Bicycle frame shape – which frame suits you?

You are looking for a new bicycle but don't know which frame shape suits you? You're not alone, many cyclists initially face the question of which frame type is best for them. No problem, here you will learn everything you need to know about possible frame shapes so that you feel completely comfortable on your bicycle! By the way, the shape is pretty irrelevant when you're sitting on the bicycle – but it makes a noticeable difference when getting on and off.

We explain here the three most common frame shapes, as most bicycles (and of course e-bikes) have a diamond frame, a trapezoidal frame or a wave frame. Here you will also learn the advantages and disadvantages of the different frame shapes, which frames e-bikes have, what happened to the good old ladies' bike, and with which frame shape children are the safest on the road. Before we take a closer look at the three most common frame shapes, let's take a little detour into the past…

“Ladies' Bicycle” ... is (not) a frame shape!

Before bicycles became more specialized for different purposes, there were mainly two frame shapes: 

• Bicycles for men had a high top tube, as frames could be easily and stably welded together from straight tubes.
• Bicycles for women had to have a lower top tube because women mostly rode in skirts. Therefore, they could only get on a bicycle with a horizontal tube in the way under public nuisance.

The frame shape, or rather ... the top tube made a bicycle a men's bike (right) or a ladies' bike (left). Images © Creme Cycles

Today, this distinction is actually no longer made, but the term “ladies' bicycle” persists, even though it is now replaced by other names (you'll find out which ones below!).

Frame Shape 1: Diamond Frame

The diamond frame is often still referred to as a “men's bike,” but this designation is as outdated as the term “women's bike.” The diamond frame is formed from two triangles, with the top tube running (almost) parallel to the ground. The two triangles of the frame (the main frame and the rear structure composed of the seat stay and chain stay) roughly mimic the shape of a cut diamond, hence the name of this frame shape.

Road bike, hardtail, or touring bike – sports bikes generally have diamond frames. Image © Trek

The diamond frame is the frame shape for athletes

Diamond frames are considered particularly stable, and indeed stable bicycle frames can be constructed in this shape with relatively thin tube diameters. The thinner tubes mean less material and thus also less weight. Even ultra-light carbon works particularly well in this frame shape.
In competitive sports, the bikes are exposed to particularly strong stresses, so a durable bicycle frame that can withstand a lot and yet weighs little is essential. That's why performance bikes have diamond frames.

→ For this reason,  sports bikes, such as hardtails, road bikes or gravel bikes always rely on diamond frames. The same applies to E-MTBs, E-gravel bikes or E-road bikes.

 The diamond frame shape is simply chic!

Even bikers who value a particularly clean look often opt for a slim steel diamond frame. Urban Bikes, Fixies and Singlespeeds are particularly striking representatives here.

With modern diamond frames, it goes downhill...

Today, the top tube of a diamond frame is often no longer horizontal; towards the rear wheel, it is significantly lowered. This frame shape is called Slope Frame but still belongs to the diamond frames. 

The crux with the diamond frame is the mounting and dismounting. Here, your leg somehow has to get over the top tube and the saddle. This usually doesn't require a yoga diploma, but it does require some flexibility and also good balance.

Advantages of bicycles with this frame shape:

• particularly stable
• light
• stiff frame construction possible
• torsion-resistant thanks to optimal power distribution
• slim tube diameters 
• easy to manufacture
• can be found in all categories, racing bikes, gravel bikes, city bikes, fixies/singlespeed or trekking bikes and touring bikes are available with this frame shape
• available in aluminum, steel, and carbon, also titanium frames are available; there is also ongoing experimentation with renewable raw materials and bicycle frames made from wood or bamboo are being brought to series production

Frame Shape 2: Wave Frame, Ladies Bike, Bicycle with Low Step-Through - the Comfort Bike

Many names, always the same bike... in technical jargon, the English term “Wave Frame” has become established, among cyclists a bike with this frame shape is usually still a “Ladies Bike” or a “Bicycle with Low Step-Through”. Also with “Cradle” or “Swan Neck Frame” or “... with low top tube” the same frame shape is meant. Depending on the design, the top tube is either completely omitted or attached as low as possible above the bottom bracket.

Bicycles with Wave frames and low entry offer maximum comfort. Image © Giant

Easy Entry - Cycling without Climbing

The advantage of these bicycle frames is obvious: Since there is no top tube in the way, these bicycles can be mounted very easily and without much climbing. Therefore, they are particularly suitable for casual riders  comfortable. Another important point: If you want to load your bike heavily, getting on or off with a high top tube can become a real challenge. The critical moment is when you're standing on one leg and have to keep the bike upright at the same time. A wave frame makes life significantly easier, especially when the "heavy load" consists of a squirming child in a child seat !

The frame shape for extra comfort

In the past, bicycles with this frame shape were considered less stable, but today the materials from which bicycle frames are made and the manufacturing processes are so advanced that you can ride over rough terrain even with a women's bike without having to immediately fear a frame break. A bicycle with a low entry might have slightly less frame stiffness , but since these bikes are rarely used in competitions where every tenth of a second counts, this is usually negligible. This supposed disadvantage is rather an advantage for many riders: They appreciate the slight flexibility of these bicycle frames, because some flex always means a better damping!

But you can expect not only additional damping, another advantage of these frames is the back-friendly riding posture. A bicycle with this frame shape often requires an upright posture, which is gentle on the back, neck, and arms, and you also have a better view ! 

→ The comfortable wave shape is especially appreciated in the City-Bike and the Touring Bike and is also used in the E-City Bike and E-Touring Bike.

A wave frame offers a lot of choices

Wave frames come in different versions, with and without a top tube, with two slim top tubes, with a straight tube, with a curved tube, and so on. So you have a lot of choices here!

The equipment of a bicycle with wave frame shape

Even in terms of equipment, these bicycles often offer simple solutions that make the bikes particularly user-friendly! On bicycles with this frame shape, you will often find hub gears, which are very easy to operate. Also, coaster brakes are not uncommon here.

What doesn't work so well with the wave frame is a bottle holder on the frame: It's simply complicated to attach the cage so that you can reach it while riding, and also frame bags generally don't fit. All other attachments, mudguards, kickstands or luggage racks of course work without any issues. These bikes are perfect for anyone who wants to mount a child seat on the bike or travel with large panniers . 

Advantages of bicycles with this frame shape:

• easy to get on and off
• particularly well-suited for mounting child seats
• many e-bikes with low or extra-low entry
• possibly slightly damping properties
• upright seating position, therefore good visibility and particularly comfortable 
• compatible with full equipment
• available with hub gears and coaster brake

Frame Shape 3: The Trapeze Frame – the golden middle 

On a bicycle with a trapeze frame, the top tube of the frame is attached in the middle of the seat tube. Now you might be wondering: What is the difference to a slope bicycle frame in diamond shape? It's simple: With the slope frame, the top tube ends lower, but still at the end of the seat tube (which is shorter here). With the trapeze frame, the top tube ends in the middle between the seat clamp and the bottom bracket.

Many e-bikes have trapezoidal frames. Image © Haibike

The trapezoidal frame is sporty and comfortable

A trapezoidal frame has a top tube that connects to the middle of the seat tube, allowing these bicycle frames to achieve good stiffness values and be very robust. But you can lift a leg through the frame and don't have to go over the saddle, which is not quite as comfortable as a low entry, but a good compromise. 

The trapezoidal frame is suitable for men and women!

As you already know, the separation between genders in the bicycle world no longer applies. But those who still want to distinguish between women's and men's bikes will find the perfect mix for everyone in the trapezoidal frame. Trapezoidal frames work with dresses and skirts or pants and thus for everyone. 

Advantages of bicycles with this frame shape:

• quite comfortable getting on and off
• stable enough for rougher paths
• relatively lightweight construction possible
• upright to slightly inclined seating position

There are two possible frame shapes for MTBs

Are there two different frame shapes for MTBs? You could say so, but that's not quite true. Actually, two independent types of bicycles have emerged from two different frame shapes, because there are hardtails and full-suspension bikes

➽ Full-suspension bikes –  MTBs with full suspension frame. With Fullys , frame builders like to get creative. In principle, a fully also has a diamond frame, but in reality, it depends on how the suspension is integrated. Often, not much of the diamond shape can be seen anymore.

➽ Hardtails – MTBs with rigid diamond-shaped frame. Hardtails are always based on a diamond frame, often on slope frames today.

In comparison, you can see the striking difference in the construction of the bicycle frame of the two mountain bikes. Images © Orbea and Santa Cruz

The frame shape of the e-bike

When designing their e-bikes , manufacturers mostly stick to the three presented frame shapes. In the e-bikes of recent model years, there was mainly one motto: The drive should become as invisible as possible, so they were integrated into the bicycle frame until they were hardly noticeable, which now works with every frame type. 

The batteries are now housed in a slightly thicker down tube in most e-bikes, which works with diamond, trapezoidal, and wave frames.

The drive itself is mounted on the bottom bracket, which can be realized with all frame shapes. However, slightly more inconspicuous are light e-bikes. They often have a rear-wheel motor, so the bulky drive on the bottom bracket is omitted. Here, the frames can almost be constructed like for a bio-bike, only the battery is fitted into a tube.

Bicycles in women’s and men’s versions

Especially with trekking bikes and city bikes, the same model sometimes comes in a men's version and a women's bike version. The men's bike then has a diamond frame and the women's bike has a trapezoidal frame or a wave frame. Those who like to travel in matching outfits can look for such bicycles!

The direct comparison shows it: Same bicycle, different bicycle frame forms! Image © Giant

What does the frame form of the bicycle have to do with seating posture?

Actually, the frame form is not directly related to the seating posture on the bicycle. Whether the frame has a high top tube or not has nothing to do with whether you sit more upright or stretched out on the bicycle; in principle, any frame could be built to make you aerodynamic or back-friendly. It depends on the geometry of the frame , such as stack and reach or on dimensions like the distance between the seat tube and the handlebar or the frame height.

Nevertheless, there are the following tendencies in the "geo":

• On a racing bike, you sit with your nose just a few centimeters from the (diamond) frame.
• Low, but somewhat more relaxed is the geometry of the diamond frames of gravel bikes and many mountain bikes. 
• The seating posture on many trapezoidal frames is sporty, but comfortable enough for long distances – and thus perfect for trekking bikes, city bikes, and cross bikes.
• The seating posture on a wave frame is particularly upright, such as on a city bike, Dutch bike, or some touring bikes.

Which bicycle frame form suits you? The direct comparison

Here is an overview of the different frame forms again

The right frame shape for children's bicycles

The most important thing is that small children  they can safely handle their first children's bicycle and there are two aspects that are particularly important. 

➽ To be able to safely mount and dismount quickly, a children's bicycle should have a wave frame . This of course does not mean that girls and boys should ride a "ladies' bike," as you have already read above, this designation is no longer current. But the low entry helps them to easily climb onto the bike and - more importantly - to quickly dismount in an emergency. 

➽ The smaller the child, the better an upright seating position on the bike is. The higher the head, the better your child can see and be seen. Sporty and low comes later, younger kids are best brought into an upright seating position by the frame geometry!

For older children, it helps you decide if you watch your child on the bike for a while. The more securely they ride, the more likely they are to manage with a diamond frame and a sporty seating position.

The bicycle frame - just a matter of form?

There are other frame shapes, but they mostly differ in details from the three main shapes: diamond, trapeze, and wave. A rather exotic creation was Y-frames, which were available in the nineties; today, this frame shape has become rare. Also cross frames are more of a fringe phenomenon. 

A type of bicycle where you will encounter all possible frame shapes are folding bikes or compact bikes, whether they are foldable or not. Here, manufacturers often deviate far from the common frame shapes of other bicycles to create stable frames with the smallest possible dimensions. 

But most cyclists ride a diamond, wave, or trapeze frame; another question, however, is the appropriate frame size. Even if your bike has a frame that you like and that you can get on and off easily, you still need a bike that fits your size!

We also have a guide for you here. In our article "How to determine the right frame size for your new bicycle," you will learn how to first measure your leg length and then choose the appropriate bicycle.