A wrong size bike is not only inefficient and slow, it can also cause repetitive motion injuries and prevent you from optimal control. Luckily, finding the right fit medium for you isn't all that difficult. Arm yourself with patience to take all the measurements and to try some models: in the end you will find the one that will allow you to pedal comfortably and in style.
Steps
Method 1 of 2: Measure the Frame
Step 1. Remember that you need to buy the right frame based on how you want to use the bike
The frame is the metal structure of the bicycle and, unlike the handlebar, seat and pedals, it is not adjustable. For this reason, it is the most important element to consider when buying a bicycle. There are many models on the market, and their shape changes according to the type of use. Know, however, that there are as many frame configurations, as many as there are bicycle manufacturers, each with "specialist" functions. In any case, most of the time the shape of the frame makes you understand the intended use:
- Road bikes they are the most used for city travel, fitness and competitive races. The frame generally has the shape of a large inverted isosceles triangle whose base (the horizontal tube) is parallel to the ground. Racing bicycles almost always have smaller frames, while touring or city travel bicycles have larger structures. Road bike frames are measured in centimeters.
- Mountain bikes they have a lower center of gravity to ensure the cyclist's balance as he travels rough paths with roots, stones and mud. The central triangle of the frame has a more complex shape, with the top tube inclined towards the seat. Mountain bike frames are measured in inches.
- Cruiser bikes they are clearly American and retro inspired models, with "S" shaped frames that allow for an upright posture. The handlebar is higher than the seat and the pedals are slightly forward, so as to allow maximum comfort while moving around the city. Some call them "city bikes" or "beach bikes" - although in Italy the term city bike means a model more similar to mountain bikes (but less extreme). Cruisers are not suitable for long distances. Finding the right fit means, in this case, is more a matter of individual comfort and taste than precise measurements.
- Children's bikes they have small frames, similar to those of mountain bikes, which allow "baby cyclists" to maintain balance thanks to a low center of gravity. They lend themselves to multiple modifications to adapt to the growth of children. They are classified according to the size of the wheel.
Step 2. Measure your horse, as this is the most important value when buying a bike.
Get upright with your feet 6 inches apart. At this point you can measure the distance that separates the inside of your foot from the groin, where the leg meets the pelvis. Think of this measurement as the inside seam of your jeans. It is important to know the distance between the sole of the foot and the seat. If you are choosing a mountain bike, turn the value into inches (1 inch = 2.54 cm), while you can leave it in centimeters if you want to buy a road bike. To be precise, proceed as follows:
- Get a thick book with a hard cover and "ride" its back, as if it were the saddle of the bike.
- Stand upright and measure the distance between the top of the book and the floor.
Step 3. Use the horse value to calculate the stem length of the racing bike
Multiply the distance of the horse you measured in centimeters by 0.67; the product is the length of the column that is theoretically most suitable for you (the column is the tube that connects the pedals to the saddle).
- The length of the stem is calculated, although not always, from the center of the crank to the upper edge of the tube.
- Please note that this reading is only a reference value, as you will need to make changes later.
Step 4. Calculate the length of the top tube of a mountain bike from the horse value
Multiply the length of the inside seam of the pants (in inches) by 0.67, then subtract 4 or 5 inches to find the theoretically correct value for the length of the top tube. In mountain bikes it is preferable to use the top tube as a reference and not the column, because the latter changes a lot according to the manufacturer of the vehicle.
-
For example, if your horse is 33 inches, then you will need a bike with a 17.5-inch top tube (17.75-inch ones aren't easy to find) because:
33 "x 0.67 = 21.75"
21, 75" - 4" = 17, 75
- Special bicycle manufacturers such as Lapierre & NeilPryde produce frames with very particular geometries that require different calculations. In this case, multiply the horse's value by 0, 62 (and not by 0, 67).
- Some mountain bike riders still prefer to rely on the value of the stem, just like road models. If the dealer you contact classifies his vehicles according to the size of the seat tube, then multiply the horse value by 0, 185. The product obtained represents the recommended distance between the seat and the center of the crankset (the element to which the pedals are attached).
Step 5. When taking a children's bike, take the wheel size as a reference
Most kids' models are adjustable to suit their growing stages and save you the burden of buying a new vehicle every year. That said, the bike should fit your child's measurements to ensure easy and safe pedaling.
- Children 71-96cm tall: 12 inch wheel.
- Children 96-122cm tall: 16-inch wheel.
- Children 122-152cm tall: 20 inch wheel.
Step 6. Adjust the seat height to match your leg length before trying the frame
It is not difficult to change the height of the saddle, so that it is right for you, and even the perfect frame may seem unsuitable if this element is not adjusted. Raise the seat so that when the pedal is at the lowest point of rotation your knee is slightly bent and not stretched. Ask a friend or shop assistant to hold the bike steady while you mount. Pedal backwards stopping your foot at 6 o'clock of the pedal rotation, and change the seat height until your knee is just a little bent.
- It is very rare that the last person who tried the bike placed the saddle at the right height for you, so you will have to change it before you are convinced that the frame is wrong.
- Be sure not to sway or shift your hips down with each pedal stroke, otherwise your foot will drop too low and your bike setup will not be correct.
Step 7. Find the "reach" that's right for you
There are many measures to take into consideration to find the correct distance between the pedals (or rather their horizontal projection) and the handlebars, but in the end it all comes down to one piece of advice: choose the bike that is most comfortable for you. You can say that the reach is correct for your build if:
- You can use each lever (gear and brakes) comfortably.
- The elbows are slightly bent.
- You can reach the dumbbell by bending at waist level without hunching your back.
- As a general rule, those who use the bicycle to move around the city and for a few walks prefer a handlebar high and close to the seat, while competitive cyclists prefer to "stretch" towards the handlebar.
Step 8. Before purchasing, take a test drive with the suggested frame
Each person has a different body, and the proportions between legs, arms and torso require different frames to ensure good comfort. The horse value is just a reference that you must use to identify a starting frame and then proceed with trials and tests. Try a larger frame and a smaller one than the right theoretical size. If you are undecided between two sizes and both of them seem valid, then evaluate your pedaling style:
- Smaller models are usually lighter and more manoeuvrable. However, the difference is really minimal, and if you find the bike a little uncomfortable in the future, you won't be able to make any major changes. Competitive cyclists and off-road cyclists prefer smaller frames.
- Larger models may have greater reach which forces you to stretch too much. However, you can extensively raise and lower the handlebar angle to customize it to your needs if, during use, you find that this is necessary. People who use bicycles for commuting around the city prefer large and comfortable models.
Step 9. If you can't try the bikes yourself, use an online sizing guide
Although they are tools far from perfect, since they do not take into account the uniqueness of your body, these guides prove to be quite useful in choosing the size of the frame. You can find them online by entering the words "mountain bike / racing / BMX / child frame calculator" in your search engine bar. In most cases you will have to enter your height, horse size and even the intended use of the bike, but in the end the calculator will propose a series of frames that you should try.
Step 10. Remember that comfort is the most important thing
Every individual is different so if you don't feel comfortable on a bike that - in theory - "should" fit, then you need to reevaluate the frame size. Try models of different sizes and feel free to change the position of the handlebars and seat until you find the ideal configuration.
- Rent several bikes for a couple of days each for more accurate assessments.
- Talk to the shop assistants, even if they are an online retailer (look for the customer service number). Tell them about any problems you are having and discuss possible causes with them.
Method 2 of 2: Make Changes
Step 1. Remember that you need to change the seat and handlebar height to really fit the bike to your needs
Buying the right frame is only the first part of the job. Think of the measures as a draft, a guideline you must follow for all subsequent changes. Of course, you will have to take care of a lot of details before you are sure that everything is perfect.
Step 2. If you experience knee pain, change the seat height slightly
Although you should adjust this parameter before buying the bike, small changes may be required to make the bike really comfortable. Remember to rest only the forefoot on the pedal and not to sway with your hips with each pedal stroke.
- If the back of your knee hurts while pedaling, then the seat is too high. Lower it 1-2 cm.
- If you experience pain in the front of the knee, then the seat is too low and you need to raise it 1-2 cm.
Step 3. Adjust the seat advance to change the distance between the seat and the handlebars
Loosen the bolt under the seat and move it forwards or backwards several centimeters. Make sure you position it correctly, so you can reach the handlebars effortlessly.
- If the seat is in the right position, then you can stand up on the pedals without pulling the handlebars.
- If you have difficulty getting up, reaching for the handlebars or feeling numb in your fingers, the seat is too far back.
- If you have trouble going downhill and / or experience shoulder pain, then the seat is too far forward.
Step 4. Start riding the bike with the seat parallel to the ground
Use a carpenter's level to make sure it is perfectly level so that your weight is evenly distributed. Some people prefer a slightly sloped seat, but it is always best to start with one on level ground. However, if you feel discomfort you can follow these tips:
- Women usually prefer to tilt the seat tip slightly downwards.
- Men prefer a seat that is slightly tilted back.
- Loosen the bolt on the side of the seat to change the angle. This is a very simple trick and, after changing the angle, remember to lock it again. Some older models have two adjustment nuts and you will need to tighten one and loosen the other at the same time to change the angle of the saddle, just like a swing.
Step 5. Adjust the handlebar position to ride the bike comfortably
You should pedal as comfortably as possible, so the changes vary from person to person. You must be able to control the medium without experiencing pain in the lower back. Most beginners prefer the handlebars to be at the same height as the saddle, while road racers or mountain bikers prefer the handlebar to be 3-5cm lower than the saddle. The elbows should be slightly bent and the fingers resting lightly on the handlebars, as if they could play a piano freely. The position of the handlebar is determined by four elements:
- Length of the horizontal tube: this is the distance between the seat and the handlebar. This value is related to the type of frame you have chosen and, unless you have a very disproportionate body (bust too long or short in relation to the legs), it should be correct if you buy the right size frame for you.
- Head tube length: is the distance that separates the top tube from the handlebar. The higher the steering, the further away the handlebar is from the seat. A head tube costs between 20 and 150 euros and is one of the first changes that are made to adapt the frame to your torso. When the steering is long, you are forced to lie forward in a more aerodynamic position, while when it is short you can stay with the back raised and with a more relaxed posture.
- Handlebar angle: this parameter can be changed regardless of the length of the head tube. To do this you have to loosen the four bolts that are located where the steering is fixed to the handlebar, and tilt the latter according to your preferences. This is a perfect way to change the handlebar position by 3-7cm - with a big impact on ride comfort.
- Handlebar height: can only be modified by adding or removing metal spacers at the point where the steering is fixed to the frame. To proceed, loosen the nut that sits above the steering and then the two bolts that secure the steering to the frame. At this point you can remove the handlebar and insert or remove the spacers according to your needs. These are minimal changes, however, as there is never much room to put several spacer washers.
Advice
- It is easier to use a bike that is too large than one that is too small, so if you are undecided between two sizes, consider buying the larger one. Small bikes are more strenuous and can cause joint injuries.
- The measurements of mountain bikes are often expressed in inches, while those of racing bikes are in centimeters.
