How to Compare E‑Bike Conversion Kit Specs Without Being Misled by Marketing

Comparing ebike conversion kit specs sounds straightforward until you start doing it. Motor wattage figures contradict each other across listings. Range claims swing wildly between identical-looking batteries. One kit advertises "1000W" while another calls its motor "500W" and they perform identically.

Marketing copy is crafted to make numbers look impressive rather than inform genuine decisions. This guide cuts through the spec sheet confusion—explaining what each number actually means, what to ignore, what to verify, and how to compare kits on a genuinely like-for-like basis.

Why Spec Comparisons Go Wrong

Before getting into individual specs, it's worth understanding the three mechanisms that make comparison difficult.

Peak vs. nominal wattage is the most pervasive issue. A motor might peak at 1000W briefly under maximum load while its continuous (nominal) rating is 500W. Both numbers are technically accurate. Marketing uses peak. Engineering uses nominal. When comparing kits, always ask: which wattage is being quoted?

Battery Wh vs. Ah creates another comparison trap. Two kits might list battery capacity as "13Ah"—but a 36V 13Ah battery contains 468Wh, while a 48V 13Ah battery contains 624Wh. The Ah number is identical; the actual energy stored is 33% more in the second case. Watt-hours (Voltage × Amp-hours) is the only honest battery capacity comparison.

What's actually included in the kit headline varies enormously. One kit's listed cost includes battery, sensors, display, tools, and charger. Another's covers only the motor wheel. Comparing headline prices without verifying inclusions is comparing incomparable things.

Spec #1: Motor Wattage — What It Really Means

Wattage is the headline number on every conversion kit. It's also the most commonly misrepresented.

Nominal (continuous) rating — what the motor can sustain indefinitely without overheating. This is the number that determines real-world performance.

Peak rating — what the motor can briefly deliver at maximum load. Often 150-200% of nominal. This number is frequently what gets advertised.

UK legal note: For road-legal EAPC use, maximum nominal output is 250W. Kirbebike's 250W front wheel kits are CE/ROHS certified at this rating, specifically for UK road compliance. For off-road and private land builds, higher nominal ratings from 500W to 4000W are available across the range.

What to check when comparing wattage:

• Ask specifically for the nominal (continuous) rating
• Check whether motor specifications show a named brand (e.g., SHENGYI for Kirbebike's 500W-750W geared motors)
• Verify CE/ROHS certification for road-legal kits
• Don't compare peak wattage claims across kits without nominal figures

Spec #2: Battery — The Most Important and Most Misrepresented Spec

Battery specifications deserve the most scrutiny when you compare ebike conversion kit specs because they determine real-world range, longevity, and safety—and they're the area with the most marketing inflation.

Capacity: Think Wh, Not Just Ah

Two kits both listing "13Ah" are delivering very different energy if one runs 36V and the other 48V. Always calculate Wh before comparing range capability.

Cell Brand: The Decisive Quality Indicator

The single most important battery spec is the cell manufacturer—and it's frequently absent from budget kit listings.

Named cell brands to look for: LG, Samsung, Panasonic. These manufacturers supply cells to the premium consumer electronics industry with consistent chemistry, verified degradation rates, and safety profiles.

Anonymous or unbranded cells: No independent quality assurance. Degradation rates unknown. BMS quality unknown. Safety under abnormal conditions unverified.

Kirbebike specifies LG cells across all battery options—from the 36V 7Ah EZ Rider kit battery through to the LG 21700 cells in the 52V 30Ah / 60V 20Ah high-capacity pack. The 48V 16Ah mid-drive kit battery is explicitly LG-supplied with 1,000+ cycle life rating. This level of specification transparency is directly comparable; anonymous cells are not.

Spec #3: Torque — The Hill-Climbing Number Nobody Talks About Enough

Wattage tells you how much power a motor consumes. Torque tells you how hard it can push. For UK terrain—particularly hilly commutes, mixed surfaces, loaded bikes—torque is often more relevant than wattage.

Hub motor torque is generally lower, ranging from 35-80Nm depending on motor size. The EZ Rider 250W kit provides 50Nm—adequate for flat and moderate terrain.

Mid-drive torque is substantially higher because the motor drives through the bicycle's gearing, multiplying mechanical advantage on climbs. The Tongsheng TSDZ8 delivers 140Nm through its dual torque sensor system—more than double a comparable hub motor's output on steep terrain.

Why this matters for spec comparison: A 500W mid-drive with 140Nm of torque outperforms a 1000W hub motor on sustained climbs. Wattage comparison alone would suggest the opposite.

Torque sensing vs. cadence sensing is a related spec that dramatically affects the riding experience. Cadence sensors detect whether the pedals are turning (binary). Torque sensors measure how hard you're pedalling and modulate assist proportionally. The TSDZ8's dual torque sensors deliver assist that feels natural—one Kirbebike customer notes completing a 23km hilly daily ride on level one assist, finishing with 80% battery, specifically because the torque sensing system manages power efficiently.

Spec #4: Motor Type — Hub vs. Mid-Drive, Geared vs. Direct-Drive

Motor type affects weight, efficiency, noise, maintenance, and suitability for terrain. It's a spec that marketing often obscures by emphasising wattage instead.

What to check when comparing motor types:

• Geared or direct-drive? (Geared motors freewheel; direct-drive offer regenerative braking potential)
• Front or rear wheel mounting? (Rear provides better traction; front easier to fit on most bikes)
• Is a named motor brand specified? (Kirbebike specifies SHENGYI for its 500W-750W geared motors)
• What is the stated motor weight? (Relevant for handling and spoke loading)

Spec #5: Controller — The Hidden Performance Differentiator

The controller is frequently the most under-specified component in kit marketing, yet it has significant impact on the riding experience.

FOC (Field Oriented Control) controllers modulate power delivery smoothly and efficiently, responding progressively to rider input. They run quieter and produce better efficiency at varying load conditions.

Square-wave controllers deliver power in stepped increments, producing a more on-off power feel, higher electrical noise, and lower efficiency at partial loads.

Amperage rating determines current capacity. The EZ Rider kit uses a 36V 14A FOC controller—the amperage matched to the motor's specification for optimal efficiency. Mismatched controllers (oversized or undersized relative to the motor) create either thermal stress or underperformance.

Waterproofing specification is relevant for UK conditions. The TSDZ8 mid-drive display carries an IP66 rating—a specific, verifiable weatherproofing standard. Listings that describe displays only as "waterproof" without an IP rating provide no meaningful specification.

The Inclusions Checklist: Comparing Like-for-Like

Before comparing any two kits on performance specs, verify that both include the same components. The difference between a "kit price" and a "complete system price" can be substantial.

What a genuinely complete kit includes:

Speed and Range: Reading the Claims Honestly

Speed claims are straightforward to verify against voltage and motor specification, but frequently overstated in marketing.

As a general guide for hub motors:

• 36V systems: 25-35km/h typical
• 48V systems: 35-50km/h typical
• 52V systems: 50-60km/h typical
• 60V+ systems: 60km/h+ capable

Range claims are where the most inflation occurs. Range is affected by rider weight, terrain, assist level, tyre pressure, wind, and temperature. A battery claiming "60km range" under ideal flat conditions with minimal assist delivers considerably less on hilly UK terrain with heavier riders on higher assist levels.

The Verification Checklist: 8 Questions Before Buying

Use these questions to cut through marketing on any ebike conversion kit with battery:

1. Is the quoted wattage nominal or peak?
2. What cell brand is in the battery? (LG/Samsung/Panasonic = verified; unbranded = unknown)
3. What is the battery capacity in Wh? (Voltage × Ah)
4. What cycle life is the battery rated for?
5. Is the controller FOC or square-wave?
6. What IP rating does the display carry?
7. Are sensors, tools, and charger included in the quoted price?
8. Does the supplier carry CE/ROHS certification for road-legal kits?

Conclusion

The ability to compare ebike conversion kit specs accurately separates purchases that deliver lasting value from those that disappoint within a season. The key is moving past headline wattage and range numbers to the specifications that actually determine performance and longevity: nominal motor rating.

battery Wh capacity and cell brand, controller type, display IP rating, and complete inclusion verification. Explore the full Kirbebike conversion kit range where every specification is transparently listed—from named LG cell batteries and FOC controllers to IP66-rated displays and CE/ROHS certification—giving you exactly the information needed to compare on a genuinely honest basis.

Frequently Asked Questions

What is the difference between nominal and peak wattage on an ebike kit? 

Nominal (continuous) wattage is what the motor can sustain indefinitely under load—the real-world performance figure. Peak wattage is the brief maximum output under maximum load, typically 150-200% of nominal.

How do I calculate actual battery capacity for range comparison? 

Multiply voltage by amp-hours to get watt-hours (Wh)—the only accurate energy comparison. A 36V 13Ah battery = 468Wh. A 48V 13Ah battery = 624Wh. Despite identical Ah figures, the 48V battery stores 33% more energy.

Why does battery cell brand matter when comparing conversion kits? 

Named cell brands (LG, Samsung, Panasonic) provide verified chemistry, consistent degradation rates, and tested BMS performance. Anonymous cells provide none of these assurances.

Is a mid-drive motor always better than a hub motor for UK terrain? 

Not always—it depends on terrain. For hilly routes, the TSDZ8 mid-drive's 140Nm torque and dual torque sensing deliver superior hill climbing and natural ride feel compared to equivalent hub motors.

What does IP66 rating mean on an ebike display? 

IP66 indicates the display is protected against powerful water jets from any direction—a meaningful specification for UK conditions involving rain, spray, and condensation. Displays described only as "waterproof" without an IP number provide no verifiable protection standard.