Bicycle frame shape – which frame suits you?

Are you looking for a new bicycle but unsure 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'll learn everything you need to know about possible frame shapes so that you feel completely comfortable on your bike! By the way, the shape doesn't really matter when you're sitting on the bike - but it does make a significant 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 trapezoid frame or a wave frame. Here you'll also learn about the advantages and disadvantages of the different frame shapes, which frames e-bikes have, what has become of the good old ladies' bike, and which frame shape is safest for children. Before we take a closer look at the three most common frame shapes, let's take a little trip back in time...

“Ladies' Bicycle” ... is (not) a Frame Shape!

Before bicycles became increasingly 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 from straight tubes.
• Bicycles for women had to have a lower top tube because women usually wore skirts. They could only mount a bicycle with a horizontal tube in the way by risking public scandal.

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

Today, this distinction is no longer really made, but the term “ladies' bicycle” still persists, although it has now been replaced by other names (you'll find out below which!).

Frame Shape 1: Diamond Frame

The diamond frame is often still referred to as a "men's bicycle," but this designation is as outdated as the term "women's bicycle." 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 triangle consisting of the seat stay and chain stay) roughly resemble the shape of a cut diamond, hence the name of this frame shape.

Road bike, hardtail, or touring bike – sports bikes usually 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 form 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 subjected to particularly strong loads, so a durable bicycle frame that can withstand a lot while weighing little is essential. That's why performance bikes have diamond frames.

→ For this reason,  sports bicycles, 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 sleek 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, it is significantly lowered towards the rear wheel. This frame shape is called slope frame but still belongs to the diamond frames. 

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

Advantages of bicycles with this frame shape:

• particularly stable
• light
• stiff frame construction possible
• torsionally rigid thanks to optimal power distribution
• slim tube diameters 
• easy to manufacture
• can be found in all categories, road 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 of 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 language, the English term "Wave Frame" has become established, among cyclists, a bike with this frame shape is still mostly a "ladies' bike" or a "bicycle with a low step-through." Also referred to as "cradle" or "swan neck frame" or "... with low top tube," the same frame shape is meant. Depending on the construction, the top tube may be completely omitted or placed 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 here, these bicycles can be mounted very easily and without much climbing. Therefore, they are particularly  comfortable. Another important point: If you want to heavily load your bike, mounting or dismounting with a high top tube can become a real challenge. The critical point is the wobbly moment when you stand on one leg and simultaneously have to keep the bike upright. 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, today the materials from which bicycle frames are made and the manufacturing processes are so advanced that you can even race over rough terrain with a women's bike without immediately fearing a frame break. A bike 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 generally 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 better damping!

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

→ The comfortable wave form is especially appreciated with City-Bike and touring bikes and also used for E-City bikes and E-touring bikes.

A wave frame offers a lot of choices

Wave frames are available 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 particularly many choices here!

The equipment of a bicycle with a 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.  Coaster brakes are also 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 frame bags usually don't fit either. All other attachments, mudguards, kickstands or luggage racks work without any issues. For this reason, 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 brakes

Frame shape 3: The trapezoid frame - the golden mean 

In a bicycle with a trapezoid frame, the top tube of the frame is attached in the middle of the seat tube. Now you may ask yourself: What is the difference from a slope bicycle frame in diamond shape? Quite simply: In the slope frame, the top tube ends lower but still at the end of the seat tube (which is shorter here). In the trapezoid 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 attaches 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 for those who still want to differentiate between women's and men's bikes, the trapezoidal frame offers the perfect mix for everyone. Trapezoidal frames work with dresses and skirts or pants, making them suitable for everyone. 

Advantages of bicycles with this frame shape:

• fairly 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 it's not quite true. Actually, two independent types of bicycles have emerged from two different frame shapes because there are hardtails and fullys 

➽ Fullys –  MTBs with full-suspension frames. For Full-suspension bikes, frame builders like to get creative; in principle, a full-suspension bike also has a diamond frame, but in reality, it depends on how the suspension is integrated. Often, not much of the diamond shape is recognizable.

➽ Hardtails – MTBs with a 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

In the construction of their E-Bikes , manufacturers usually adhere to the three presented frame shapes. In the E-Bikes of recent model years, there was mainly one principle: the drive should become as invisible as possible, so it was integrated into the bicycle frame until it was 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, and this can also be realized with all frame types. However, slightly more inconspicuous are light E-Bikes. They often have a rear hub motor, so the bulky drive at the bottom bracket is omitted. Here, the frames can be constructed almost like for a regular bicycle, only the battery is fitted into a tube.

Bicycles in women's and men's versions

There are especially with trekking bikes and city bikes occasionally the same model in a version for men and a women's bike version. The bike for men then has a diamond frame and the women's bike has a trapezoidal frame or a wave frame. Those who like to be on the road in matching outfits can look out for such bikes!

The direct comparison shows it: Same bike, different bike frame shapes! Image © Giant

What does the frame shape of the bike have to do with the seating position?

Actually, the frame shape is not directly related to the seating position on the bike. 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 bike; in principle, any frame could be built to pull you aerodynamically in length or to straighten you back-friendly. Here it depends on the geometry of the frame that is, on stack and reach or on dimensions such as the distance between the seat tube and the handlebars 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 still somewhat relaxed, is the geometry of the diamond frames of gravel bikes and many mountain bikes on the road. 
• The seating position on many trapezoidal frames is sporty, but still comfortable enough for long distances – and thus perfect for trekking bikes, city bikes, and cross bikes.
• Particularly upright is the seating position on a wave frame, that is, on a city bike, Dutch bike, or on some touring bikes.

Which bike frame shape suits you? The direct comparison

Here again, the different frame shapes at a glance

The right frame shape for children's bikes

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. 

➽ In order to mount and dismount it safely and quickly, a children's bicycle should have a wave frame . This does not mean, of course, that girls and boys should ride a "ladies' bike", as you have already read above, this term 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 bicycle 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 observe your child on the bike for a while. The more confidently they ride, the more likely they will handle a diamond frame and a sporty seating position.

The bicycle frame – 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, they existed 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 on a diamond, wave, or trapeze frame, another question, however, is the suitable frame size. If your bike has a frame that you like and that you can easily mount and dismount, 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 right bike accordingly.