Which bike size you need
Why Bike Size Matters
- When selecting a bike, the most important aspect is obviously that the seat can be adjusted to your height so you can pedal efficiently, be comfortable and safe. If the frame is too small it's impossible to raise the saddle enough.
- When buying a bike here the first question I ask is 'How tall are you ?' and then I verify the bikes you are interested in to make sure they are a good fit. So you don't have to worry because I won't sell you a bike too small or too tall. You will find in the description a range for example Your height: 5'8" to 5'11" (173 to 180cm) approximately (?). Frame size = 22.75in/57.5cm
- Unfortunately a lot of ill-informed buyers will just purchase any used bike on the internet and are stuck with a bike way too small for them. There are much more teenager's size and small adult bikes available. Most vendors don't know anything about bike size themselves and will simply sell to anyone interested, they don't offer any warranty anyway.
See adjusting the saddle section
- For safety it is also important that there be at least 2cm or 3/4 inch between the frame and your crotch so you won't hit the bar when coming down from the saddle. Raise up your pants to verify.
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There should be at least 2cm or 3/4 inch between the frame and your crotch
- The bike must not be too long and forcing you to lean forward with arms stretched, or too short forcing you in a cramped position with arms too close to your body. So it's not simply a question of installing a longer seat post if the bike is too small, or lowering the seat as low as it can go if too tall.
- The length of the bike or wheelbase is more or less important depending on the type of bike and riding position. On bikes with an upright riding position the length is less critical, you simply sit higher if you're taller and you can use an extra long seat post (more below). This explains why city bikes are manufactured in only 2 or 3 different sizes. Portable folding bikes are made in only one size for all.
There are some quick methods explained below to determine approximately what size of bike you need. Bike sizing charts are also found below so you can determine in advance if a bike is a potential fit depending on your height and bike type. However, people having different leg to body ratio, the only way to know for sure is to try the bike and adjust the seat height.
Important! the information below applies to older bikes only. Newer men's and ladies' bikes have a lower frame with a longer seat post. On older men's bike the top horizontal tube is really horizontal. Newer bikes have different frame geometry, the top tube is not completely horizontal but lower toward the saddle.
On older men's bike the top horizontal tube is really horizontal.
Measuring Bike Frame
- The size of a bike is the length of the tube supporting the saddle, measured from the top of the seat tube (not counting the seat post) to the axis of the bottom bracket (axis of the crank)
- Most older adult bikes have a frame size between 18in and 25in. and the same model of bike was manufactured in different sizes. For example vintage Raleigh Sports city bikes were produced in only 2 sizes: 21" and 23" frame for men, and 19.5" and 21" frame for ladies. Very popular road bikes were produced in more sizes, for example the Velo Sport Appalache available in 47, 54, 57, 60, 63, 66cm.
The bike size you need depends on the type of bike
- Different bike sizing charts exist for mountain bikes, road bikes, BMX's, etc... Different types of bike have different frame geometry, wheel size, riding position and other factors influencing the size you should purchase.
Quick methods without measuring tape and bike sizing charts
- Method #1:
- Divide you height by 3. For example I am 5' 9" = 69" so I need a bike frame of 23" approximately.
- Method #2 if you have a bike in front
of you:
- This method works if you have a bike in front of you and it's a men's road, men's mountain bike or men's city bike, with a horizontal top tube.
- Step over the horizontal bar, don't sit on the bike, put your 2 feet flat on the ground, legs extended.
- There should be at least 2cm or 3/4 inch between the frame and your crotch so you won't hit the bar when coming down from the saddle. Raise up your pants to verify.
- On road bikes there shouldn't be more than 5 cm or 2 inch clearance, otherwise the seat might not come high enough or the bike won't be long enough. So 2 to 5 cm (3/4" to 2") clearance between frame and crotch is what you should look for.
- For mountain bikes it's safer to have more clearance for off-road use. Clearance of 5 to 13 cm (2" to 5") between the bar and your crotch is what you should look for.
- This rule doesn't apply for ladies bikes with a slanted frame and modern mountain bikes with unconventional frame design. See bike sizing charts below instead.
- You shouldn't use a bike if the clearance is less than 2cm (3/4 in) as described above. Kid's riding a bike too tall for them is a major cause of accident.
Short riders under 5ft 2in
- Contrarily to what you might think you can easily find a bike for your height. Petite women represent a good portion of my clientele.
- Almost all ladies' bikes with a slanted ladies frame are built to accommodate riders between 5ft 0in and 5ft 8in. At 5ft 2in or under select a frame size of 18in, 19in or 20in.
- If you are shorter than 5ft you should also look at junior bikes with smaller 24in wheels and you will have an even wider choice (full size adult bikes have 26, 27 or 28 inch wheels). Junior bikes with 24in wheels are listed in the kid's bike section.
- Under 5ft 0in you can try a full size ladies' bike with 18in or 19in frame but you would probably feel and look better on a junior bike with 24in wheels.
Women 5ft 8in and taller
- you need a frame of 22in or taller. Unfortunately ladies' bikes with slanted frame were not produced above 21in. You should be looking at men's bikes instead. You can always try a ladies' bike with 21in frame and a longer seat post, but the bike might be too short, the handlebar won't go high enough, your knees might hit the handlebar.
Tall riders 6 ft and above
- unfortunately tall bikes are much harder to find for reasons I can't fully understand. If you are 5ft 10in or above, you need a frame size of 23" (58cm) or above. See bike sizing charts below.
- Curiously, even if the average male height is 5ft 10in in North America, manufacturers don't produce large numbers of bikes for people above that average. I find few used ones for rebuilt. It's probably because most new bikes are purchased by teenagers, not fully grown adults. So I find large quantities of smaller bikes for people between 5' and 5'6", mostly mountain bikes nowadays, but very few tall bikes.
Bike Sizing Charts
Important! the information below applies to older bikes only. On older men's bike the top horizontal tube is really horizontal. Newer bikes have different frame geometry, the top tube is not completely horizontal but lower toward the saddle. Newer men's and ladies' bikes have a lower frame with a longer seat post.
Road Bike Size
- see Table 1 below
- On road bikes with a leaned forward position, the length of the bike is critical for a comfortable and safe position. Whatever your height you shouldn't compromise on the size and wait until you find one of the correct size. Popular road bikes are manufactured in many different sizes. For example the Velo Sport Appalache from the 80's was produced in 6 different sizes: 47, 54, 57, 60, 63, 66cm to suit everyone.
Hybrid Bike Size
|
Rider's
Height*
|
|
| 18" - 46 cm | 4'
5" to 4' 8" 135 to 143 cm |
| 19" - 48 cm | 4'
8" to 4' 11" 141 to 149 cm |
| 20" - 51 cm | 4'
11" to 5' 2" 150 to 158 cm |
| 21" - 53.5 cm | 5'
2" to 5' 5" 158 to 166 cm |
| 22" - 56 cm | 5'
5" to 5' 8" 165 to 173 cm |
| 23" - 58.5 cm | 5' 8" to 5'
11 " 173 to 181 cm |
| 24" - 61 cm | 5' 11" to
6' 2 " 180 to 188 cm |
| 25" - 63.5 cm | 6'
2" and over 188cm and over |
| *The only way to know for sure is to try the bike and adjust the seat height. | |
Table 1: Bike frame size for older road bikes and hybrid bikes
City Bike Size
- See table 2 below
- With city bikes frame size is not as important as with road bikes, because the riding position is more upright, most of the weight is on the seat. Most vintage city bikes were produced in only 2 sizes, typically 19" and 21" frames for ladies, 21" and 23" frames for men.
- Shorter people will easy find a suitable vintage city bike, but tall ones are harder to find. You won't find a vintage ladies' bike taller than 21in, or a men's taller than 23in. You must be able to adjust the seat high/low enough, and if the bike is too small your knees will hit the handlebar when turning.
- If you are shorter than 5ft you should also look at junior bikes with smaller 24in wheels and you will have an even wider choice (full size adult bikes have 26, 27 or 28 inch wheels). Junior bikes with 24in wheels are listed in the kid's bike section.
- Females above 5'8" should look at men's city bikes instead.
- Males above 5'10" must use a 23" city bike and put a longer seat post if required.
|
Rider's
Height*
|
|
| 18" - 46 cm | 4' 5" to 5' 0" |
| 19" - 48 cm | 4' 8" to 5' 3" |
| 20" - 51 cm | 5' 0 " to 5' 5" |
| 21" - 53.5 cm | 5' 2" to 5' 8" |
| 22" - 56 cm | 5' 5" to 5' 11" |
| 23" - 58.5 cm | 5' 8" to 6' 2" |
| *The only way to know for sure is to try the bike and adjust the seat height. | |
Table 2: Bike frame size for older city bikes
Mountain Bike Size
- See table 3 below or download mountain bike sizing chart from ebicycles.com
- you can also use the frame size calculator from ebicycles.com at http://www.ebicycles.com/article/bicycle-frame-size-charts.html
- With mountain bikes you need a bigger clearance between your crotch and the frame to avoid injuries. On modern mountain bikes the horizontal top tube is not actually horizontal but slanted or U-shaped.
|
Rider's
Height*
|
|
| 14" - 35.5 cm | 4' 8" to
5'1" 142 to 155 cm |
| 15" - 38 cm | 4'9" to 5'
4" 145 to 163 cm |
| 16" - 40.5 cm | 4' 11" to
5' 7" 150 to 170 cm |
| 17" - 43 cm | 5' 2" to 5'
10" 157 to 178 cm |
| 18" - 46cm | 5'
5" to 6' 1" 165 to 185 cm |
| 19" - 48cm | 5'
7" to 6' 4" 170 to 193 cm |
| 20" - 51cm | 5'
10" to 6' 6" 178 to 198 cm |
| 21" - 53cm | 6'
1" to 6'7" 185 to 201 cm |
| 22" - 56cm | 6'
3" to 6' 7" 191 to 201 cm |
| *The only way to know for sure is to try the bike and adjust the seat height. | |
Table 3: Bike frame sizes for mountain
bikes with 26in wheels.
Download mountain bike sizing chart from ebicycles.com for more accurate data.
Download mountain bike sizing chart from ebicycles.com for more accurate data.
BMX's Size
- download BMX bike sizing chart from ebicycles.com
- or use the frame size calculator from ebicycles.com at http://www.ebicycles.com/article/bicycle-frame-size-charts.html
- With a BMX you need a bigger clearance between your crotch and the frame to avoid injuries. BMX riders like to ride with a very low seat. Most of the time you stand up on the pedals to do tricks.
- As you grow and become an adult, you need a longer BMX frame, or you can replace the straight seat post with a slanted backward seat post.
- The only way to know for sure is to try the bike and adjust the seat height.
Folding Bike Size
- folding bikes are manufactured in one size fits all. Most older folding bikes can be ridden by kids and adults up to 5ft 9in. Above that height some folding bikes saddle won't go high enough. Modern folders can accommodate taller cyclists.
- folding bikes are all equipped with extra long seat posts and handlebar stems so the saddle and handlebar can be quickly adjusted with quick release attachments.
- frame size not very important, the riding position is upright, most of the weight is on the seat, and folding bikes are used mainly for low speed city commuting and cruising.
- the wheelbase (distance between the axis of the wheels) of some folding bikes is almost the same as a full size mountain bike or road bike. But the wheels being smaller it's more stable and agile at low speeds.
- The only way to know for sure is to try the bike and adjust the seat height.
Kid's bike and tricycle size
- Measure the inseam and check table 4 below
- you can also use the bike size calculator from ebicycles.com at http://www.ebicycles.com/article/bicycle-frame-size-charts.html
- Kid's bikes are not measured by frame size, but instead by wheel size.
- As soon as a kid is able to walk he can ride a small tricycle.
- From age 2 to 6, depending on height, a bike with 12 in, 14in or 16in wheels with training wheels. Typically that bike will be good for 2 years or less. Once the kid found his balance, the training wheels can be removed.
- From age 5 to 9, or between 4' and 5' tall, a bike with 20in wheels is better. That's the wheel size of BMX's.
- Pre-teens aged 8 to 13 should use a junior bike with 24in wheels.
- Once they have grown to 5 feet or more, they can start looking in the adult bike alley, but it's better to wait until they are 13 years old at least before buying an adult size bike, otherwise it might be too small when they become fully grown adults.
- The only way to know for sure is to try the bike and adjust the seat height
|
Inseam
|
Wheel
Size
|
| less than 16 in (40 cm) | 12 in |
| 16 to 20 in (40-50 cm) | 14 in |
| 20 to 22½ in (50-57 cm) | 16 in |
| 22½ to 26 in (57-66 cm) | 20 in |
| 26 to 28 in (66-71 cm) | 24 in |
Table 4: Kid's Bike Sizes
Exercise Bike Size
- exercise bikes are manufactured in one size fits all.
- they are all equipped with extra long seat posts and handlebar stems so the saddle and handlebar can be quickly adjusted with quick release attachments.
- frame size is not important because the riding position is very upright, all the weight is on the seat, no need to be leaned forward and aerodynamic when exercising inside!
- the only way to know for sure is to try the bike and adjust the seat height.
Adult Tricycle Size
- Manufactured in one size fits all, usually a small frame such that the seat can be set very low.
- For older riders the seat is often adjusted lower than it should be, so it's easier to sit. However because the tricycle is very heavy and requires effort to move, the seat should be adjusted to the correct height as much as possible, because you will need all the power you have to go anywhere.
- Tricycles use the same seat posts as regular bikes so you can put a longer seat post, if required, to pedal efficiently.
- The only way to know for sure is to try the bike and adjust the seat height.
Tandem Bike Size
- I don't know much about tandem bikes, but since most of them are road bikes or city bikes style, I guess you should look at the road bike chart above.
- The front and rear seats are adjustable independently.
- If the 2 riders have very different height it could be impossible to find a suitable tandem for the pair
- The only way to know for sure is to try the bike and adjust the seat height.
Delivery Bike Size
- see adult tricycle above
Recumbent bike and Trike Size
- too many different frame designs to make general rules, you must try it to know if you can ride it comfortably