How to make sure you buy the right-sized second-hand bike

Buying a second-hand bike that fits you properly is essential for both comfort and performance. A poorly sized bike can negatively impact your riding experience, from awkward handling to discomfort, injuries, or less cycling efficiency. For example, a bike that's too large may force you into an overly stretched position, making it harder to control the bike, while a frame that's too small can lead to cramped postures that strain your muscles and cause back pain.

Why bike sizing tables aren’t always reliable

Limitations of sizing tables

The most common way to determine bike size is by using sizing bike size charts, which provide recommendations based on your height and leg length. These tables simplify the process for bike sellers but can often lead to inaccurate results. In fact, they may fail to give the best advice in 40% of cases. About 20% of those cases will result in a less-than-ideal bike setup; adjustments can still be made by using less desirable components on the given bike. However, in the other 20%, the frame size recommended won’t allow you to achieve your ideal riding position, forcing you to compromise, which may increase the risk of discomfort, injuries, or a drop in performance.

Problems with standard recommendations

Bike sizing tables often provide a one-size-fits-all approach, which doesn’t account for individual differences in body proportions and riding preferences. This can lead to inaccurate sizing recommendations that might not suit your specific needs, resulting in an uncomfortable or inefficient riding position.

Stack and reach: the key to finding a bike that fits

Importance of stack and reach

To find a bike that fits you well, the two most important bike measurements are stack and reach, which dictate your handlebar position. Frame sizes are traditionally based on seat tube length, but the seat tube length isn’t as critical for choosing the right frame size. Most modern bikes allow for saddle height adjustments of over 20 centimeters, making it almost impossible to buy a bike that won’t accommodate your required saddle height. The real challenge is getting the handlebar position right, as there’s very little room for modification. The frame stack relates to the height of the handlebars, while reach determines the horizontal distance. These dimensions play a vital role in ensuring your riding position is comfortable and efficient.

Personalization of fit

Determining the correct stack and reach for you is complicated, which is why many bike brands stick to simple bike sizing charts. The ideal stack and reach are very personal and depend on factors like your body proportions, riding goals, and power output. For instance, a professional cyclist and a 65-year-old recreational rider who share the same height and leg length would need different frame geometries. The pro cyclist would require a smaller stack and longer reach for an aerodynamic, aggressive position, while the recreational cyclist would need a larger stack and shorter reach for more comfort. Similarly, two riders of the same height but with different leg lengths will have different frame needs. The rider with shorter legs but a longer torso will need a longer frame reach and therefore a larger frame size, compared to the rider with longer legs and the same height. This illustrates why leg-length-based sizing tables are unreliable.

Check your fit for any bike with an easy and free online tool

Using an online bike size tool

To make this complex process easier, Best Bike Advice offers a free online bike size tool that helps you check if a bike will fit your desired riding position.

Here’s how it works:

1. Enter your desired riding position: If you have a bike that fits you well, you can use its measurements as a reference. Otherwise, you can go to a bike fitting specialist or opt for the more affordable online bike fitting service offered by Best Bike Advice.
2. Enter the bike geometry: Enter three key bike geometry details—stack, reach, and seat tube length—of the second-hand bike you’re considering. These measurements are usually available online for most popular bike brands and models.
3. Calculate the setup: Click “Calculate Cockpit,” and the tool will generate a detailed setup guide, including the ideal saddle and cockpit adjustments to achieve your desired riding position on the bike you’re interested in.

By using this bike fit tool, you can ensure that your used-bike purchase will fit you perfectly, enhancing your cycling experience and performance.

So, which bikes fit you?

Finding the right-sized second-hand bike is crucial for both comfort and efficiency. While traditional sizing tables provide a starting point, they often fall short in delivering a perfect fit due to their generic nature. By focusing on key measurements like stack and reach, and utilizing tools such as the free online bike size tool from Best Bike Advice, you can achieve a more accurate fit. This will not only improve your riding comfort but also enhance your overall cycling experience. Take the time to assess your needs and use available resources to ensure your next bike is a perfect match for you.