely. - Listen for pad rub. - Check the brake is adjusted with appropriate tension so it responds in time but does not drag. See [Brakes](https://wiki.cemotoride.com/link/328). **3. Cold weather** Compare against the degradation table before assuming a fault: | Battery temperature | Approximate available capacity | | --- | --- | | 14 °F | ~70 % | | 32 °F | ~80 % | | 70 °F | ~90–95 % | **4. Battery charge acceptance** Confirm the battery actually reaches a full charge. A charger that is failing, or a charging port that is not making good contact, produces a partial charge that looks like a range problem. See [Charging Faults](https://wiki.cemotoride.com/link/329). **5. Battery health** - A pack that reads normal voltage at rest but collapses under load has a failing cell group. - Where the discharge meter detects **less than 70 % of available capacity**, the battery may qualify for warranty replacement. **6. Parameters** - **P06** (wheel diameter) and **P07** (number of speed magnets) affect the accuracy of the distance and speed readings. **Incorrect values make the bike appear to have less range than it does**, because the odometer under-counts. Confirm these match your model. - **P14** (controller current limit) set too high increases consumption. See [Display & Settings](https://wiki.cemotoride.com/link/330). **7. Environmental and route changes** Have you changed route, terrain, load or riding style? A new hillier commute is not a fault. --- ## Symptom: the bike is slower than the published top speed | Cause | Notes | | --- | --- | | **Power gear** | The bike is in a lower gear. Select a higher gear. | | **Speed limit parameter** | Check **P08** (speed limit, 0–100 km/h). It may have been set for a restricted rider and not restored. | | **Low battery** | The manual notes that if the battery is low, the bike may not travel at a consistent high speed as expected. Charge for a better ride. | | **Controller current limit** | **P14** set low reduces available power. | | **Rider weight and terrain** | Both reduce achievable speed on climbs. | | **Factory compliance setting** | The controller ships with a factory-set limit for local compliance. It can be switched to competition-focused off-road settings where allowed. | --- ## Battery life | | Detail | | --- | --- | | **Average lifespan** | 1 to 2 years, depending on conditions and usage | | **Expected degradation** | Gradual capacity loss over the battery's life | | **Significant loss trigger** | Available capacity below 70 %, as measured by the discharge meter | | **Warranty term** | 12 months on the D-series | Rechargeable batteries do not last forever, even with correct use. Plan for replacement as part of the cost of ownership. Note that a battery replacement does **not** extend the original warranty period. See [Battery Care & Charging](https://wiki.cemotoride.com/link/321) for practices that extend battery life. --- ## Planning a ride: the range simulator CEMOTO provides an **Electric Bike Range Simulator** that models range against real-world inputs such as rider weight, terrain and assist level: **[Electric Bike Range Simulator](https://cemotoride.com/pages/electric-bike-range-simulator)** Use it before a long ride to set a realistic expectation, and build in a reserve. As a rule, plan to return with at least 30 % charge remaining — this protects the battery from deep discharge and gives you margin for a change of route. --- ## Related pages - [Charging Faults](https://wiki.cemotoride.com/link/329) - [Battery Care & Charging](https://wiki.cemotoride.com/link/321) - [Brakes](https://wiki.cemotoride.com/link/328) - [Display & Settings](https://wiki.cemotoride.com/link/330) - [Warranty](https://wiki.cemotoride.com/link/391)