How do you choose the right electric bike size?

Updated on 5 November 2026. Recommended products are available at the time of the update.

To choose the right electric bike size, start with your height and inside leg measurement, compare them with the model's size chart and check your riding position. On a city e-bike, you need to get on, stop and set off again easily; on an e-MTB, you also need room to move on the pedals. In both cases, try manoeuvring the bike by hand: the right size should also allow you to control its weight.

How to choose

The size labels S, M and L are not the same across all bikes. Even two frames marked with the same number can offer different riding positions: the overall geometry matters, not just the seat tube height.

• Measure your height and inside leg. For your inside leg, stand barefoot against a wall and measure from the floor to the top edge of a book held between your legs. Use these measurements as a starting point in the model's size chart.
• Check the distance to the handlebar. You should be able to reach it without overstretching your arms or tensing your shoulders. Reach describes how far the frame extends forwards relative to the bottom bracket; stack describes its height up to the top of the head tube.
• Check the clearance above the frame. When you get off the saddle and stand astride the bike, you should be able to manage a stop without hitting the top tube. This measurement is often called standover.
• Adjust the saddle for pedalling. At the bottom of the pedal stroke, your knee should remain slightly bent, without your hips rocking. Observe the seatpost insertion limits.
• Try the brakes and controls. You should be able to reach the levers while maintaining a secure hold on the grips. Check whether the lever reach is adjustable.

If you are between two sizes, compare them on the same model. A smaller size may feel more compact, a larger one more stretched out: there is no automatic choice that works for everyone. The saddle and stem allow adjustments, but cannot compensate for a frame that is far from the right size for you.

City e-bikes: ease of access and safety when stopping

In town, you get on and off frequently. A low step-through frame makes it easier to get your leg across, but you still need to check the minimum saddle height and distance to the handlebar.

• Try getting on and off wearing your usual shoes.
• Simulate a stop: get off the saddle and place one foot securely on the ground.
• Check that you can turn the handlebar during tight manoeuvres without feeling restricted.
• If you will use bags on the rack, consider how the load will change the balance when stationary.

You do not need to get both feet flat on the ground while seated if this means setting the saddle too low to pedal properly. If you find stopping difficult, consider the geometry, ease of stepping through the frame and stopping technique together.

E-MTB: room to move and control on trails

On an e-MTB, the size must also work when you pedal standing up. With the pedals level and your elbows and knees slightly bent, you need room to move your body without feeling too stretched out or cramped.

• Check the reach. It affects the space available when riding standing up.
• Check the dropper seatpost. Fully extended, it should provide the correct pedalling height; lowered, it should leave room to move.
• Try cornering and braking. On an easy route, check that you can change direction and come to a stop gradually.
• Consider your experience. A bike you can handle without hesitation helps build confidence.

For help choosing the type of suspension too, read Mountain bikes: how to choose between hardtail and full suspension.

Weight matters even when the motor is not helping

The assistance supports your pedalling, but you have to manage the bike yourself when manoeuvring from a standstill. Weight distribution, as well as the stated weight in kilograms, changes how it feels when you lean or push it.

• Push it with the motor switched off and try a tight turn.
• Check that you can hold it when it leans slightly towards you.
• Assess the actual route to where you park: ramps, thresholds and stairs may influence your choice.
• If you need to load it into a car, try the manoeuvre in practice and check whether the battery can be removed.
• Check the manufacturer's total weight limit, accounting for the bike, rider, accessories and luggage according to its instructions.

Small wheels and a folding frame do not guarantee a low weight. Walk assistance, where fitted, should also be tested: it does not replace the ability to support the bike.

Small sizes: what to check beyond the letter S

A 26, 27,5 or 29 inch wheel indicates the wheel diameter, not the frame size. Even a bike with 20 inch wheels can have a riding position that is too stretched out or a saddle that is too high for its rider.

• Minimum saddle height: check it on the complete bike, especially with a suspension or dropper seatpost.
• Dropper seatpost insertion: check how far it can slide into the frame and how high it reaches when fully extended.
• Handlebar and levers: check the width, reach and how easily you can grip them with your hands.
• Room for feet and knees: try pedalling and steering slowly, checking for any contact.
• Control when stationary: a small size does not automatically make the bike light.

An e-MTB for a young rider should be chosen according to their measurements and abilities. Avoid choosing a larger size simply to allow room to grow.

Used MTB e-bike in size S: checks before buying

If you are looking for a «used electric mountain bike in size S», first identify the model, year and actual frame size. Find the original size chart: the size designation in the listing alone is not enough.

• Confirm the size on the frame. Compare the label, geometry and available documents.
• Check for modifications. A stem, handlebar, fork or seatpost that differs from the original specification can change the riding position and handling.
• Check the adjustments. The saddle must reach your required height without exceeding the seatpost limits; the dropper seatpost must operate without sticking.
• Inspect the mechanical components. Look for frame damage and have the headset, wheels and suspension checked for play, along with the brakes and drivetrain.
• Have the electrical system checked. Check the battery mounting and condition, contacts, charger, errors and assistance operation. Ask for a diagnostic check compatible with the system: the mileage on the display is not enough to assess the battery.
• Carry out a thorough test ride. Pedal seated and standing, brake, turn and push the bike with the motor switched off.

A good deal only remains one if the bike is the right size for you and its condition is clear.

Our recommendations, available now

These models from the Electric Bikes collection offer different starting points. Always compare the listed sizes with your body measurements.

Fantic Living City Electric City Bike

It is suitable for everyday city travel and has a low-step aluminium frame. It is offered in sizes M and L with 29-inch wheels, a Yamaha PW S2 motor and a 630 Wh battery.

Fantic Living Easy Electric City Bike

For those who alternate between everyday travel and rides beyond the city centre, it is offered in sizes S/M and L/XL. The specification includes 29-inch wheels, a 100 mm Suntour fork and a suspension seatpost.

Myland Big Handy SUV 26" Mid-Drive Electric City Bike

It is an option for those who ride in the city and also want to venture onto unpaved tracks and trails. It is available in size 43 with 26-inch wheels, a OLI Sport mid-drive motor delivering 85 Nm and a removable 602 Wh battery.

Torpado Explorer T350 Folding E-Bike

It is suitable for urban travel and those looking for a bike that can be stored folded, thanks to its folding aluminium frame and 20-inch wheels. It includes a removable 360 Wh battery, a Shimano 6-speed rear derailleur and walk assistance.

Trek Rail+ 5 Gen 5 2027 Full-Suspension MTB E-Bike Bosch Performance Line CX

It is designed for enduro and demanding descents, with 160 mm of travel front and rear and a removable 800 Wh battery. The specification lists size S for heights of 155-165 cm: an initial guide to check against your inside leg measurement and riding position. In size S, the dropper seatpost has 100 mm of travel.

Scott Patron 920 Full-Suspension MTB E-Bike Bosch Performance Line CX

It is aimed at those tackling demanding trails and climbs, with 150 mm suspension travel and a 800 Wh battery. It is offered in sizes S, M, L and XL; on size S, the dropper seatpost has 125 mm of travel.

For shipping information, see the shipping policy.

Let's find the right size in Casapulla

Evolution Bikes has been a family-run shop in Casapulla, in the province of Caserta, since 1974 and is now in its third generation. Come and try the riding position and have the bike adjusted: with our workshop, bike fitting and e-bike support, we can help you assess size and control. For advice before visiting, contact us.

Frequently asked questions

How do I work out the right electric bike size?

Compare your height and inside leg measurement with the model's size chart, then check the reach to the handlebar, saddle height and how easily you can stop. Also try pushing and supporting the bike with the motor switched off.

What rider height is a size S e-MTB suitable for?

It depends on the model and its geometry: there is no universal range. Consult the specific size chart and also check your inside leg measurement, standover clearance and minimum saddle height.

Is an electric bike with 26-inch wheels suitable for a shorter rider?

Wheel diameter does not determine frame size. You need to check the geometry, minimum saddle height and reach to the handlebar, even on bikes with small wheels.

What should I check on a used MTB e-bike in size S?

Confirm the model, year and actual size, then check that the saddle and controls can be adjusted to suit you. Have the frame, suspension, brakes and drivetrain checked, along with the battery and electrical system, and take a test ride before completing the purchase.