Welcome to our complete UK bike size guide. Choose a bike that fits properly, so every ride feels comfortable, predictable and enjoyable. However, choose one that is far too large or too small and even a very good bike will feel awkward.
Below, this bike size guide explains how adult bike sizing works and what 700C, 26-inch, 24-inch, 20-inch and 12-inch actually mean. Additionally, it explains how children’s bike sizing differs from adult sizing and which bikes from the current BlackBike range may suit you.
Find Your Bike in Less Than 60 Seconds
Firstly, gather three things:
- Your height
- Your inside-leg measurement
- Where you actually want to ride
Then use the model-specific sizing information further down this guide.
In a hurry? The chart below plots every Black Bike against rider height, so you can spot yours at a glance.
Adult Bikes Kids and Teens Find a BlackBike
What Size Bike Do I Need as an Adult?
When it comes to adults, there is no single wheel size that automatically corresponds to a particular rider height.
That is because wheel size and frame size are different measurements.
Generally, a 26-inch bike means it has 26-inch wheels. Meanwhile, a 700C bike refers to its wheel standard. However, neither measurement tells you, by itself, whether the frame will fit you correctly.
Rather, adult fit depends on:
- your height
- also, your inside-leg measurement
- frame size
- top-tube and reach dimensions
- likewise, handlebar position
- saddle adjustment
- finally, the style of bike.
Important: Never buy an adult bike based only on the words “26-inch” or “700C”. Those usually describe the wheels rather than the complete fit of the bike.
Bike Wheel Size vs Frame Size: What Is the Difference?
In fact, this is one of the most commonly misunderstood parts of bike sizing.
| Measurement | What It Generally Describes | Example |
|---|---|---|
| 12 inch | Wheel diameter | Young child’s balance bike |
| 20 inch | Wheel diameter | Kids bike, BMX or folding bike |
| 24 inch | Wheel diameter | Older child, teenager or smaller rider |
| 26 inch | Wheel diameter | Mountain, hybrid or city bike |
| 700C | Adult wheel standard | Road, hybrid, commuter or city bike |
| 54 cm | Usually frame size | Road-bike sizing |
| 58 cm | Usually frame size | Large road/fixie-style frame |
| 14, 17 or 19 inches | Can describe frame size | Mountain or hybrid bike frame |
How to Measure Yourself for a Bike
You only need a tape measure and a few minutes, so it is worth doing before you order.
Step 1: Measure Your Height
Firstly, stand barefoot with your back against a wall. Then keep your heels flat and measure from the floor to the top of your head.
Afterwards, write the measurement down in centimetres. If you normally use feet and inches, also keep that measurement.
Step 2: Measure Your Inside Leg
Similarly, stand barefoot with your feet around 15–20 cm apart.
Place a hardback book between your legs and raise it gently until it sits where a bike saddle would normally make contact.
Then measure vertically from the floor to the top of the book.
This is your approximate inside-leg or inseam measurement.
Step 3: Decide What Kind of Riding You Will Do
A rider may fit more than one bike, so your intended use matters too.
| Your Main Use | Bike Type to Consider |
|---|---|
| Work and city commuting | Hybrid, commuter, city, fixie or folding bike |
| Fitness and faster paved-road riding | Road bike |
| Roads plus parks and light trails | Hybrid bike |
| Gravel, countryside and rough surfaces | Mountain or fat tyre bike |
| Longer commuting with assistance | Electric hybrid bike |
| Shopping and relaxed urban riding | Step-through city bike |
| Small flat or train travel | Folding bike |
| Tricks and skatepark riding | BMX |
Not Sure Which Bike Fits You?
Then send BlackBike your:
Height + inside-leg measurement + what you want to use the bike for.
We can then help identify the most suitable model from the current range before you order.
Ask BlackBike Which Bike Fits Me
What Does 700C Mean?
Basically, 700C is a wheel-size standard widely used on adult road, commuter, hybrid and city bikes.
However, 700C does not mean one particular frame size. Two bikes can both use 700C wheels while being designed for noticeably different riders.
Consequently, BlackBike stocks several 700C models covering different riding styles and frame configurations.
What Height Is a 700C Bike For?
Even so, there is no universal height range for every 700C bike.
For example, within the current BlackBike range:
- the GUST 700C Road Racing Bike is listed for riders around 170–183 cm (5’7″–6’0″)
- meanwhile, the GUST Urban Commuter covers around 178–195 cm (5’10″–6’4″)
- the JUHI Women’s Metropolitan City Bike suits around 152–175 cm (5’0″–5’9″)
- finally, the GUST Hybrid Electric Bike fits around 168–185 cm (5’6″–6’1″).
All of them can use adult-sized wheels, yet the suitable rider range differs because the frame geometry differs.
What Height Is a 26-Inch Bike For?
Similarly, a 26-inch wheel does not automatically define rider height.
In fact, the current BlackBike range demonstrates this very clearly.
For instance, the JUHI 26-Inch Hybrid Mountain Bike has a smaller 14-inch frame and is listed for riders around 145–165 cm (4’9″–5’5″).
The GUST 26-Inch City Hybrid Bike, however, uses a larger frame and suits riders around 175–188 cm (5’9″–6’2″).
Same general wheel diameter, but very different rider fit.
BlackBike Size Finder: Find the Right Bike From Our Current Range
Accordingly, below is a practical guide to the bikes currently available through BlackBike. Wherever a specific rider-height range is published for the model, we have also included it.
In addition, every bike below now carries a scale drawing beneath its specification. Each one shows riders at both ends of the fit range standing next to the bike, so you can judge the fit at a glance. Where a range is marked ESTIMATE, we have worked it out from the frame size or the published age range instead, so treat it as a starting point and check with us before you order.
Of course, stock, specifications and availability can change. Always check the linked product page before ordering.
Adult Hybrid, Mountain and Adventure Bikes
GUST 26-Inch Fat Tyre Mountain Bike
| Wheels: 26 × 4.0-inch fat tyres |
| Gears: 21-speed |
| Brakes: Mechanical disc brakes |
| Especially good for: Countryside, gravel, woodland routes, loose surfaces and riders who want maximum stability. |
| Estimated rider height: 172–188 cm / 5’8″–6’2″ (our guide, not a published figure) |
Undoubtedly, this is one of the most distinctive bikes in the BlackBike range. The oversized tyres create a planted riding feel. Consequently, it is a strong choice for riders who value grip and confidence over pure road speed.
Because wheel diameter alone cannot determine fit, contact us with your height and inside-leg measurement if you are unsure.View GUST 26″ Fat Bike
GUST 26-Inch City Hybrid Bike
| Wheels: 26 inch |
| Gears: 21-speed |
| Suspension: Front suspension |
| Brakes: Mechanical disc |
| Published rider height: 175–188 cm / 5’9″–6’2″ |
| Especially good for: Commuting, parks, mixed roads and light trails. |
As a result, it suits taller riders who want one bike for both urban use and weekend rides.View GUST 26″ City Hybrid
JUHI 26-Inch Hybrid Mountain Bike
| Frame: 14-inch small/junior alloy frame |
| Wheels: 26 inch |
| Gears: 21-speed |
| Brakes: Mechanical disc |
| Published rider height: 145–165 cm / 4’9″–5’5″ |
| Especially good for: Smaller adults, older children and riders who want an easy-to-control hybrid. |
Indeed, this is an excellent example of why the phrase “26-inch bike” does not automatically mean a large adult bike.View JUHI 26″ Hybrid
BlackBike Large 700C Hybrid
| Wheels: 700C |
| Frame: Large aluminium alloy |
| Gears: 21-speed |
| Suspension: Front suspension |
| Brakes: Mechanical disc |
| Especially good for: Everyday riding, commuting, park routes and mixed urban use. |
| Estimated rider height: 175–190 cm / 5’9″–6’3″ (our guide, not a published figure) |
Not everyone needs a highly specialised road or mountain bike. If you want one practical bike instead, a 700C hybrid is an excellent place to start.View Large 700C Hybrid
Commuter and City Bikes
GUST Urban Commuter Bike – 700C
| Wheels: 700C |
| Frame: Large aluminium alloy |
| Gears: 7-speed |
| Published rider height: 178–195 cm / 5’10″–6’4″ |
| Especially good for: Taller commuters, students and city riders. |
Is your riding primarily on roads, cycle paths and city streets? Then this lighter urban setup makes more sense than carrying the weight and complexity of a mountain bike.View GUST Urban Commuter
GUST 700C Urban Fixie / Single Speed
| Wheels: 700C |
| Frame: 58 cm large |
| Gears: Single speed |
| Especially good for: Flat city routes, simple maintenance and minimalist urban riding. |
| Estimated rider height: 178–190 cm / 5’10″–6’3″ (our guide, not a published figure) |
In particular, the 58 cm frame makes this one of the larger-frame options in the BlackBike range. So, if you are close to the boundary between sizes, send us your height and inside-leg measurement before ordering.View GUST 700C Fixie
JUHI X5 20-Inch Folding Bike
| Frame: Adjustable folding aluminium frame |
| Wheels: 20 inch |
| Gears: 7-speed |
| Published rider height: 145–185 cm / 4’9″–6’1″ |
| Especially good for: Train commuters, flats, motorhomes, offices and limited storage. |
This is another good example of why wheel size alone can be misleading. A 20-inch folding bike can fit adults comfortably. Meanwhile, 20-inch wheels also appear on children’s bikes and BMX bikes.View JUHI X5 Folding Bike
Road and Fitness Bikes
GUST 700C Road Racing Bike
| Wheels: 700C × 25c |
| Frame: 54 cm |
| Gears: 21-speed |
| Published rider height: 170–183 cm / 5’7″–6’0″ |
| Especially good for: Fitness, faster road cycling, longer paved routes and sporty commuting. |
The slimmer tyres and drop handlebars give this bike a more athletic riding position than a hybrid or city bike.View GUST Road Bike
Electric Bike
GUST Hybrid Electric Bike – 250W Yose Power
| Motor: 250W rear hub |
| Battery: 36V 13Ah removable battery |
| Gears: 21-speed Shimano system |
| Published rider height: 168–185 cm / 5’6″–6’1″ |
| Especially good for: Longer commuting, hills and riders wanting pedal assistance. |
Do you like the versatility of a hybrid but want assistance on longer rides and hills? If so, this is the electric option in the current BlackBike range.View GUST Electric Bike
Women’s and Step-Through City Bikes
A step-through bike can be particularly useful for riders who prefer easy mounting, a relaxed upright position and practical everyday cycling.
JUHI Women’s Metropolitan City Bike
| Wheels: 700C |
| Frame: 41 cm medium step-through |
| Gears: 6-speed |
| Published rider height: 152–175 cm / 5’0″–5’9″ |
| Extras: Rear rack, mudguards and chain guard |
| Especially good for: Town riding, commuting, shopping and leisure cycling. |
JUHI Women’s City Cruiser
| Frame: 41 cm medium step-through |
| Wheels: 700C / 28-inch |
| Gears: 6-speed |
| Published rider height: around 5’4″–5’10” |
| Extras: Front basket, rear rack, mudguards and chain guard |
| Especially good for: Shopping trips, relaxed commuting and everyday city riding. |
View JUHI Women’s City Cruiser
Kids Bike Size Guide UK
In contrast, children’s bike sizing works differently from adult bike sizing.
For children, however, wheel diameter is usually the easiest starting point.
| Wheel Size | Typical Use | BlackBike Options |
|---|---|---|
| 12 inch | Young children learning balance | GUST Balance Bike |
| 20 inch | Older children, BMX and freestyle | Kids BMX / GUST Freestyle BMX |
| 24 inch | Older children and teenagers | GUST Mountain Bikes / Fat Tyre Bike |
| 26 inch | Older teens and smaller adults depending on frame | JUHI Hybrid and adult BlackBike models |
What Age Is a 24-Inch Bike For?
Age is only a rough guide because children of the same age can differ considerably in height.
Height is therefore a better measurement.
Within the current BlackBike range, different 24-inch models cover riders from around 135 cm to 170 cm, depending on the individual bike.
This is why we recommend checking the specific bike rather than buying purely according to age.
GUST 24-Inch Mountain Bike
| Wheels: 24 inch |
| Frame: around 30 cm |
| Gears: 21-speed |
| Published rider height: 135–160 cm / 4’5″–5’3″ |
| Especially good for: Growing riders, trails, parks and everyday riding. |
GUST 24-Inch Junior Mountain Bike
| Frame: around 30 cm junior |
| Wheels: 24 inch |
| Gears: 21-speed |
| Published rider height: 140–170 cm / 4’7″–5’7″ |
| Especially good for: Taller children, teenagers and smaller riders wanting an all-terrain bike. |
GUST 24-Inch Mountain Bike – Alternative Model
| Wheels: 24 × 2.1-inch all-terrain |
| Gears: 21-speed |
| Suspension: Front suspension |
| Brakes: Mechanical disc |
| Especially good for: Off-road use, parks, trails and everyday riding. |
| Estimated rider height: 135–165 cm / 4’5″–5’5″ (our guide, not a published figure) |
GUST 24-Inch Fat Tyre Mountain Bike
| Tyres: 24 × 4.0-inch fat tyres |
| Gears: 7-speed |
| Brakes: Mechanical disc |
| Published rider height: 140–170 cm / 4’7″–5’7″ |
| Especially good for: Riders wanting extra grip, a distinctive look and added stability. |
What Age Is a 20-Inch Bike For?
Likewise, 20-inch wheels are commonly found on children’s bikes and BMX bikes.
However, just like adult bikes, the actual frame still matters.
GUST 20-Inch Freestyle BMX
| Wheels: 20 × 2.2 inch |
| Gears: Single speed |
| Features: 360° gyro handlebars and stunt pegs |
| Published rider height: 122–160 cm / 4’0″–5’3″ |
| Especially good for: BMX riding, tricks, street and skatepark use. |
Kids 20-Inch Blue BMX Bike
| Frame: Steel |
| Wheels: 20 inch |
| Gears: Single speed |
| Published age range: 7–12 years |
| Especially good for: Neighbourhood riding, school trips and introductory BMX riding. |
| Estimated rider height: 120–150 cm / 3’11″–4’11” (our guide, not a published figure) |
Age is only a guide, though. If your child is particularly tall or short for their age, check their height before ordering.View Kids 20″ BMX
What Age Is a 12-Inch Balance Bike For?
GUST 12-Inch Balance Bike
| Wheels: 12-inch puncture-proof EVA |
| Weight: around 2.2 kg |
| Pedals: None — balance bike |
| Published age range: 2–6 years |
| Especially good for: Developing balance and confidence before moving to a pedal bike. |
| Estimated rider height: 85–115 cm / 2’9″–3’9″ (our guide, not a published figure) |
Above all, check that the child can sit comfortably and place their feet securely on the ground.View GUST Balance Bike
BlackBike Quick Size and Model Comparison
| Bike | Wheel / Frame | Published Fit | Especially Good For |
|---|---|---|---|
| JUHI 26″ Hybrid | 26″ / 14″ frame | 145–165 cm | Smaller riders / hybrid use |
| JUHI X5 Folding | 20″ / adjustable | 145–185 cm | Commuting & storage |
| JUHI Metropolitan | 700C / 41 cm | 152–175 cm | City riding |
| JUHI City Cruiser | 700C / 41 cm | About 5’4″–5’10” | Relaxed city use |
| GUST Electric Hybrid | Adult hybrid | 168–185 cm | Electric commuting |
| GUST Road Bike | 700C / 54 cm | 170–183 cm | Road & fitness |
| GUST City Hybrid | 26″ / large | 175–188 cm | Mixed road & trail |
| GUST Urban Commuter | 700C / large | 178–195 cm | Taller commuters |
| GUST Fixie | 700C / 58 cm | Approx. 178–190 cm† | Flat urban riding |
| GUST 26″ Fat Bike | 26 × 4.0″ | Approx. 172–188 cm† | Adventure / mixed terrain |
| GUST 24″ Mountain | 24″ | 135–160 cm | Kids & teens |
| GUST 24″ Junior | 24″ | 140–170 cm | Taller kids & teens |
| GUST 24″ Fat Bike | 24 × 4.0″ | 140–170 cm | Kids / teens / smaller riders |
| GUST 20″ BMX | 20″ | 122–160 cm | BMX / freestyle |
| Kids Blue BMX | 20″ | 7–12 yrs* / 120–150 cm† | Kids BMX |
| GUST Balance Bike | 12″ | 2–6 yrs* / 85–115 cm† | First bike / balance |
*Age ranges are approximate. † Estimated by us from frame size or the published age range, rather than a figure published for the model. Either way, height, inside leg and confidence tell you more than age alone.
Which BlackBike Should I Consider at 5’0″–5’5″?
So, depending on your exact height and riding style, some of the stronger options include:
- JUHI 26-Inch Hybrid Mountain Bike
- likewise, the JUHI Women’s Metropolitan City Bike
- the space-saving JUHI X5 Folding Bike
- finally, some of the 24-inch models for riders at the lower end of the range.
Inside-leg measurement becomes especially useful where two size ranges overlap.
Which BlackBike Should I Consider at 5’6″–5’9″?
In this case, you are within the fit range of several models, including:
- GUST Hybrid Electric Bike
- GUST 700C Road Racing Bike
- similarly, JUHI Women’s Metropolitan City Bike
- the JUHI Women’s City Cruiser
- JUHI X5 Folding Bike
- lastly, some 24-inch models depending on your proportions.
At this height, intended use may be more important than wheel size alone.
Which BlackBike Should I Consider at 5’10″–6’0″?
Similarly, potential options include:
- GUST 700C Road Racing Bike
- GUST Urban Commuter
- the GUST 26-Inch City Hybrid
- GUST Hybrid Electric Bike
- finally, larger-frame BlackBike hybrids.
Which Bike Should I Consider if I’m Over 6 Feet?
Taller riders should pay particularly close attention to frame size and reach. Never assume that a 26-inch or 700C bike will automatically fit.
The GUST Urban Commuter is currently listed for riders up to around 195 cm / 6’4″. Consequently, it is one of the obvious BlackBike options for taller riders.
The large-frame 700C hybrid and 58 cm fixie may also be worth considering. If you are uncertain, however, contact us with your measurements before purchasing.
Still Not Sure? Let Us Check Your Size
After all, bike sizing should not be a guessing game.
Instead, send us:
- Your height
- Likewise, your inside-leg measurement
- Also, adult or child rider
- Where the bike will be ridden
- Lastly, whether comfort, speed or off-road ability matters most
We can then point you towards the most suitable options in the BlackBike range.
Help Me Choose My Bike Browse All BlackBikes
Why Buy Your Bike From BlackBike?
Fit matters, but so does what happens after you choose your bike.
BlackBike bikes are prepared and checked by UK-based bike specialists before dispatch.
When you order through BlackBike you also benefit from:
- Free UK delivery
- UK assembly and safety checking
- 30-day money-back guarantee
- 2-year warranty
- Above all, a wide range of adult, children’s, commuter, road, mountain, BMX and city bikes
Want a New Bike Without Paying the Full Cost Upfront?
Black Bike Complete – Bike + Annual Maintenance
Black Bike Complete provides another way to get riding.
Specifically, eligible bikes are available as part of a £29.99 per month, 36-month membership. In addition, the membership includes one professional maintenance service each year.
That means you can get the bike you need while spreading the cost and having ongoing maintenance support built into the membership.
Learn About Black Bike Complete
Frequently Asked Questions About Bike Sizes
What size bike do I need for my height?
Your height is the quickest starting point, but it should be combined with your inside-leg measurement and the geometry of the individual bike. Always check the model-specific recommendation rather than relying on wheel size alone.
What height is a 26-inch bike for?
There is no single height range for every 26-inch bike, because the wheel diameter is only one measurement. In the BlackBike range, for example, one 26-inch model suits riders around 145–165 cm. Another, meanwhile, is listed for around 175–188 cm.
Is a 26-inch bike for adults?
Yes. Certainly, many adult bikes use 26-inch wheels. However, 26-inch bikes can also have smaller frames suitable for teenagers or smaller adults. So check the frame and recommended rider height.
What height is a 700C bike for?
700C wheels are used on many adult bikes, but there is no universal rider height. A 700C bike may use a small, medium or large frame, so always check the frame size too.
Is 700C the same as 28 inches?
The terms are sometimes used together when describing adult bike wheels, although tyre and rim standards can be confusing. Regardless, wheel terminology does not replace the need to check frame dimensions.
What does a 54 cm bike mean?
54 cm usually refers to a frame measurement rather than wheel diameter. For example, the current GUST 700C Road Racing Bike uses a 54 cm frame and suits riders around 170–183 cm.
What does a 58 cm bike mean?
58 cm, by comparison, indicates a relatively large frame. Similarly, the current GUST 700C Fixie uses a 58 cm large frame. If you are unsure whether it fits you, send us your height and inside-leg measurement.
What size bike should a child have?
For children, wheel size is a useful starting point. For example, BlackBike currently offers 12-inch balance bikes, 20-inch BMX bikes and several 24-inch bikes for growing riders. Height is still more important than age alone.
What age is a 20-inch bike for?
It depends on the bike, though. The BlackBike blue 20-inch BMX is currently listed for ages around 7–12. The GUST 20-inch freestyle BMX is instead specified by rider height, around 122–160 cm.
What age is a 24-inch bike for?
24-inch bikes are generally aimed at older children, teenagers and some smaller riders. Specifically, current BlackBike 24-inch models cover rider heights from roughly 135 cm to 170 cm depending on the model.
Should I buy a bike that my child can “grow into”?
A little adjustment range is useful. However, a bike that is significantly too large makes starting, stopping and controlling the bike much harder. A bike that fits now is normally more enjoyable than one chosen purely for future growth.
What if I am between two bike sizes?
In that case, send us your measurements. Your inside leg, preferred riding position and the type of cycling you plan to do will then help determine which option is better.
Can BlackBike help me choose before I order?
Yes, of course. Contact BlackBike with your height, inside-leg measurement and intended riding style, so we can help identify suitable models from the current range.
So, Are You Ready to Find Your Bike?
In short, choose the bike that fits your body and your riding — not simply the biggest wheel or the lowest price.
To begin with, explore road bikes, hybrids, commuters, mountain bikes, fat tyre bikes and BMX bikes at BlackBike. In addition, you will find children’s bikes, step-through city bikes, folding bikes and electric bikes. Also, bookmark this bike size guide, so you can check any model against your measurements before you buy.
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