.png)
Total Fit Optimisation: The evolution and growing complexity of bike sizing, and a better way forward.
I still only have to tell about five people a year that the bike they have is the wrong size. It's a difficult conversation, but in their heart of hearts, the customer already knows it. It seems I'm merely there as an independent party to justify incoming purchases to their significant other. I'm happy to oblige. So it raises the question: why bother writing about the difficulties of bike sizing, if most people are finding their way to the correct size anyway?
Simply put, we're striving for something I call total fit optimisation. It used to be easy to fix a bike after the purchase with a different stem or crank, now with integrated cockpits and proprietary parts, it can cost you an extra $2500. The time to get it right is before you buy and understanding the true cost of the bike before buying.
Historically, bike sizing was based on "effective top tube" length and a seat height consideration. Frame sizes are now mainly understood using frame stack and reach. These data points allow for far more accuracy in sizing and geometry. If you look at a lot of geometry charts now, you'll notice the "old money" frame size is quite closely linked to frame stack, i.e., a size 56 will typically have a frame stack of 560mm to 565mm.
Having seen the benefits first hand a thousand times, I can tell you that when you buy a new bike, your starting point needs to be your ideal stack and reach, plus the component dimensions that connect you to the bike. You need to consider everything included (not just frame size) and get it as tailored to you as possible.
What really unlocks that next level of performance and comfort is considering the sum of all parts and how they create the optimal position. Without this, even a Pinarello Dogma is no help if your hips are just as closed off, your bars are too wide, and the discomfort these create remains. You're only ever going to get partway to achieving whatever you want the new bike to do better than your last (faster obviously).
This article will quickly cover helping new riders buy their first bike, then dive a bit deeper into my thoughts on TFO. This is geared (bike pun intended) at those of you who have been riding for a while and are starting to look for an upgrade, and those of you chasing optimal performance for racing.
From my own experience getting into riding (an absolutely daunting time and a fashion disaster, as it was for most of us), don't try to know everything all at once. Get off YouTube, get a bike, and enjoy riding it. Watch your speed, fitness, and happiness go up. A detailed understanding of frame stack and reach is probably not worth knowing yet. If you're really getting into your riding and looking to upgrade, it's essential.
If you are new to cycling and want to buy a road or gravel bike on the cheap, do this: take an accurate inseam measurement and use this data, as well as your height, to find the right starting point from the brands' sizing charts. This will get you on the right track. From here, you should get a proper fit straight away, learn how to use clip-in pedals, and get a sensible list of potential upgrades based on your goals and fit. The beauty of cycling lies in the many connections you make. Get into your local bike shop, make friends, go on a group ride, and believe in yourself!
If you are in the market for an upgrade, I implore you to dream about how much better an outcome you can achieve for the same cost with a pre-purchase fit. Here we consider the bike geometry, bar width, saddle selection, stem length, gearing, crank length, and purpose.
Blind bike buying is high-stakes online shoe shopping. I hate buying shoes online. I'm mostly a size 41, but sometimes a 42, sometimes a 40; it differs based on the brand, and it's no different with cycling. Take Canyon, for example. You're a medium in most brands, so you'd assume you'd be a medium in Canyon? Wrong. You're probably a small. Likewise, a Giant size ML is equivalent to most brands' size L.
This was really the purpose of frame stack and reach measurements: an evolution designed to ensure we were comparing specific data points, removing variables like seat tube angles. This ensured we could work from a set origin (the bottom bracket) and build the ideal contact point locations outwards from there. We're now progressing a bit further to handlebar stack and reach, or pad stack and reach for tri bikes. The outcome is accuracy and the removal of guesswork. Insurance for your new purchase.
Stack and reach are also great for helping us find the best bike within a certain category of rider. Most commonly, "the giraffe" body type: all legs, no body! Here we look for "aero" or race frames with a higher stack or a slightly shorter reach, keeping the stem length and the rider's weight distribution closer to the intended design.
A pre-purchase fit is not about me; what I love is getting you the best outcome. It's a little partnership. Together we will take all the positives from your previous setups, along with the issues, and turn them into a clear idea and data set to achieve Total Fit Optimisation. We can give you an ideal range to look within to ensure you have the perfect size and components.
This progresses slightly if you are chasing the ultimate performance gains in your next bike. Here it is even more about component optimisation within a frame size, and for TT/tri bikes, often ordering aftermarket handlebars to optimise for your position. When I was managing riders and race teams, I used to think of it like this: how can I turn the same effort into the best possible outcome? I had riders committed and training hard, so let's make the most of that and see if we can cross the line first. A waxed chain saves 4 W and increases drivetrain durability. What about gear ratios? Well, for lots of courses, 48/35 or 50/37 are simply not cutting it. I know it's not "bike fit", but to help riders be successful, we need to consider these items together.
There's buying the right size frame, but that's the easy bit after a while. It's really about making sure your money is optimised and weighing up all the components to get the best setup. Signing off, below is a few pages from "The Bicycle Racing Handbook" an awesome look back at how sizing and fitting was done (and standardised).
Comments