Step-through or Top-tube? Comparing traditional “double diamond” and low-step bicycle frames

Step-through or Top-tube? Comparing traditional “double diamond” and low-step bicycle frames

The history of bicycle frames was forever changed when the low step (or "step-through") bike frame was invented in the 1880’s. Originally designed for women to ride, the lack of a high bar at the top of the frame made it easier to accommodate long dresses and skirts, and was deemed more civilized compared to the thought of women swinging their legs over the high bar.

For decades, low-step frames were considered to be solely for women, limiting their appeal to the masses. This has changed in recent years, as the stigma of low step bike frames as “women’s bikes” has waned. People of all walks of life are discovering how step-through bicycle frames can be more helpful for their specific riding style. 

While both top-tube and step-through bicycle frames have their own distinct advantages, it’s important to consider both options to see what will work best for your individual needs. In this article, we’ll examine all the ways that your bike's frame can make or break its fit for you.

Advantages of a top-tube frame

The double diamond frame bicycle has been the most popular and enduring frame style throughout the history of the bicycle, and for good reason. Denago's City Model 1 top-tube is an example of an eBike with a traditional double-diamond frame design. Top tube frames are more resilient than low step frames, and will be able to take more punishment over the long term without bending or cracking. This is the main reason that you almost always see double-diamond frames with a top tube on mountain bikes: with the level of impact that these bikes are expected to endure, it is very important to have a very stable frame that will roll with the punches.

Top-tube bikes can be made with lighter materials, thanks to the natural geometric resilience created by the triangular shape of the frame. As a result, top-tube bikes don’t need to be as reinforced as step-through bikes, which need more support to deal with common bumps and crashes. This factor is especially important if you want to make the leap towards frame materials like carbon fiber, as the sturdiness of the frame relies more on its construction as the materials get lighter. If you’re chasing the lightest bike possible, you’ll definitely want to get a top-tube bike. 

Top-tube bikes usually have a more aggressive riding stance, allowing you to cruise with less air resistance, pedal more efficiently, and go faster! Most road bikes, for example, will stick to a top-tube design and use drop bars to push that aggressive stance to its limit. Even if you don’t go for the most speed–oriented model you can find, a top-tube bike frame will generally go faster than a step-through.

Disadvantages of a top-tube frame

While a double-diamond frame may be the industry standard, there are some decided drawbacks that could push you towards a different frame style. First and foremost, the top-tube poses a challenge to those with limited mobility or clothing that isn’t quite your classic spandex. You have to be comfortable with swinging your leg over the top of the bike, something that can be challenging for older riders with poor flexibility or people dealing with chronic injuries.

It is very difficult to ride a top-tube bike wearing any sort of loose material, like a dress or harem pants, as it’s prone to getting stuck in the chain or hitching up awkwardly where it meets the frame itself. Most top-tube bike riders will need to invest in pant clips, or tie up their skirts in order to ride comfortably. If you’re looking for a bike that you can ride in whatever outfit, a top tube bike frame will be more limiting than you’re wanting.

The aggressive riding posture that’s normally seen with top-tube bike frames can also be an issue for those who are less experienced riding, or are looking for a more relaxed sitting posture. Top-tube frames lend themselves towards more efficient use of your pedal power, but holding yourself up in an aggressive posture requires practice and attention to proper form. If you don’t want to think about your technique as you ride, a cruiser-style, low-step bike will probably be your best bet.

Advantages of a step-through frame

If my description of the disadvantages of a top-tube frame had you second-guessing the road bike you were just eyeing, allow me to sing the praises of the step-through frame! It almost goes without saying, but it’s important to note that step-through bike frames are simply easier to get on and off of. If you struggle with hip mobility due to age or a health condition, skip the struggle and get a frame that will make for easy access. 

The main reason for inventing low step bike frames as a “women’s” model – accommodating dresses and skirts – holds up very well to this day. A low-step frame with a chain guard will let you ride in whatever clothing you find yourself in- perfect for everyday commuters or joyriding. 

Step-through bike frames are generally a more casual ride, and will lend themselves to more comfort-oriented models. Most low-step bike frames combine with a higher handlebar stem and swept-back handlebars in order to create a very upright position of the back. This enables you to go on longer rides in relative comfort compared to a top-tube frame with a more aggressive riding posture. This in turn provides increased visual awareness, making low step bikes a safer choice for busy urban environments.

Disadvantages of a Step-through Frame

The attention to comfort and ease that step-through frames facilitate is wonderful, but not without its own issues. The upright posture that usually comes with step-through brake frames will ultimately increase air resistance while you ride, meaning that you’re going to be slower on a low-step bike frame as compared to a top-tube with an aggressive posture. While a few miles an hour may not matter to more casual riders, speed demons take note!

Step-through bike frames also need to be reinforced more than their top-tube counterparts, since they lack the geometric stability that protects top-tube bikes from cracking under the pressure of a crash or heavy bump. As a result, they are usually heavier than top-tube bike frames, and may be an issue for those who need to carry their bike for any distance. To the same end, it’s more difficult to hold onto or brace a low-step frame against your body, since the absence of a top-tube removes the best handhold for proper lifting.

A small, but important point: step-through frames may not fit some car racks! If your rack relies on the bike having a top tube to attach correctly, you may need to purchase a top-tube adapter in order to hold your bike up. Even with a top-tube adapter, you may find that your rack isn’t as stable as it used to be. To be safe, you’ll probably want to make the switch to a platform-style rack, which can cost a pretty penny!

OK, Which One Should I Get?

At the end of the day, there’s no real wrong choice here. 

Bicycles are amazing inventions that will function for you beautifully regardless of what frame style you choose. That being said, your particular needs and wants may necessitate going one way or the other. Your frame style can mean the difference between an eBike you use some of the time and an eBike you use all the time, so this is not a decision to take lightly! Taking some time to think through the benefits and drawbacks of each frame style will allow you to come to a more informed decision on your next bike purchase, which will ultimately increase your satisfaction for years to come.

So, take your time. Try both styles of bike and see how it feels. Frame style is not the only factor to consider: you may love a top-tube road bike, but not drop bars. The folks at your local bike shop will be able to have a conversation with you to assess your needs and find the best fit for you, but armed with the knowledge from this article, I bet that you already have a good idea of which style will be the best for you!

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