Happy belated new year, everyone. I suspect that many of you will be dreaming of warmer weather, planning rides, trips, events, races, and setting goals for this coming riding season. I’m getting pretty tired of riding the trainer, personally. I’d like to use the occasion of the new year to talk about the state of affairs in bike fitting.
The Rise of Fully-Integrated Cockpits
More precisely, I’d like to wade into a controversial topic as it relates to the intersection of industry trends, bike fit, and frame design. If you’re considering getting a new road or gravel bike in the coming year, you’ve probably noticed that much of the market’s offerings have moved toward a feature called fully-integrated cockpits.
That is: the brake hoses pass through the handlebar, stem, and then flow downward into the headset spacers, next to the steer tube, which, rather than being round, now has a cutout and is shaped like a D to allow for the passage of those hoses, as seen from above. The hoses then pass through the upper headset bearing, after which they part from each other. The front brake hose enters a port in the fork’s steer tube, on its way to the front brake mount. The rear brake hose enters the bike’s down tube, on its way to the non-driveside chainstay and the rear brake caliper.
Form, Function, and the Aesthetic Debate
If all of this sounds unfamiliar and complicated, if you feel that you’re without enough context to understand, I give you the license to consider yourself blessed with that ignorance. And so for the rest of you, I would propose that you have some pretty strong feelings about what the propagation of these integration systems means for the industry at large.
So, on the one hand, you have a bike which has a high level of, let’s say, aesthetic purity. These bike frames are sculpted into forms reminiscent of late twentieth century architecture, with smooth, swooping planes and angular folds. This is all done, ostensibly, in the service of the gods who govern aerodynamics. Bike manufacturers like to talk about the computational fluid dynamic processes they deploy in the pursuit of the system’s aerodynamic efficiency.
Aesthetics is always a matter of personal preference, of course, but it’s hard to say that these shapes aren’t pleasing to the eye, and that the frame’s omission of brake hoses works in service of that. Consumers have generally, thus far, spoken with their wallets, as they tend to do. Most people considering a road or gravel bike in the upper echelons of the pricing scale expect their bikes to come with systems to internally route the brake hoses.
Two Types of Integration
I should also mention then, that these systems fall into two sub-categories. In the first, the handlebar and stem are separate. The brake hoses (generally, although this is not always the case) run through the handlebar, then exit the handlebar through a port at the back of the handlebar into the cavity in the stem. The bar is held to the stem conventionally, with a stem-faceplate-clamping mechanism. The second category is much simpler in form, though it presents potentially more challenges for the bike fitter and the end user. The bar and stem are molded together in a unified piece of carbon fiber.
The Performance Factor: Why Are We Here?
But anyway, these are performance bikes we’re talking about, so we need to talk about the performance benefits of this feature, and more generally How We Got Here. Another way to ask the question is “what mechanisms are in place that put us in the situation in which we find ourselves?”
The UCI's Influence on Bike Design
One of those mechanisms is a rule held by bike racing’s world governing body, the Union Cicliste Internationale (hereafter referred to as the UCI), regarding equipment use. I’ll paraphrase to keep us out of the nettle-filled gutter of jargon, but basically, the rule goes that equipment utilized by professional teams should be made available for sale to the general public. This rule seeks to quote-unquote level the playing field among the professional teams.
A cynical view of this rule is that it is a mechanism feeding the consumer desire aspect in this industry. The logic (or, un-logic, if you wish), is that all industry requires constant cycles of production and consumption in order to continue to survive, and the desire to mimic our sports heroes feeds into that cycle.
But then again, it’s hard to imagine a modern-day peloton rolling around on the equipment of the last century. I’m of the opinion that the vast majority of the technological progress made in the bicycle industry in the last, say, 25 years has yielded a net benefit to the end-user. I’m thinking about things like 30-ish millimeter tires set up tubeless at much lower pressures than we’re used to. I’m thinking about saddles with deep cutouts and structures designed to mirror the skeletal shape of the pelvis.
Aerodynamics and the Pursuit of Speed
Moneyball cycling has given us the lodestar, the new true-north toward which we should steer our ships, which is the holy holy pursuit of perfect aerodynamic performance. And of course, because everything is quantifiable, here’s your new target: Cda. Cda (coefficient of aerodynamic drag) is a measure of the energy required to push your body and the machine into the wind-environment. Contemporary science suggests, as a general rule, that aerodynamic drag takes over as half of your body’s energy output requirement at 15 miles per hour, scaling exponentially toward an asymptote of 100% the faster you move. So aerodynamic efficiency should be of utmost importance for those of us looking to ride efficiently in the twenty-ish miles per hour range. Given that the professional peloton moves around the course at 29 miles an hour or faster, it should then be even more important still.
Does Cable Integration Really Save Watts?
One of the things that a fully-integrated handlebar and stem achieves through hiding its brake cables is the reduction of a non-trivial amount of aerodynamic disruption (or, turbulence), thus improving the aerodynamic performance of the rider-on-bike system. Well, is it non-trivial? Some researchers have done work in this space, and the consensus seems to be that a standard length of exposed cable housing will cost the rider between 1 and 5 watts of energy to push the bike the same speed in the wind at normal racing speeds, all other things being equal.
So I think we can say, generally, that for the majority of the cycling-consumer bracket, this amount of wattage-savings is actually trivial, but should we assume that that’s true for riders whose paychecks are won and lost at the white finishing stripe on the road? Well it either is or it isn’t, but we should probably also assume that the Directors Sportif and the science departments behind professional cycling teams have had their share of the cool aid. No one wants to have lost a bike race by the width of a tire.
So, given that the brands that manufacture for the teams are bound to producing machines for the masses that nevertheless must perform at the highest end of performance, well then, this is how we get to fully integrated stem and handlebar systems. We should also recognize that these systems often fall into a one-to-one proprietary system unique to that brand/manufacturer (although some efforts have been made to coalesce toward an industry standard: see ENVE and Chris King with their In-route system).
How This Affects Bike Fit
How this all relates to bike fit might be obvious to you, but if it's not, I’ll spell it out. The selection of a handlebar width and a stem length is of significant concern for riders choosing new bikes, solving problems on their current bikes, or for riders who are looking to approach their bike fit holistically. Many riders come in with bikes that fit them well, but moving to a narrower or wider bar, or a shorter or longer stem is a linchpin of the bike fitting them as close to perfectly as functionally possible.
In my experience bike fit has been, for consumers, an endpoint at a series of problem solving decisions. That is, riders seek out bike fitters when they are unable to resolve their bike-body problems on their own through trial and error. In that context, working with riders who come into the fit studio on bikes that have integrated bar-stem systems, and which route the brake hoses internally present a fairly significant challenge. What is to be done in a scenario where I find it necessary to shorten a rider’s stem by 20mm, or to move to a narrower or wider handlebar than the bike currently has? What are the ramifications to rider comfort when we are forced into a narrower bracket of product solutions due to the proprietary nature of these systems?
The Challenge for Mechanics and Fitters
There is a significant amount of work in store for a mechanic charged with modifying a stem and handlebar to resolve fit related problems on one of these fully-integrated bikes, post first assembly. The mechanic will remove the brake hoses from the levers, cut the olive and barb off of the end of the brake hoses, and then gently remove the bar/stem from the steer tube. The installation of the new bar/stem is orders of magnitude more sophisticated. The mechanic will need to reverse this operation, but guiding the brake hoses through the narrow openings of the bar and stem requires utmost patience, and an abundance of time, even if he or she is using guides to help pilot the direction of the hoses. In some cases, the bar width and stem length are correct, but the stem needs to come down on the spacer stack. This may still involve cutting the brake hoses, and will usually also involve cutting the steer tube, in which case the bar/stem assembly will need to come off. In almost every one of these services, the brakes will also need to be bled. So, think anywhere between and hour and a half and three hours of labor.
The Cost of Complexity
And with all of the extra time comes added cost. I’m not oblivious to the fact that a bike fit is a premium service (although one I still think has a massive amount of value), so when customers balk at the prospect of doubling the cost of the service to deliver the end goal of that service, I totally understand the hesitation.
The Shift Toward a Fit-First Approach
As customers start to become wise to the potential pitfalls of all of the points outlined above, I’ve found that they’re moving toward a fit-first approach. This is uncategorically a good trend. Many riders who are looking to buy bikes with these integrated cockpits are wary of getting that decision wrong on the front end, so they seek out professionals like me to help guide them toward the right equipment. The benefit is usually that, not only are we able to resolve the question of “which stem and bar dimensions should I be on,” but it also usually helps us resolve more fundamental problems in a rider’s position. These include, but are not limited to, saddle instability, saddle asymmetric pressure, saddle-soft tissue discomfort, knee alignment and foot stability, and posture concerns. How these different elements all affect each other make it hard to assess any of them in isolation, and I guess this is one of the main things I want people to understand about what I do as a bike fitter. I need to not only press into the minutia of how the interlocking parts of the body work together, but also to scale out to the macro-view of the system as a whole system of systems. In order to adequately assess how a rider interfaces the front end of the bike, I need to understand how the rider interfaces the bike at the saddle and the pedals, how capable they are of rotating their pelvis forward and extending their spine.
The Irony of Integration
The irony of this move toward integration is that, given that the stakes of getting it right on the front end are much higher, my job has counterintuitively gotten a little bit easier. For riders looking for their new bike, we can spend time in the fit session on the dynamic fit bike (a modular bike that allows me to quickly change and adjust any of the fit-related components), working from a blank-slate, or with the rough outline of a bike that they may want to purchase. We can then maximize time in that session developing new strategies for setting good habits in pedaling and holding healthy bike posture, for giving a rider time to quiet their central nervous system to outside stimuli and focus on feeling the dynamics of the bike-body interface, and for talking about things the rider can do off the bike to promote good on-bike strength, stability, and symmetry.
Then when the new bike comes in, the bar width and stem length is already sorted out. The mechanics can assemble the bike once, after which I will typically spend 15 to 30 minutes with the rider making micro-level adjustments of the saddle angle, saddle height, and brake hood position.
Welcome to the future. Enjoy your new bike.