Frame Size Chart
Easily the most important aspect of selecting a new bike is achieving the right fit. Forget the in’s and out’s of titanium vs. steel vs. aluminum, ignore the road tests and race wins. One thing matters more than anything else when you select your new bike—that it fits you!
When a cyclist fits her bike well, she rides more comfortably and efficiently. She rides with more power, and yet the effort comes easier to her. Her body is relaxed, her bike handling skills almost second nature.
True, setting up your ideal position on a bike takes some time, and can be difficult. Why? We cyclists hear conflicting advice, and conflicting formulas, on sizing and positioning.
Pls take time to read the following which tells you what should be done exactly when u getting a bike. You are investing a lot of money on a bike and we should make sure that we get our right bike.
To measure your inseam, get a pencil and a book that has a binding about 2 inches thick.
Take your shoes off and stand facing a wall. Put the book between your legs, with the binding facing up and your feet about 6 inches apart. Hold the book firmly under your crotch - you should feel the same amount of pressure as sitting on your bike saddle. Make sure your legs are straight, and hold the book square against the wall. Mark the spot on the wall at the top of the book. Measure the distance from the floor to the mark - this is your inseam.
For accuracy, repeat the measurement several times and calculate the average. You may need to interpolate for height and shoe size. Shoe size is used to help calculate appropriate top tube.
EXAMPLE: Your measurements are inseam of 32 inches, height 5'9" and shoe size 9.5. Your inseam indicates that you need a seat post of 55 cm center to top. Subtract 1.5cm to get center to center of 53.5. Your height and shoe size indicate that your body is proportioned more in the torso than legs, so you will need a longer stem or top tube of about 56. If the frame you want is 55c/t, but has a top tube of 55 - just add 1 cm to your stem size.
Frame Size
Frame size refers to the length of the frame’s seat tube. Pro frames are measured along the seat tube in one of two ways, center-to-top (C-T) or center-to-center (C-C). C-T measures the distance from the center of the bottom bracket to the top of the top tube or seat lug (See image bellow). C-C measures from the center of the bottom bracket to the center of the top tube. Since C-T measures to a point higher on the frame, a frame measuring 55cm C-T would also measure roughly 53.5–54cm C-C, a difference of 1–1.5cm.
To size your C-T road frame, we use a guideline of .67 x inseam length. For example, if you have an 85cm inseam, your C-T frame size would be .67 x 85cm, or 57cm.
LeMond’s formula, from his former coach, Cyrille Guimard, establishes C-C size by the formula .65 x inseam length, which yields virtually the same frame size when you add the 1–1.5cm difference between C-C and C-T.
Larger riders (6'0" and up) may find that this formula puts them on a too small, and uncomfortable, road frame. A taller cyclist who wants a more comfortable frame may be better off selecting a frame 27–28cm less than inseam length, C-T.
For a mountain bike, we start by recommending a frame in the range of 10–12cm smaller than you take in a road frame. For example, if you ride a 55cm C-T road frame, look for a 43–45cm (17–18") C-T mountain frame.
In many ways, though, it is more important to fit a mountain frame by the top tube length needed, rather than by the seat tube length. For instance, you might be able to get to the proper frame clearance, saddle height and neutral knee position (see below) on either a 17" frame or a 19" frame. Yet the 19" frame will likely have a top tube 1" longer than the 17" frame, which changes your stem length accordingly. Or, one manufacturer’s 17" frame may give you a 22" top tube, while the next one’s 17" gives you a 22.8". More on this below… just make sure that you’ll be able to work out your top tube and stem length for a given frame.
With the right frame size, you’ll be able to set your correct saddle height, which will be within a centimeter of .883 x inseam length, measured from the center of the bottom bracket to the low point of the top of your saddle. This allows full leg extension, with a slight bend in the leg at the bottom of the pedal stroke.
LeMond recommends that you then shorten this length by 3mm when using clipless pedals. Also, you might consider a slightly taller saddle height if you ride with your toes down and your heel raised. Most importantly, make any changes in saddle height gradually, and give your body time to adapt to the new position
Neutral Knee Position
Next, put your bike in a stationary trainer, raising the front wheel to level the bike. Check your position with a video camera or mirrors in front and to the side, or with the help of a friend. Position your cleats with the ball of your foot directly over the pedal axle, and in line with any natural "toe-in" or "toe-out" foot position. Warm up by riding easily for 8–10 minutes.
Then, as you continue to look ahead, slowly stop pedaling, and bring the cranks to rest at horizontal, parallel to the ground. Check the position of your forward knee relative to the pedal spindle —for a "neutral knee position," you’ll be able to drop a plumb line from just below the front of the forward kneecap, and have it bisect the pedal spindle and ball of your foot below. Remember to not raise or drop your heel or hip as you check this. Then, move the saddle fore or aft, as needed, to achieve this neutral position.
The neutral knee position serves as a good starting point for most cyclists, though many adjust it from here: long distance (stage) racers and mountain bikers often move the saddle back by 1cm or more, for power, and sprinters may move it forward, “getting on top of the gear” for quick acceleration.
One more note on frame size and geometry: if you cannot move the saddle back far enough to get your knee to the neutral position, you should look for a frame with a more relaxed seat tube angle, or consider a slightly larger frame; if you have trouble moving the saddle forward enough, look for a steeper seat tube angle on your next frame, or consider a smaller frame. For most frames, a seat tube angle shallower by 1° moves the seat lug 1cm back, relative to the bottom bracket.
Top Tube and Stem Length
Next, dial in the correct "reach" to the bar, or horizontal fit. Proper reach gives you easier breathing, better neck and lower back comfort, and better weight distribution and bike handling.
That "ideal position" varies here more than anywhere else for cyclists, depending on riding style, flexibility, body proportions, and frame geometry, among others. And, your upper body position will evolve with more hours in the saddle. That is, you may find that you develop a lower, longer position as your fitness and flexibility improve. As Phinney notes, though it may be difficult to achieve a truly flat back, we cyclists should all strive to be “longer” across the top of the bike.
Unfortunately, there is no formula for sizing the top tube and stem that works as well as the inseam method. One indicator comes from glancing down at the front hub while riding in the drops; your view of the the front hub should be obstructed by the handlebar. I Recommend that your elbows, bent at 65–70° with your hands in the drops, should be within an inch or two of your knees at the top of your stroke.
Measure your current bike’s top tube and stem. Then, decide how you’d like to alter that fit; add the top tube length to the stem length to get your overall top dimension. The very reason we stock stems in 1cm increments, from 7cm to 14cm, is just to let you dial in your best top tube and stem length.
Choosing the right crank arm length, like the rest of this, comes down to your size and riding style. Longer cranks give you more leverage, helpful if you like to push big gears at a low cadence (climbing, time trialing, etc.). On the other hand, if you like to spin at a high cadence, you’ll do better with standard cranks. As a starting point, we often recommend 170mm cranks on 54cm C-T road frames and smaller, 170–172.5mm cranks on 55–61cm frames, and 172.5–175mm cranks on 62cm frames and larger. Mountain bikes generally get cranks 2.5–5mm longer than road bikes; that is, you might want a 175mm crank on your mountain bike if you’re set up with a 172.5 on your road bike.
Bike Sizing Worksheet
| Inseam
| Height | Shoe size | Frame size
| Top tube
|
| 36 | 6'4" | 11.5 | 62 | 59 |
| 35.5 | 6'2.5" | 11 | 61 | 58 |
| 34.75 | 6'1" | 10.5 | 60 | 57.5 |
| 34.25 | 6'0" | 10.5 | 59 | 57 |
| 33.75 | 5'10.75" | 10 | 58 | 56.5 |
| 33 | 5'9.5" | 9.5 | 57 | 56 |
| 32.5 | 5'8.75" | 9 | 56 | 55.5 |
| 32 | 5'8" | 9 | 55 | 55 |
| 31.25 | 5'7" | 8.5 | 54 | 54.5 |
| 30.75 | 5'6" | 8 | 53 | 54 |
| 30 | 5'5" | 7.5 | 52 | 53 |
| 29.5 | 5'4.5" | 7 | 51 | 52 |
| 29 | 5'4" | 7 | 50 | 51 |
| 28.5 | 5'3" | 6 | 49 | 51 |
Adults bikes are generally measured by frame size (the measurement between the centre of the bottom bracket to the top of the seat tube).
| Riders Height | Mainly Off Road Use | Mainly On Road Use | Road Racing Bikes |
| In Feet & Inches | Frame Size Required | Frame Size Required | Frame Size Required |
| 4 feet 8 to 5 feet 0 | 12 to 14 inches | 13 to 15 inches | 46 to 48cm |
| 5 feet 0 to 5 feet 4 | 14 to 16 inches | 15 to 17 inches | 48 to 50cm |
| 5 feet 4 to 5 feet 8 | 16 to 18 inches | 17 to 19 inches | 50 to 52cm |
| 5 feet 8 to 6 feet 0 | 18 to 20 inches | 19 to 21 inches | 52 to 56cm |
| 6 feet 0 to 6 feet 2 | 20 to 22 inches | 21 to 23 inches | 56 to 60cm + |
Child needs a bike - What size do they need?
Children's bikes are generally measured by wheel size, rather than by frame size.
| Age of Child | Wheel Size |
| 2 to 3 Years | 12 |
| 3 to 4 Years | 14 |
| 4 to 5 Years | 16 |
| 5 to 6 Years | 18 |
| 6 to 9 Years | 20 |
| 10 to 13 Years | 24 |
Bike fit wins hands-down as the most important consideration when buying a bicycle, weighing in above such considerations as materials used, overall weight and brand. That's because a poor fit means discomfort, inefficient energy transfer and slower riding times – not to mention poor handling. Should you sacrifice a good fit for a good deal? Certainly not.
The most important measurement when sizing a bicycle is your inseam length – essentially the inside length of your pant leg from crotch to floor. Since this is the primary measure used to calculate your best bike size, don't base your inseam simply on your jeans size. You need to be more precise. Here's how to do it:
Inseam
- Stand with your back against a wall.
- Spread your feet 6-8” apart on a hard, smooth surface.
- Place a book between your legs and up against the wall, spine up; raise it until snug against your crotch (this mimics your bike seat).
- Have another person measure from the top of the book (spine) down to the floor.
Measuring Your Torso and Arms
You need your torso and arm lengths to help determine your ideal top-tube length. Here are a few steps to determine each measure.
Torso Length
- Repeat the first three steps for measuring your inseam.
- Measure from the spine of the book (the top) to the small “V” in your throat just above your sternum, in inches.
Arm Length
- Find the end of your collarbone, on the tip nearest your shoulder.
- Hold a pen or pencil in your fist (on the same side as the collarbone you've chosen).
- Have your helper measure from the end of your collarbone to the object in your fist, with your arm outstretched.
Defining a Bike's “Size”
While many bikes offer a size you're familiar with, such as S, M, L or XL, others don't. Many bikes instead provide a “size” listed in inches or centimeters as one number (i.e., 18”). This size or “frame size” of a bike refers to the length of its seat tube. This measure is given in one of two ways: from the center of the bottom bracket to the top of the top tube (C-T) or from the center of the bottom bracket to the center of the top tube (C-C). Sometimes the specific size measure will actually be listed (“bottom bracket to top of top tube”) instead of simply calling a measure the bike's “size.”
Road Bike Fit
To obtain your ideal seat tube height (or “size”) for a road bike, multiply your inseam (in cm) by .67 to get C-T length (or by .65 to get the C-C size for your seat tube). If you measured your height and inseam in inches, convert inches to centimeters by multiplying inches by 2.54 (Example: 30 inches x 2.54 = 76 cm).
For the best fit on a road bike, you also need to know your ideal “total reach'” which is the combined length of the top tube and stem. Unfortunately, there are many different ways to convert upper-body measures into the total reach for a road bike.
Total Reach = [(Torso Length + Arm Length) / 2] + 4 inches = (Top Tube + Stem)
Saddle height, which is measured from the center of the bottom bracket to the top of the bike seat, is another measure that helps you custom fit your bike.Since saddle height is adjustable on road bikes, this measure is not as important at the time of purchase as seat tube length and is not included with bike specifications. However, we have included an approximate saddle height in the table below (based on inseam) so you can use it as a starting point with your new bike.
Road Bike Sizing TableIdeal Frame Size (C-T Measure) | |||||
| Inseam (in.) | Inseam (cm) | Seat Tube (cm) | Seat Tube (in.) | Saddle Height (cm) | |
| 27 | 69 | 46 | 18 | 61 | |
| 28 | 71 | 48 | 19 | 63 | |
| 29 | 74 | 49 | 19 | 65 | |
| 30 | 76 | 51 | 20 | 67 | |
| 31 | 79 | 53 | 21 | 70 | |
| 32 | 81 | 54 | 21 | 72 | |
| 33 | 84 | 56 | 22 | 74 | |
| 34 | 86 | 58 | 23 | 76 | |
| 34 | 89 | 60 | 23 | 78 | |
| 36 | 91 | 61 | 24 | 81 | |
| 37 | 94 | 63 | 25 | 83 | |
Note: Taller riders (over 6'1”) may want to lean toward a slightly larger frame size (approx. 1-4 cm extra seat tube length) when selecting a size based on this table. For example, a tall person with a 36-inch inseam would require a 61 cm seat tube (size 61) based on the table, but might actually prefer a 63 cm seat tube.
Mountain Bike/ Hybrid Bike Fit
When sizing a mountain bike (MTB) or commuter bike, the most important thing to look at is the “stand-over height.” The stand-over height of a bike frame, or the distance from the center of the top tube to the ground, should be 2-5 inches less than your inseam. Aggressive mountain bikers will need 4-5 inches difference between stand-over height and inseam length, while commuters only need about 2 inches of clearance.
Another way to find your MTB size is to simply subtract about 10 cm (4 inches) from your ideal road bike frame size to find your MTB frame size. Thus a rider with a 33-inch inseam would need a 22-inch road frame and an MTB/ commuter frame around 18 inches.
Note: Most mountain bike measures are given in inches, while the majority of road bike specifications are only offered in metric units.
Since MTB seats are easily raised and lowered and the rider almost always stays in an upright position, the length of an MTB's top tube is as important as the frame size. This is important because if the top tube is too long, it will be difficult to keep your weight over the front wheel when riding uphill. You'll want to calculate your best top-tube length (measure in inches) and be sure the bike you're interested in offers a similar length. If you're looking at a bike's specifications on this website or any individual brand's website, this specification may be listed as the “effective top tube.” This term describes the imaginary horizontal top tube length for any bike with a top tube that is not perfectly horizontal.
Approximate top-tube length = [(Torso Length + Arm Length) / 2] – 6 inches
MTB/ Commuter Bike Sizing Table | |||||
| Inseam (in.) | Stand-over Height (in.) | Seat Tube (in.) | | | |
| 27 | 22-25 | 14 | | | |
| 28 | 23-26 | 14 | | | |
| 29 | 24-27 | 15 | | | |
| 30 | 25-28 | 16 | | | |
| 31 | 26-29 | 17 | | | |
| 32 | 27-30 | 17 | | | |
| 33 | 28-31 | 18 | | | |
| 34 | 29-32 | 19 | | | |
| 35 | 30-33 | 19 | | | |
| 36 | 31-34 | 20 | | | |
| 37 | 32-35 | 21+ | | | |
Fitting a Comfort/ Cruiser Bike
Comfort bikes don't require a custom fit, but the closer the frame is to the perfect size, the more you'll enjoy your rides. Sizes are general, usually listed simply as S, M, L or XL. Base the size on your approximate height and inseam measures.
Compared to men, women and children (especially young girls) have shorter arms and longer legs. This means that they will have a slightly different fit on a bike, particularly on road bikes.
An easy rule of thumb for women and children is as follows: If you fall somewhere on the border between two bike sizes, go with the smaller size. It’s easier to control a smaller bike, and the saddle height can be increased easily. Also, realize that stand-over height will be more important for female and younger riders than will top-tube length.
If necessary, women and younger riders can change out the stem on their bike to a shorter stem, which will bring the handlebars closer to the rider, and can change out the handlebar for a narrower bar that better matches their shoulder width.
Once the Bike Arrives: Minor Adjustments
Once your new bike arrives, you may need to fine-tune a few dimensions to account for your degree of flexibility and personal riding style. (Of course, we'd like to believe you’ve chosen the right frame after reading this guide!) Here are a few examples of minor alterations you can do at home or have done at a shop.
Note: We recommend that you always have a professional from a bicycle shop make all adjustments to any bicycle.
Adjust saddle height
Adjust your saddle height so you reach a near-full leg extension with every pedal, and experience a slight bend in the knee at the bottom of a pedal stroke. The correct saddle height will keep rides easier on your knees and allow for powerful downstrokes.
Adjust saddle tilt
There is no universally correct saddle tilt angle. This adjustment is simply based on comfort preference. Adjust the saddle tilt so that a.) you are comfortable, and b.) you don’t slide off the front of the saddle. Men tend to prefer the saddle nose tilted slightly up, while women tend to prefer it tilted slightly down.
Adjust stem length for a custom fit
Stems are often sold in 1 cm length increments, so that you can outfit your bike with the perfect stem for comfortable posture. Stem rise can also be increased for a rider with a shorter reach. Most bike shops will carry a variety of stem sizes.
Find your optimal handlebar size
Shoulders
The handlebars for road bikes come in multiple widths and configurations. If you want to custoimize your handlebars, select handlebars that are the same width as your shoulder joints. Go narrower for a more aerodynamic ride, or wider to have more room for your chest to experience easier breathing and added leverage.
Adjust handlebar height
If your back is getting sore or cramped after riding, you may need to raise the handlebars an inch or so. Bear in mind, though, that you’ll want the handlebars as low as possible if you’re going for aerodynamics on a road bike.
Other Adjustments
For any custom fits, such as adjusting your seat tube angle or crank length (i.e., bigger cranks for slow pedaling in higher gears), head to a bike shop and get help from a pro.
Hope you guyz choose the right sized bike. Lets make cycling better.
Happy Cycling!!!
Arif
performance_biker@yahoo.com
9894083316
