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Road E-Bike Size Chart for Adults & Kids

When you buy a road Ebike, there are many things you need to consider. In addition to finding the right type of Ebike, e.g. road bike, mountain bike, etc., you also need to pick the correct bike frame size. Since bicycles aren’t getting any less expensive, you need to ensure that you’re asking the right questions. The guide below includes information about how to size ebike frames for adults and children and as well as some information about whether to involve gender in the sizing process. Key content from this post is adapted with permission from Bicycle New England.

E-Bike Sizing Essentials

You can’t get the frame size wrong. If it is, things are bound to get dicey as you most likely won’t be comfortable and riding with an incorrectly-sized frame is downright dangerous. In some cases, you my be exacerbating health issues; especially in cases where risk factors are high. Lower back pain, elbow pain, neck pain, and knee pain can all be indicative of a poor fit (among other issues).

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Step 1: Measure Your Frame Size

EBike frame sizes are based on the height of the ebike. To determine the correct height of the hike,  measure the length of the seat post tube (see image above). This measurement is expressed in metric (cm) for road bikes, and imperial (inches) for mountain bikes.

Step 2: Get Your Measurements

To figure out the right frame size, you need to take a few measurements:

  • Your leg inseam
  • Your torso length
  • Your arm length

Leg inseam is the most common measurement you’ll see as you pick the right ebike frame size. Many bike size charts also reference stand-over height. This measurement refers to your leg inseam plus another 1-2 inches for comfortable clearance of that top tube. Some sizing guides claim that road ebikes need one to two inches of clearance while mountain or commuter bikes need two to four inches.

Another common formula is that of the top tube length. Finding a road bike that is on the compacter side with a shorter top tube makes a big difference; so don’t overlook this measurement. If you have a short torso, the distance between the saddle and the handlebars can really affect your ride. To determine your ideal top tube length, try the following:

(torso length + arm length) / 2 = x

x – 6 = top tube length

(Add your torso length to your arm length, divide that by two, and subtract six). This will tell you in inches what the ideal distance would be between your seat and handlebars.

If your bike has the right frame size, you will also be able to comfortably stand over the cross bar. You will be able to stop safely, rather than having to fall sideways until your foot hits the ground…ouch!

If your bike is too small, your knees and back may start to hurt, and you won’t be able to use your leg power efficiently.

Height and Inseam Length

The two most important measurements to know are your height, and your inseam length (the distance from your crotch to the end of your pant leg). Of these two lengths (height and inseam), inseam is the most important.


Arm Length

Your arm length measurement becomes important if your height and inseam measurements put you in between sizes. In that case, use your arm measurement to decide.

You need to know if you have a long or short reach, which means you need to find out your “ape index” (which is your arm span compared to your height).

  • If you have a positive ape index (your arm span is greater than your height) then you have a long reach and you should probably go for the larger of the sizes.
  • If you have a negative ape index (your height is greater than your arm span) then you have a short reach and you should probably go for the smaller of the sizes.

For example, say you have an arm span of 160 cm and a height of 160 cm. This would mean your arm span is exactly the same as  your height. So you have an ape index of 1, and therefore an average reach. However, if your arms are shorter, you have a short reach, so if you are between frame sizes, go for the smaller frame size.

Two Different EBike Frame Size Systems

Just to make it a little more challenging, there are two different bike-sizing systems. There’s one system for road bikes, and then a different one for mountain bikes and hybrid bikes. Sizes are given in metric (cm) for road bikes, and imperial (inches) for mountain bikes.

You can figure out your ebike frame size with the EBike Frame Size Guides below

Even with the right frame size, if you are planning to do a lot of cycling, you should still get your bike fine-tuned with a professional bike fitting, if you can afford it. If you are buying a new bike, try to find a bike shop that offers some help with bike fitting. Some of them are especially good with this, and will give you a professional level of help. (Many of the smaller bike shops cannot afford this, however.) Getting a well fitting bike will protect you against back pain or cycling knee pain.


Step 3. Consider Buying a Gender-Specific Frame

On average, women tend to have longer legs and shorter torsos than men of equivalent height. Women specific ebikes offer smaller frame sizes, shorter top tubes, narrower handlebars, female specific saddles and smaller brake handles.

However, you are unique, and a women specific ebike may not be right for you, even if you are a woman. The ebike you choose should be the perfect fit for you individually, regardless of gender.

If you are shorter than about 5 ft 5 in (165 cm) or have felt too stretched out on unisex ebikes before, you may be more suited to a women specific ebike. Try them out and see what works for you. I have known women who have been absolutely ecstatic on riding their first women specific ebike, because for the first time they felt like the bike really fitted them. On the other hand, other women find no benefit in them.

Also, bear in mind that if you are a short man, a woman specific bike may be right for you. No one needs to know! The reality is that the average male height in some countries is shorter than the average female height in others. For example, average male height in Indonesia is 5 ft 2 in, while average female height in The Netherlands is 5 ft 7 in (must be all that cycling that makes them grow so tall and strong)! So obviously, we cannot really generalize too much about this matter. Everyone is unique.

Step 4: Select a Frame for Your Child

Kid’s bikes are measured and sized differently. Often they are categorized in age ranges and wheel sizes, as you can see from the table. But keep these points in mind: