Numbers don’t lie but there’s more to a bike fitting than just data.
A bike that fits you and your riding style is like wearing custom-made clothes…only better. Your bike — the one that’s sized for you — improves cycling performance since no effort is wasted compensating for an ill-fitting bike. A bike that fits can also spare you from injury resulting from poor biomechanics when riding. Stock bikes are often the manufacturer’s calculated estimate at a bike size for an averaged demographic. Custom bikes are crafted according to the rider’s unique measurements, which take into consideration the rider’s own physiology and even prior injuries.
So how do you get these singular numbers? A bike fitting done by an expert will yield data that can either be matched closely to an existing stock bike, or can be input into a custom frame manufacturer’s design program to produce a frame that’s been optimised for the rider. Many bike fitting systems exist — some are owned by bike brands, others are partners in service to a particular brand — both of which tow a bit of bias in their wake so it’s wise to investigate and search out experience over the system used. You can also DIY your own bike fit if you have a general idea of what’s covered in a bike fitting. Decathlon’s in-store teams are trained to perform visual bike fits, and for a more in-depth fit, they will recommend going to a specialist.
How you like sit on your bike will factor into your fitting measurements. Are you more of a leisure or endurance rider? You may prefer a slightly more relaxed or upright position on your bike. Or are you a triathlete with a specific purpose for your bike? Then you may have a precise position you want to achieve, which is why you should know about…
Two of the most fundamental measurements in nearly every bike fitting system are reach and stack. Think of an imaginary line drawn vertically from the centre of the bottom bracket upward. Now connect that vertical line with a horizontal line that starts at the centre of the headtube. The distance in centimetres of that horizontal line is the frame’s “reach”. Now think of an imaginary line drawn horizontally from the centre of the bottom bracket toward the fork. Now connect that horizontal line with an imaginary vertical line that starts at the centre of the headtube. The distance in centimetres of that vertical line is the “stack”.
Since no two manufacturers’ frames are created equally, your reach and stack will show you which standardised frame sizes would best fit you. Reach and stack will also provide the foundation for a custom frame manufacturer to start designing your frame.
How you interact with the saddle, pedals, and handlebars have a huge impact on your comfort on the bike. A bike fitting will address these three points of contact to arrive at optimal comfort for the bike’s and rider’s intended purpose.
Many bike shops will offer bike fitting to better serve their customers. Decathlon team members cover: posture; setup and selection of shoes and cleats; frame size; saddle height and position; handlebar height; and selection of recommended handlebars, saddle, and stem.
A Bridgtown Cycles bike fit is a business unto itself, simply called “Bike-fit”, and has detailed its process on its website http://www.bike-fit.co.uk.
Beyond the basics of a bike fitting are technique, process, and pricing, which can vary greatly among service providers. Experience, referrals, and testimonials can also matter so it may help to take some time to research what’s the best bike fitting for you. While it’s true that numbers don’t lie, a bike fitting that’s done well will also reveal a few more truths about you too.