Lightweight Electric Bicycle: Balancing Weight and Performance

A lightweight electric bicycle isn't just a run-of-the-mill bicycle fitted with a little motor.

The weight of the battery, motor, controller, wiring, display, brakes, reinforced frame sections, accessories, etc. all contribute to the weight. This means that in order to reduce the final weight, engineering decisions need to be made throughout the entire bicycle, and not just with regard to the single part replacement.

This is why it's not necessarily the lightest bike that's the best for you, either. An extremely small battery might save weight, but provide a shorter range. Skinny tires can be more efficient, but can make driving on streets that have been damaged less comfortable. Rack, mudguards, or lights can be taken off to create a pretty spec but that decreases functionality on a daily basis.

The desired outcome is not just achieving a low weight, whatever the cost. It is the minimum complete weight which fulfills the rider's route, comfort, safety and ownership needs.

The Zoulaglide electric bike buyer's guide is a great starting point to look at various bike frame designs, battery sizes, motor setup, riding range, and uses.

 

Electric Bicycle Weight is a Full-system Number.

Different manufacturers may measure different parts of the total weight of an electric bike, since it is published by the manufacturer.

When comparing two models, before comparing, make sure that the figure contains:

lthe battery;

lpedals;

lmudguards;

llights;

lrear rack;

lkickstand;

lshow and manage equipment;

lStandard Tires and inner tubes.

Several kilograms lighter is the bicycle without its battery that is advertised without it. Another difference between the figure in the catalogue and the actual bike ridden day to day can be the optional racks and baskets.

It's important to compare the ready to ride weight, not just frame weight.

 

The weight of the frame is only a piece of the weight budget.

Weight is a major factor with frame materials, but frame names don't necessarily tell the whole story.

 

Aluminum alloy is popular for light electric bicycle frame due to its reasonable performance of strength and weight and the corrosion resistance. But other factors, such as diameter of the tubes, thickness of the tubes, the design of the welds, where motors are mounted, how batteries are integrated, and reinforcement around the joints, all affect the outcome.

A lighter frame will need to be adequately stiff around:

lHead tube/steering area;

lMounting points for motor and rear wheels;

lthe battery compartment;

lbrake attachments;

lrack or loading and unloading points;

lHinges (when applicable) are called folding hinges.

Some designs can be lighter with carbon fiber, but might require different inspection/repair methods and could be higher in cost. Steel is generally heavier, but can be engineered to give a compliant ride and durability.

The frame should be considered as load bearing system, not based on material alone.

Component	Included in Published Weight?	Weight to Confirm	Why It Matters
Battery	Yes / No	Complete battery weight	Changes lifting and riding mass
Pedals	Yes / No	Pair weight	Sometimes excluded from specifications
Mudguards	Yes / No	Front and rear set	Common commuter equipment
Rear Rack	Yes / No	Rack plus mounting parts	Affects rear balance
Lighting	Yes / No	Front, rear, and wiring	Essential for normal road use
Kickstand	Yes / No	Stand and bracket	Often fitted after measurement

 

The biggest sacrifice is created by Battery Capacity.

The battery sometimes can be one of the heaviest single parts of an electric bicycle.

The more cells the greater the capacity which allows for longer assisted rides, however, the more cells means greater weight and volume. For riders who do not normally use the largest available battery in their rides, but rather make a shorter round trip, this may be unneeded.

A better way to do this is to compute:

laverage daily distance;

lelevation gain;

ltypical assistance level;

lBike and rider weight;

lcharging opportunities;

lReserve for cold weather or for windy days.

But energy efficiency is important as well as capacity. A more streamlined bike that has an efficient tire setup, proper gearing and responsive pedal assist could get you where you need to go without having to carry a large battery.

A detachable battery also can alter the weight distribution. The bike can be the same weight before and after the battery is taken out but be lighter to lift.

 

Size of the motor should be proportionate to the route.

A larger motor can provide a better acceleration or increase the ability to handle hills but can increase weight, the size of the controller, the weight of wiring and frame interfaces, and battery size.

In urban routes, which are quite flat, smooth and efficient help can be more helpful than a high peak output, depending on the circumstances. If the trip is longer and/or frequent cargo carrying, the extra motor power can be worth it despite the extra weight of the final product.

Handling is also determined by the placement of the motors. A hub motor is where the weight is focused in one wheel, whereas a mid-drive is where it's focused towards the middle of the bike. There is no right or wrong layout – it is up to the rider to decide what is best for them based on their balance, maintenance, wear of the drivetrain and the type of terrain ridden.

Weight loss shouldn't set up a underpowered system, running close to its limits on each ride.

Wheels and tires – comfort is not all that's different.

Wheel and Tyre Selection affects Rotating Weight, Acceleration, Rolling Resistance, Grip and Vibration.

Thin treads, narrow tyres typically promote effective pavement travel. The broader the tire, the more stable it is and the more comfortable, but the heavier it will be and it will consume more energy.

Larger diameter wheels provide smooth rolling over irregularities on the surface, smaller diameter wheels can also provide smaller overall size and enable easier maneuverability. The right one would be the one which is used for either of the following:

lsmooth city streets;

lbroken urban pavement;

lpark paths;

llight gravel;

lfrequent start-stop riding;

llonger-distance commuting.

Limiting the protective properties of the tires for the purposes of weight reduction can lead to more frequent interruptions of maintenance and greater risk of punctures. When it comes to lightweight design, reliability needs to be taken into account along with grams.

Lesser-known accessories can make a huge difference in the final weight.

Most bikes that are sold out of the store are not left without extra adornments.

Popular add-ons include a basket, a bottle, a tool kit, phone mount, panniers, a rear rack, lights and mudguards. All these can add up to make a big difference with regard to the ready-to-ride weight and balance.

That doesn't mean that accessories are a no-go, though. It would mean that they should be built in the initial design.

Where possible opt for accessories that serve more than one purpose. For instance, an integrated rear rack could be more efficient than having multiple layers of overlapping cargo. Equipment which is required for safety should never be reduced for a lower number.

Zoulaglide's electric bike accessories collection illustrates the impact of tires, lights, seats, mudguards, pedals and more additions on the end result.

Lower Weight = Change the Riding Experience.

A lower bike mass will have an effect of increasing:

lTraffic light based acceleration;

llow-speed maneuverability;

lsteering response;

llifting and repositioning;

lunassisted pedaling;

lThe amount of energy consumed when accelerating multiple times.

However, the total mass of the system comprises the mass of the bicycle, rider, load and any accessories. If you remove 2 kg from the bicycle, there is a greater percentage difference for a lighter rider without the pannies as compared to a heavier rider with the pannies.

At higher speeds aerodynamic drag also becomes a significant factor. If you're on a level, flat surface, posture, tire pressure, wind and assistance level may have a greater impact on battery range than weight reduction.

Lightweight design features offer the biggest benefits when climbing, accelerating, handling and moving physically.

The E13 as the Lightweight Full-Size Example

The Zoulaglide E13 shows that a light electric bike can still be a full size urban/trekking bike.

It's currently listed as having a high-strength aluminum alloy frame, 250W brushless motor, removable 36V 10.5Ah Samsung lithium battery, 700×40C air tires and hydraulic disc brakes and a full weight of about 19 kg.

The design is surprisingly a balance between not being too small or light and not compromising on the size of the wheels, removable charging or on extended pedal-assist range.

This range will still be subject to assistance level, rider weight, gradients, weather conditions, wind, TPR and rider speed. Thus, the published weight/range must be seen as belonging to the same system and not as individual promises.

To further illustrate this, Zoulaglide has shared some comments on lightweight frame performance which also highlight the importance of considering frame strength, braking and weight in tandem.

 

Cars that are 600 pounds heavier today are still 500 pounds lighter than 40 years ago.

Before selecting a light electric bike, it's a must to determine the advantages that lighter weight would bring.

When the bike has to be taken up the stairs, the weight to lift is essential. If you are making frequent stops in the city, responsive handling might be a more important factor to consider. If you are going to be riding for long distances then battery capacity and riding position may make a few extra kilos worth it.

Test models in the situation that they will face in the course of the route. Add the battery, accessories, lock and regular load.

A properly engineered light e bike ought to be improved without being insufficient. The lowest number is NOT the best result, but a bicycle that keeps the qualities desired for normal use, such as range, stability, braking, comfort and equipment.

Any other ownership issues can be addressed by reading through the Zoulaglide FAQ.

Proposed Weight Reduction	Possible Benefit	Possible Compromise	Decision Question
Smaller Battery	Easier lifting	Shorter usable range	Can the daily route retain a reserve?
Narrower Tires	Lower rotating mass	Less cushioning and grip	Are roads consistently smooth?
No Rear Rack	Lower rear weight	Reduced carrying ability	Is cargo never required?
Lighter Saddle	Small weight saving	Reduced comfort	Has it been tested over normal distance?
Smaller Motor	Lower system weight	Less hill and load support	Does the route remain mostly flat?
Carbon Components	Lower weight	Higher cost and repair sensitivity	Is the saving meaningful for the use case?

 

FAQ

Q1. What's the "lightweight" weight of an electric bike?

While there's no set limit, full-size electric bikes that are about 17-22kg are considered light. When comparing figures these items must be included: Battery, accessories, wheel size, and what it is being used for.

Q2. Is there any connection between weight and range of an electric bike?

Not automatically. Weight savings can make a difference in the amount of energy used when accelerating and climbing, though energy-saving benefits might be more significant with battery capacity, wind, tyre pressure, terrain and assistance level.

Q3. Do the frames of e-bikes made from aluminum have longevity?

With a properly engineered aluminium frame, you can be assured of a strong and durable structure with a relatively low weight. The importance of frame geometry, welding, reinforcement, load rating and quality control are still important.

Q4. Does an electric bike have a removable battery make it lighter?

It doesn't save any weight, but enables the movement of the bicycle and battery as separate components. This may help make stairs, loading of vehicles and charging indoors easier.

Q5. Are larger tires OK for a lightweight e-bike?

Yes, but generally with an increase in weight and rolling resistance along with the wider tires. For longer routes where more comfort, grip or stability is needed, they might be worth considering.