If you observe the road bikes of professional cyclists, you’ll quickly notice a trend – many pros are riding a frame that’s one or two sizes smaller than what a bike fit expert would recommend to a regular person.
If a recreational cyclist was caught on a small frame, most people would quickly conclude that the person in question is simply ignorant, but when the pros do it, we ask why in an attempt to reveal a big mystery.
So, why do pro cyclists ride small frames?
Pro cyclists choose smaller frames to acquire a more aerodynamic position thanks to the lower head tube. Also, compact frames are more agile, easier to manipulate, and have a shorter wheelbase resulting in more stability when cornering.
The Benefits of a Smaller Frame
At first glance, a small frame may look like a bad choice and a spectacular way to put your body in a disadvantageous position, but there are many benefits to this strategy. Below, I am listing all that I can think of at the moment:
1. Greater Drop
Smaller frames come with a lower head tube resulting in shorter stack height.
What is stack height? Stack height is the vertical distance between the bottom bracket of the bicycle and the top of the head tube.
The lower stack height results in a greater drop from the saddle to the bars once the rider sets the seat post at the setting required for comfortable pedaling (image 2). As a result, the bikes provides a more aerodynamic position.
(Wheelbase – the distance between the front and rear wheel axle.)
A shorter wheelbase offers more maneuverability. A comparison between a bus and a car illustrates this effect perfectly. Buses have a very long wheelbase whereas cars have a short one allowing them not only to pass through tighter corners but to do so fast.
Of course, the difference in terms of wheelbase between a normal size frame and a smaller one isn’t nearly as great.
However, when a rider switches from a small frame to a bigger one, it’s not uncommon to feel like you’ve lost a lot of the bicycle’s maneuverability.
Even 2cm can create the perception that you’re riding a bicycle with a severely reduced cornering ability.
In general, longer wheelbase bicycles are saved for touring and commuting because the extra length makes the frame more stable and comfortable during long rides.
Road bikes and mountain bikes are not in that category because they’re designed to be ridden more aggressively.
Therefore, by choosing to ride a smaller size frame, the riders are reducing the wheelbase one more time in comparison to long-distance “luggage” bicycles.
Shorter Head Tube
Naturally, bicycles of smaller size have shorter head tubes too. The short head tube lowers the handlebars and puts the rider into a more aggressive position.
Shorter Top Tube = Longer Stem
To compensate for the shorter top tubes on smaller frames, cyclists use longer stems.
The longer stem creates a larger turning radius and slows down the steering of the bicycle, albeit minimally.
Normally, this would be considered a downside when riding a mountain bike, but road bikes operate differently due to the terrain that they are used on.
The slowed-down steering is expected to feel less “twitchy” – a bonus when riding at high speeds over a smooth road surrounded by a large group of other cyclists.
Having said that, the primary reason why longer stems are found on smaller size frames is that this is the only way to create the reach (image 1) that the body of the cyclist needs.
Note: Some people argue that the effect of long stems on the steering isn’t significant as long as the stem length is within reason. Also, the body quickly adapts to the new stem length after a couple of practice sessions.
Lower Weight (Potential benefit)
Shorter frames require less material and are therefore lighter than their bigger brothers.
This property may not be seen as a bonus because any bike that ends up in the hands of a professional road cyclist is light by default…sometimes so light that additional weight is added to satisfy the regulations.
Nonetheless, the weight savings could still be seen as a bonus in lower cycling divisions where people do not have the pleasure of riding ultra-light bicycles.
Another plus is that the savings allow engineers to redistribute the extra weight needed to fit within the rules towards the bottom rack. This practice effectively reduces the bike’s center of mass.
Note: The longer seat posts and stems required by the smaller frames negate some of the weight savings.
Smaller frames come with shorter tubes and subsequently less flex and twisting. This characteristic makes them more responsive and agile in comparison to the bigger ones. The loss of energy is minimized too.
Some people consider this benefit more of a placebo than reality as it’s highly debatable whether the end-user can feel the difference.
Longer Seat post
A smaller frame necessitates the use of a longer seat post which some people deem beneficial because it offers some flex and “cushioning” for the rider with a limited vibration transfer to the frame.
A Way To Customize Commercial Frames
In ideal situations, all cyclists would be riding custom made frames and components. However, this scenario doesn’t enroll all that frequently. Many pros compete on commercially available frames.
And since the “optimal” frames often come with head tubes that are longer and subsequently taller than what a pro cyclist may prefer, a smaller frame is selected to get a better “aerodynamic fit” without ordering a custom package.
A smaller frame gives you more room to make adjustments by swapping out components whereas a large one is pretty much set.
For example, it’s not uncommon for professionals to rely on many stems sometimes varying only by a couple of millimeters. Depending on the terrain, a different stem is deployed.
Another aspect that’s subject to adjustment would be the saddle. Many pro cyclists have long femurs and thus need room and height to pedal efficiently. To make up for the small frame, some cyclists use a saddle with a great setback allowing them to push the saddle back significantly.
Lower Top Tube = Less Contact With The Frame
The lower top tube found on smaller frames should at least in theory lower the risk of frame contact injuries because it’s further away from the body.
However, due to the chaotic nature of collisions, it’s difficult to know the extent of injury prevention resulting from this characteristic.
Economical Reasons Behind Smaller Frames
There’s a business incentive behind the use of smaller frames too. It’s often cheaper to produce small, stiffer frames and then balance out the fit with components (saddles, seat posts, stems, handlebars) than to manufacture lots of frames tailored to everyone’s specific needs.
How Small Are The Frames of Pro Cyclists
Many pros run the smallest frame that they can fit on. Most of the time, that amounts to a frame that’s 2-4cm smaller than what the original bike fit instructions say.
Below you will find a table listing the heights of pro cyclists and the frames they ride.
Note: The actual frame size may change if the rider decides to experiment with a new frame.
The table reveals a great deal of variety. Some riders ride a frame that’s truly small while others are very close to the recommended size for their height.
Observation: Some Bicycle Shops Are Pushing Bigger Frames
It’s my observation that some bicycle shops are actively pushing bigger frames and wheels (in case of mountain bikes) on people.
This may be just a local trend, but I often see cyclists with new bicycles built on massive frames. More often than not those men have purchased whatever the bicycle shop owners have recommended to them.
I see two possible reasons for this scenario:
- Bigger frames with more upright geometry are more beginner-friendly. In consequence, the customer, who in most cases is an untrained beginner, is less likely to return the bicycle due to discomfort.
- Some shops have many big frames in stock and are trying to get rid of them.
The same applies to mountain bikes. When I was buying mine, the shop owner did his best to convince me to buy a 29-er with the biggest frame that I could fit on.
However, since I was planning do to some tricks (e.g., bunny hops), I purposefully went with 27.5-inch wheels and a smaller frame. I don’t regret the decision.
Frequently Asked Questions
Are smaller frames uncomfortable?
They could be if you don’t have the necessary flexibility, and the position is new for you.
Professionals don’t have that problem because they’ve been spending a great deal of time riding since a very young age. Their bodies and central nervous systems have already adapted to cycling in the “ultra-aero” position.
As with any sport, overuse injuries do happen, but at the end of the day, professional sports are focused on performance rather than comfort.
Also, racing road bikes aren’t designed for leisure. Their purpose is to be fast and efficient on the road.
Conversely, touring bikes operate on the opposite end of the spectrum – they come with a longer wheelbase and a more upright position facilitating prolonged hours of cycling.
Why didn’t cyclists ride smaller frames in the past? What’s behind the new trend?
One of the main reasons for riding a big frame in the past were the conditions of the roads and the greater distances that had to be covered.
The riders didn’t have the luxury of cycling only on smooth asphalt as a lot of the infrastructure was gravel. Hence why at the time, they were riding large “calm” frames with very little of the seat post showing. In the 70s, this began to change gradually.
Ultimately, the main driving factor behind the revolution was the pursuit of faster times.
Should recreational riders mimic the pros?
Professionals do everything in their power to optimize every angle of their performance. This is their highest priority. But ordinary people who aren’t even racing don’t have the same incentive to sacrifice comfort for performance.
Why put yourself in an unpleasant position if you’re not even competing?
In most cases, it would be wiser to get a fitting that’s more appropriate for your needs. A bicycle that puts you in a “pro position” may look cool, but if you don’t have the flexibility and the time to adapt, then the neck and back strain could discourage you from riding as much as you would with a more “amateur” machine.
Nonetheless, it’s very realistic to adapt and ride a small frame just like the pros if that’s what you want. You just have to be patient.
If you have pre-existing conditions, you should ask yourself if the exercise is worth the effort.
Is it worth paying USD 100+ for a professional bike fit?
If you take your cycling seriously, have the money, and trust the experts, then the answer is yes. After all, a good fit can boost your performance while simultaneously lowering the stress on your joints.
If you don’t want to spend the extra money and/or don’t trust the expertise that you could receive, you could go by online calculators as they produce surprisingly decent results.
Note: Some bike shops may tell you that you need a certain size just to sell you a frame or a bike that they have in stock even though it’s not the best option for you and your style of riding.