Yelling at the Clouds

Why you sweat on a bicycle, and how the North American bike industry has ensured bicycles do not become a main form of transportation

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Sweating while biking is not a new complaint. If you talk to most people about why they don’t ride a bike to work or school, you will find that arriving to work all sweaty and gross is one of the main complaints. Taking a step back and analyzing this complaint objectively is interesting, because in theory this should not be the case.

Bicycles are one of the most efficient ways to get around. In fact, it is more efficient than walking with biking being 5 times more efficient on a per distance basis. If this is the case, why do people associate a bike commute with sweating? If you can walk for 50 minutes without getting all sweaty and gross, a 50–minute bike ride should be a piece of cake.

It is because there are three pillars you and your bike need to abide by to ensure your sweating is kept to a minimum. The pillars are as follows:

1. Get low gears, even to climb the most baby of hills
2. Stop riding around with a pack strapped to your back  
3. Ride within your comfort zone, in a comfortable position and at a sustainable pace

What is so interesting about these simple tips is that most bikes the bicycle industry sells violate at least one of these pillars. This has a ripple effect of consequences, the most notable of which is that you continue to think that you will get all sweaty on your way to work. This maintains the status quo, at least for us in North America, that bikes are for fitness, not transportation. With the climate crisis staring at us with its fiery eyes, I can surely say this isn’t good for all of us.

1. Get low gears, even to climb the most baby of hills

Low gears matter to making a bike commute bearable, especially if there are hills (or in SF, mountains) between you and your destination. How much they matter can be hard to explain. Gearing on bicycles is usually spoken about in terms of gear inches, and most bikes will come with a range of 90 gear inches (your hardest gear) to 25 gear inches (your easiest gear). The low end is what I am most interested in for this analysis, because that will dictate how slowly you can pedal your bike up a hill without falling over. Even just dropping your lowest gear by 10 gear inches can more than half your power output on steep hills. Let me explain.

Figure 1 plots the minimum power required to move your bike up a hill as a function of % grade of hill for a variety of gear inches. The minimum gear inch on your bike will dictate how fast (or slow) you can pedal yourself up a hill comfortably. Remember, higher is harder to turn, which is why the 30 gear inch line sits above the 25 gear inch line.

The most apparent feature of this plot is that the lines are diverging. As the riding gets steeper, a high geared bike will force you to pedal significantly harder than a low geared bike for not much gain in speed. While going up a 15% grade a bike with 14 gear inches will need a minimum of 222W; a bike with 25 gear inches will need a minimum of 398W – almost double the power.

I want to stress how small of a change this could be on your bike. 10 measly gear inches can be the difference between you being sweaty at work or arriving comfortably and ready to tackle the day. Unfortunately, most bikes sold by the larger manufacturers tend to come over geared.

My first bike was a Specialized Sirrus (a sorry excuse for a bicycle), sold to me as a way to commute from Oakland to Berkeley. It had a minimum gear inch of 25. Most bikes have gearing that is carried over from professional racing, with my bike being no exception. The Trek Domane SLR, your standard Tour de France racin’, back bustin’, power meter measurin’ bike, has a minimum gear inch of 26, for example. Why should my transportation bicycle be as hard to pedal as a full-on carbon, aero race bike?

Having tall gears on your bicycle is the equivalent of being forced to run up a hill and asking why you are all sweaty. If you find yourself huffing up hills, consider a smaller chain ring. It could literally half your power output on your commute.

2. Stop riding around with a pack strapped to your back

This one should be pretty easy to understand if you’ve ever had to walk somewhere on a really hot day with a backpack on. A backpack, though a pretty efficient way to carry your stuff around, does not offer much in the way of a crossflow for your back, leading to the infamous back-sweat stain you see all over tourists backs on a hot NYC day. Aside from the sweat, a backpack weighs on your shoulders and is pretty uncomfortable for long stretches of riding. I think it is best to make your bike bear that weight, opening your back to the breeze and freeing your joints.

The simplest way to carry your backpack (or any other thing on your bike) is with a front rack and basket. Having your stuff in the front allows you to keep an eye on it as you pedal, and using a basket allows your cargo to be flexible in size – you can throw your backpack in there, some groceries, or strap a plank of wood to it when it doesn’t fit. Unfortunately, not all bikes can accept this storage solution, mostly because of the recent adoption of carbon forks, even on the most pedestrian of bicycles.

I’m not a carbon expert. I won’t say it’s this fragile, delicate material that will break when you look at it. From my days making carbon bicycles, however, I do know that carbon’s strength is not intrinsic like steel’s. It is directional – a product of it being an anisotropic material. This means that while the fork may be strong in the direction of normal riding, it can be weak in others, like in the direction of a load that a heavy basket may place on the fork. As a result, unless your carbon fork was explicitly designed to handle a front rack and basket, it is generally recommended that you don’t put a basket on the front of your bike. My Specialized Sirrus, the bike I bought for transportation, has a carbon fork not designed for a front rack.

There are other solutions to this problem, of course. If the rest of your bike is not carbon you could put a rear rack and basket on, but that has the problem of peace of mind. You could purchase panniers or frame bags, but then you lose the flexibility of the “unknown cargo” you may have to carry that doesn’t fit in the bags. Plus, you have to buy all new, and probably expensive, bicycle bags, when the backpack you have is just fine.

Not being able to put a front basket on your normal bike, specifically because of a frame material that is again a carry-over from racing technology, feels like a gross oversight. In my opinion, any bike that is to be used for transportation that does not have a basket pre-installed from the factory feels like an oversight. And again, is an example of how the bike industry, by focusing on racing, holds itself back from being a form of transportation.

If you find your back all sweaty because of your backpack, consider some kind of rack to have your bike work for you (if your bike will allow you).

3. Ride within your comfort zone, in a comfortable position and at a sustainable pace

Even if you do the above two things, you can still sweat if your bike does not allow you to do this one right. This one seems like it should be your own fault if you aren’t already doing it. “Sustainable pace” – don’t you hold the keys to your own pedal cadence? It is true that you can choose how fast you go, but the position you are in on your bicycle can greatly affect how fast you choose to move yourself.

Bikes the bike industry likes to sell and promote typically feature aggressive riding positions – ones in which you are more leaned forward, with weight on your hands. Another carry-over from racing, the general talking points a salesperson might tell you is this position gets you in a more aerodynamic position and allows you to engage your glutes on a pedal stroke. At least that is what they told me when I was buying my Specialized Sirrus after I told them the position felt a little forward. Taken at face value, riding in a forward position should be easier and more efficient than riding in an upright position.

I don’t think it’s as simple as that. In order to sit on your bicycle in a leaned over position, even one most road cyclists would consider “upright,” you need to have significant core strength and back flexibility. It takes effort to hold yourself in these back-breaking positions, undoing all of the pedaling gains you get sitting in these uncomfortable positions.

The second problem is psychological – I believe that riding in this more aero and “efficient” position tricks you into pedaling harder than you probably would have. This is purely my opinion, but I have noticed myself pedaling faster and zipping through traffic more when I ride a bike where I am more leaned over. The key here is that the uncomfortable position keeps your focus on the riding, on the pedaling.

Consider the polar opposite – a bike where you are sitting closer to the position you normally have sitting in a chair. You are less aerodynamic and less able to engage your glute muscles, but you also have a clearer view of the traffic in front of you. You stop constantly changing your back shape to stretch it out as you ride. You start to forget about your pedal cadence entirely and plod along however fast you want.

With the increased visibility and lack of discomfort, you focus more on what is happening around you. You start to notice that house with oranges growing in the front, or the birds chirping at the beginning of the day. The riding, being so simple and comfortable, is forgotten. That is when you have achieved it. When you expend about as much effort biking as you do when walking. Riding in a comfortable position and at a sustainable pace is how I can bike 8 miles one way to work, over the SF mountains and through the sunny flats of Palo Alto, usually without a single drop of sweat.

It’s important to me that people see riding this way. Riding can be a physical, exhilarating activity, and the bike industry loves to sell bikes that fulfill that purpose. But riding can also be a calm and leisurely way to get yourself from A to B, which is mostly a hidden perspective in the bike industry. By keeping this away from the public eyes, the bike industry ensures that people cannot see bicycles as a normal means of transportation – it remains something only people who don spandex could do – and holds us in the car dominated world we live in today. I hope we can change that perspective sooner rather than later.

If you find yourself racing to work, sit more upright and relax. We’re supposed to be walking, not running, to work.