Let’s talk about the difference between bike fit and bike design, and what each one is aimed at. Some of this will be obvious, but hopefully we can get at some things that people haven’t considered. It bears saying that I’ve worked in the custom bike space for nearly 15 years, and I do derive some part of my income from a custom builder, so impute whatever biases you think are appropriate.
So first, bike fit. What’s a bike fit for? Well, obviously to get you more comfortable and/or faster on your bike. Some people make a distinction between bike sizing and bike fitting. The former is figuring out which size bike you belong on, from a finite set of choices, the latter is figuring out what your actual, best position on a bike, any bike is. Many have been sized; fewer have been fitted.
If you have a good fit, you can take the numbers that describe it and adapt a stock size bike to them. That might entail a different stem length or angle. It might involve spacers under the stem. It might call for sliding your saddle forward or back on its rails. An adjusted saddle height. Basically any of the changeable aspects of a bike that comes with fixed measurements.
And, it’s tempting to say that, if you can achieve your fit numbers on a given bike, that bike is then a good bike for you, but here’s where we start to talk about bike design, because simply putting your hands, butt and feet in the right place in space doesn’t necessarily produce a good riding, comfortable, optimized bicycle.
When you work with a custom builder, they start with your contact points where they’re supposed to be. That part should be given. You don’t need a custom bike to achieve your fit. But a builder will then design what goes underneath to be the best it can be, and that can make a huge difference to your riding experience.
What does that mean in real terms?
Well, it means they can make the frame stiffer or more compliant, by making the frame more compact or more open in its angles, or it can be about using the right tubeset. It also means they can put you on a stem that is the right length to produce the right handling characteristics for you. It means they can match a fork rake to a headtube angle, again, to give you the kind of steering dynamic you like.
The tubeset is massively important. Build your frame with a tubeset that makes sense for your size and preferences means it’s the right weight, the right stiffness. These things are always meant to be in balance.
It is a common conception that steel frames are heavy. That conception comes from the fact that people building mass market steel frames use heavier tubing to account for the largest rider they think might reasonably buy the bike. For very large riders, those frames might not feel stiff. For very small riders, they do. That’s just science.
So, there are all these subtle things about bike design that amount to much more than achieving an optimal bike fit. Some of them are aesthetic. A designed bike will likely have more graceful lines than aproduction bike. A custom bike, a term I’m using interchangeably with ‘designed bike,’ should handle better, and it should weigh what it needs to weigh for the person riding it, not more or less.
There is a debate each person considering a custom bike should have with themselves about whether the sum of the benefits they can expect will justify the cost. On that score, I would only offer that most high-end production bikes, now, are pretty equivalent in cost to the custom builds out there. Whether you believe the clear optimization available in a custom bike is worth whatever the price difference, well that’s for you to decide.
Question: How do I find a bike fitter near me who I can trust? What should I be looking for and what questions should I be asking a potential fit expert who can help me sort this all out? For me to feel good about this, i need to trust the person I’m working with but I don’t know enough to evaluate potential fitters. Any advice would be great.
Bart, great questions. If I were looking for a local bike fitter, I’d start by asking other cyclists in my area who they’d worked with. If that didn’t turn up any leads, I’d do an internet search, and look for fitters who have certifications. There are a number of official fitting systems, each of which requires a certain amount of training for certification. Of those, I’d see who’d been doing it the longest. Finally, I’d trust myself. A fitter isn’t a wizard who looks at you and casts a fit spell. A bike fitting is a collaborative process in which you get to decide what’s working and what isn’t. Often times a fitter will put you in your most efficient pedaling position (or aerodynamic in some cases), and then it’s up to you to decide whether that’s a comfortable position for you to pedal in over a period of time. The final position may be a compromise between what looks optimal to the fitter, based on your stated goals, and how your body feels best. In the ideal scenario, they’re the same position, but as we get older, I think comfort trumps performance in most cases. Now that I’ve written this, perhaps it deserves its own post.