Size matters – achieve harmony between rider and machine

Size matters! How to achieve harmony between rider and machine

Get a frame that matches your frame

Every bike – like every body shape – is different. Even road bikes with the same frame size can have wildly different characteristics, rider position and geometry. With any type of bike – road, mountain or hybrid – the length of down tube, top tube, crank, plus the handlebar shape and wheel diameter all make a difference to how you interact with a bike.

The top tip for choosing the right size of bike for you is to try before you buy. At Bikes Direct, we’re always happy to let you take any of our bikes for a spin to help you make the right decision. We’ll give you good advice on how one varies from another. In a few minutes, you’ll get a better understanding of why some bikes feel right the moment you get on them. And why others might not be right for you.

Measure for measure

The simplest way we make sure your bike measures up correctly is the length of your inside leg. For a horizontal top tube (from handle bar to saddle post), we use the formula: inside leg measurement (cm) x 0.69. Then we round up or down to the nearest frame size option. The formula is slightly different if the tube is sloping: inside leg measurement (cm) x 0.64. Again, we round up or down. For horizontal and sloping tubes, we recommend the smaller option if you are in between sizes.

So you’ve chosen the right frame size. What next?

Now it’s time to make your bike personal to you. While there’s a degree of individual preference, it’s best to start from the ground up. Here are five areas that will make a big difference to your riding comfort and efficiency:

  • Pedals and/or cleats – the power comes from here, so if you’ve opted for clip-in pedals and shoes, the position and angle of the cleats is a good starting point.
  • Saddle post height – it sounds obvious, but it’s surprising how many people get this wrong. One of the best tips is when you’re sat in the saddle and the pedal is furthest away, you should be able to put your heel flat on the pedal with your leg fully extended. This will mean that whether you’re clipped in or on flat pedals, your knee should always be slightly bent. It may take a few adjustments to get right, so we’d recommend marking your seat post with some tape. This makes it easier to adjust a few millimetres up and down.
  • Saddle angle and the fore/aft – again, it’s worth noting the saddle angle (by taking a photo). You can also mark the fore/aft position on the saddle rails for future reference. This will help you make micro-adjustments in the future.
  • Handlebar height – there will usually be spacers on the headset tube. The lower the handlebar, the racier the ride position. However, it can put pressure on your lower back if your handlebars are too low.
  • Stem angle and length – last but not least, getting the correct length of the stem can increase comfort. And from a safety point of view, you don’t want to be reaching too far for the brakes and gears.

At Bikes Direct, we can help you achieve exactly the right combination of adjustments. Of course, you could take it to the next level with a custom fit.

 Why choose a custom fit?

There are lots of reasons why it makes sense to get the help of a bike-fitting professional. These include avoiding exacerbating an old injury or gradually causing new issues. The common signs are pain in the shoulders, neck, lower back and wrists. On top of added comfort and efficiency, an expertly fitted bike will help you achieve your fitness goals and challenge yourself to go further and faster.

And consider the money you’ve just spent – hundreds (possibly thousands) of pounds on a new bike and kit. With the advice of an expert, you’ll get the most out of your investment.

Barrie Robinson

With that in mind, we spoke to Barrie Robinson – a passionate road, mountain and indoor cyclist who runs PedalActive in Ashtead, Surrey.



What are the mistakes often made when setting up a ride position?

BR: The most common are the saddle angle – both pointing too far down or up. Then there’s saddle height – the fore and aft position. Especially if you’re new to them, problems with cleat position are common. Lastly, making sure that brake levers are in the right position can make a big difference.

How long does a fitting take?

BR: About an hour, as it’s important to get to know about the person and what kind of riding they’ll be doing. I’m always keen to know why they think they need a fit. And what they intend to be doing from time trials to sportives to general riding. We’ll talk through medical history, discuss any previous sports injuries and get them moving so I can see if there are any restrictions. It’s onto the bike next, to see their riding style and how it can be improved. The first thing I’ll look at is the contact with the bike –starting with the pedals and cleats.

What’s your measure of success?

BR: Feedback is a key part of the fitting. Most people are happy with their new bike set-up and feel the benefit almost immediately. Only a few require some follow-up with a more scientific bike fit. This takes a bit more time and adds to the cost, because we use specialist equipment for an Apex fit. As part of this fitting, we make adjustments which take heart rate into account. However, in my experience, the additional adjustments from the initial fit are miniscule.

To learn more about bike fitting or to contact Barrie at PedalActive, visit

For free, friendly and impartial advice that you can trust, come and visit us from Friday–Monday at Bikes Direct in Dorking – see directions.


By Glenn Sturgess