Even if you ride on flat asphalt surfaces with your road bike, a mismatch may cause discomfort and, worse, injuries. It is crucial to choose a well-fit vehicle and make some more tweaks for the best performance and efficiency.
These motivations prompted us to compile a road bike frame size chart and in-depth measurement instructions. Bicycle shopping has never been easy, but we have your back now!
Table of Contents
Road Bike Size: What Suits You Best?
Measure Your Height And Leg Inseam
Most people know their height well or at least have no trouble measuring it. Hence, you guys refer to this indicator and decide on the bike range. As experienced cyclists, we recommend using an inseam as it is much more accurate.
Doing the leg measurement at home is a piece of cake. Follow our step-by-step tutorial:
- Prepare a hardcover book with a pencil.
- Put on your cycling shoes and stand leaning against the wall. Keep your feet slightly apart.
- Clip the book between your legs and raise it slowly until its spine touches your crotch.
- Mark where the top of the spine meets the wall and then measure from this point to the ground. The obtained distance is your inseam length.
After you get all the figures, calculate the bike size following this formula:
Inseam measurement (cm) x 0.67
Now, compare your result with the table below.
Road Bike Size By Height
|Height||Inside Leg||Recommend Size|
|4’10’’ – 5’0’’||147 – 152||26’’||66||47, 48cm (Extra extra small)|
|5’0’’ – 5’3’’||152 – 160||27’’||69||49, 50cm (Extra Small)|
|5’3’’ – 5’7’’||160 – 170||28’’||71||51, 52, 53cm (Small)|
|5’7’’ – 5’9’’||170 – 175||30’’||76||54, 55cm (Medium)|
|5’9’’ – 5’11’’||175 – 180||31’’||79||56, 57, 58cm (Medium, Large)|
|5’11’’ – 6’2’’||180 – 188||32’’||81||59, 60cm (Large)|
|6’2’’ – 6’5’’||188 – 196||34’’||86||60, 61, 62cm (Extra large)|
|> 6’5’’||> 196||36’’||91||62, 63cm (Extra extra large)|
|Height||Inseam Size||Recommend Size|
|4’10’’ – 5’1’’||147 – 155||26’’||66||44, 45, 46cm (Extra extra Small)|
|5’1’’ – 5’3’’||155 – 160||27’’||69||47, 48, 49cm (Extra Small)|
|5’3’’ – 5’5’’||160 – 165||28’’||71||50, 51, 52cm (Small)|
|5’5’’ – 5’8’’||165 – 172||30’’||76||53, 54, 55cm (Medium)|
|> 5’8’’||> 172||31’’||79||56, 57cm(Large)|
Manufacturers of kid bikes often approach sizing by wheel size rather than a frame. You can turn to the bike size calculator below before going to the store.
Note that the adult bike sizing may sometimes work well with some well-developed children, but their bicycles had better be equipped with under 26-inch wheels.
|Approx Age||Height||Inseam Size (in)||Size Wheel|
|2-3||2’10’’ – 3’4’’||14’’ – 17’’||12’’|
|3-4||3’1’’ – 3’7’’||16’’ – 20’’||14’’|
|4-5||3’7’’ – 4’0’’||18’’ – 22’’||16’’|
|5-8||3’9’’ – 4’5’’||22 – 25’’||18 – 20’’|
|8-11||4’5’’ – 4’9’’||24 – 28’’||24’’|
|11+||> 4’9’’||> 28’’||26’’|
How To Size A Road Bike? (Apart From Height)
The picture below shows you a detailed anatomy of a bicycle. Bike manufacturers often use several of these terms to explain their size selection. Therefore, the first step is to understand the meanings behind them.
Do not let the abundance of information fool you because we don’t need to cover all the concepts in the picture. Pay your close attention to the important ones as follows.
Seat Tube Length
This term refers to the distance from the center of the bottom bracket to the top of the seat tube. In the past, manufacturers used it to measure road bikes, but this method has become outdated in modern models.
The root comes from the difference in the seatmast, causing the parameter to lose its optimal accuracy. For example, some latest bike models serve an expansion above the junction with the top tube.
Instead, brands apply an approximation to maintain compatibility with the well-known centimeter frame (like 54, 56, or 58cm bike size).
Top Tube Length
It is not easy to measure with top tube length as modern bikes are often equipped with sloping ones. The actual size may vary due to this angle, so the bike geometry has defined a consistent measurement known as the effective top tube length.
In detail, you complete your work with a top horizontal length parallel to the ground, no matter what angle the top tube creates. The distance is calculated from the center of the seatpost to the center of the head tube.
Reach & Stack
Manufacturers now add reach and stacking to reinforce the two terms above and size comparison between brands. A plus of these two new concepts is the independence of the frame design thanks to the right angle – the intersection of the top tube and the bottom bracket.
Specifically, reach is the horizontal distance while the stack starts vertically. A plumb line is handy for your measuring task, but it isn’t easy to get accurate readings. You should ask for an assistant and repeat the process several times to get consistent results.
Or else, you can apply this method:
- Measure the length of your torso, from your shoulder to your hip
- Measure a span of your arm (keep one arm parallel with the ground and record the distance from your shoulder and your fingertips)
Your reach = [(the torso length + one arm span)/2] + 10 cm (or 4 inches)
The wheelbase that lies between the front and rear axles has a strong influence on the size and quality of the frame. It would be best to consider corresponding to the actual body length to assess ruggedness. For example, the long handlebar leaves a wide ground clearance and adds stability.
Measurements are fairly easy, but we recommend repeating them a few times for the best accuracy. You’d better push the fork forward to eliminate misalignment. The best final step should cover the average value of the wheelbase length on both sides to compensate for the deviation caused by the fork.
Like the terminology above, chainstay length contributes to the wheelbase and handling capacity of the frame. It comes from the center of the bottom bracket and extends in line to the center of the rear dropout. A short distance offers agility, while a long one enhances stability.
Frame Geometries Is The Game-Changer
The sad news is that three sizing charts are for references only as each manufacturer provides distinctive designs and bike sizing guides. Even if the sizes appear the same, some brands determine their products by different factors such as seat tube length or stack & reach.
The advantage of this approach is that it eliminates the dependency on the frame angle that may seem ambiguous to show off the experience and cycling posture.
We are motivated to offer in-depth research to ensure you purchase the perfect bike. After getting insights into the bike anatomy discussed in the previous section, now let’s distinguish between the three main types of frames recently.
Basic models have an upper tube level with the ground that reduces the space of the cockpit. This minus affects the stand-over height and leads to a retracement of this frame in the current market.
The slanted top tube characterizes a compact frame. Some models thus own a seatpost 2-3 inches longer than traditional ones.
You can also recognize compact road bikes by the short wheelbase and the small triangle in the back with a seat tube on one side. This innovative design offers a larger ground clearance than its predecessor, resulting in many times as responsive as before.
Thanks to these great pluses, this type of frame is a favorite among buyers when they consider an efficient road bike.
It is a daunting task to draw a faint line between compact and semi-compact frames. The latter inherits almost every feature of its cousin except for the slightly smaller top tube angle.
As a result, the effective top tube length lengthens while the base clearance decreases. Of course, your riding experience changes lightly, but only the trained eye will be able to notice.
Tips To Get The Bike Fit
Getting Your Saddle In The Right Position
Your saddle might be too high when you sit on the pedal, and your toes cannot touch the floor. Or else, it is so low that you have to bend your knee when putting your feet on the ground. There is no good in either case.
So, what is the exact height? Follow our guide to install the proper saddle position.
- Stand over the bicycle and place your dominant foot on the pedal for a slight bend in the knee. Put the other foot on the floor.
- In that posture, there should be some inches of the seatpin (or seatpost) visible to your eyes, meaning it isn’t hidden behind your thigh. Note that compact bikes come with smaller frames, so more seatpin will show.
- Keep the saddle flat or at a small angle, depending on your riding style.
- If you suffer from an inconvenience, especially in reach, change the position in the rails little by little. We recommend altering until you notice the center of the kneecap is in a straight line with the ball of the foot.
Install The Correct Tire Sizes
Do not forget that bicycles require parts, including tires, to work as a whole to produce the best performance. The right tire makes your ride easier. Here is a quick rundown of road bike tire basics:
- Tire manufacturers approach sizing by dimension. However, many different measurement systems exist, such as ISO, French size, ETRTO, etc.
- Wide tires make smooth riding feel like gliding on roads; conversely, small ones roll faster because of less air inside.
- Most road bikes are compatible with tires between 23 – 28 mm.
See more: Bike Wheel Size Chart
Setting The Stem Length Or Saddle Height
Either of these changes (or both) affect your reach or, in other words, performance and processing power. To check if you need to make adjustments, try these steps:
- Sit on the bike with a ready-to-ride posture. Your hands are at the top of the handlebars.
- Check the bars and ensure your view is not obstructed by the front axle. If the bar stays behind the axle, this implies a short reach and vice versa.
What To Do If You Are In Between Size?
Sizing up or down? – It can be your concern in some odd cases. Here are some of our practical tips when we are in a similar situation:
- Stretch and touch your toes: When you succeed in this pose, your body is flexible and ready for a smaller frame and vice versa.
- Compare arm span with height: Take a bigger size if you have long arms.
- Test ride: Nothing is more accurate than how you feel on both pedals.
- Just go with the smaller one since there is much room for adjustments later.
How Do You Know If A Road Bike Is Too Big?
Sometimes your choices can go wrong, and you end up with too huge frames. It is sad news if you notice the following signs:
- It is impossible to stand over the bicycle without touching the top tube.
- The front wheel often lifts off the ground
- You struggle to steer and turn your way
- Discomfort and pain disturb your cycling
- You fail to implement technical actions
What Happens If Your Bike Is Too Big?
Based on our experiences, a large frame puts pressure on your posture. It requires an overwhelming stretch, thus causing pain in the back, knees, neck, and shoulders. Another obvious problem is over-handling at turns or overtaking obstacles.
One thing is for sure: The shape of the bike speaks volume for the riding experience, as are aerodynamics, reach, comfort, and efficiency. Hence, you must know the bike frame size road and pick a horse that works well with your height and leg inseam.
Of course, there is nothing better than going straight to the bike shop and testing them out one by one. Do not worry if you are in the middle or on the edge of your size; our tips on size adjustments will point you to the perfect bike.