Complete Bike Frame Size Guide - Average Joe Cyclist

Our complete bike frame size guide will show you how to figure out the correct bike frame size for adults and kids – for hybrid and mountain bikes, and for road bikes too. This guide includes all you need to know about bike frame measurement, and includes bike frame size charts for adult bikes (hybrid, mountain and road) and for kid’s bikes too. This guide also includes advice on whether you should consider a women-specific bike. The guide concludes with a useful video showing how to measure for correct bike frame size.

This boy has outgrown his bike, which is causing him to cycle in an inefficient way. He is also putting excessive strain on his knees. Bike size guide
This boy has outgrown his bike, which is causing him to cycle in an inefficient way. He is also putting excessive strain on his knees

Related Post: How to Find the Right Height and Setback for Your Bike Saddle

Contents of this Post

  • The 3 Crucial Things to Get Right When You Buy a Bike
    • Kind of Bike
    • Buy it from the Right Place
    • Buy a Bike with the Right Size Bike Frame
  • Problems with Buying the Wrong Size Bike Frame
    • You Should be Able to Stand Over Your Bike
    • Related Post: How to Buy Used Bikes on Craigslist
  • Bike Frame Size Measurement
    • Height, Inseam Length and Reach – the 3 Vital Measurements for Bike Frame Size Measurement
      • Height and Inseam Length
      • Your Reach – Do you Have a Good Ape Index?
  • Two Different Bike Frame Size Systems
  • Bike Frame Size Chart for Adult Bikes – Hybrid Bikes, Mountain Bikes, and Road Bikes
  • Do You Need a Women-Specific Bike?
    • People who May Benefit from a Women-Specific Bike
      • Men can Also Ride Women-Specific Bikes
  • Bike Frame Size Chart for Children’s Bikes
  • Important Points to Keep in Mind when Choosing a Bike Size for Your Child
    • Age Range is Not the Whole Story
    • Height and Inseam are the Key Factors
    • Don’t Cheap Out on Kid’s Bikes
  • Video Showing How to Measure Bike Frame Size

Please note that as an Amazon Associate I earn from qualifying purchases.

Bike frame size is very important. In fact, there are three crucial things to get right when you buy a bike. One of these is your bike frame size. If you get this wrong, the bike will NEVER be right for you.

Bike Frame Size Guide. This is the central bike frame and the tubes. If this is the wrong size, your bike will never be right for you
This is the central bike frame and the tubes. If this is the wrong size, your bike will never be right for you. On most bikes, the size of the frame will be printed somewhere on this part of the frame

The 3 Crucial Things to Get Right When You Buy a Bike

Kind of Bike

It is important to buy the right kind of bike for the type of cycling you plan to do – here’s a guide to the different kinds of bikes.

Buy it from the Right Place

Always try to buy your bike from a bike shop, or buy a good used bike (get advice on buying used bikes here). Or, buy a bike that has great reviews online. However, don’t buy a bike from a department store. These bikes have poor components and are often assembled by people with no bike knowledge.

Our Picks for the 7 Best Budget Bike Computers
No. 1: CatEye Velo 9
No. 1: CatEye Velo 9. About $30. Please click here for current best price on Amazon.
No. 2: Bryton Rider 420E Wireless GPS computer. About $155. Please click here for current best price on Amazon.
No. 3: Lezyne Macro Cycling GPS Computer
No. 3: Lezyne Macro Cycling GPS Computer. About $200. Please click here for current best price on Amazon.
CatEye Strada Wireless
No. 4: CatEye Strada Wireless. About $65. Please click here for current best price on Amazon.
CatEye Padrone Cycle Computer No. 5: CatEye Padrone Cycle Computer. About $55. Please click here for current best price on Amazon.
No. 6: Sigma Sport BC 5.12. About $22. Please click here for current best price on Amazon.
No. 7: CatEye Velo 7. About $30. Please click here for current best price on Amazon.

Buy a Bike with the Right Size Bike Frame

Buy the right size bike frame. To find out how to do this, read this post!

Use this post to get your bike size right. This young woman's bike is just a tiny bit too small for her. As you can tell by how much her knees are bending, even on her right leg. She could adjust this a bit by raising her saddle. Or, she could just read this post and get the right size bike. The advantages of having a correct size bike include less knee pain, enhanced safety, and more comfort
Use this post to get your bike size right. This young woman’s bike is just a tiny bit too small for her. As you can tell by how much her knees are bending, even on her right leg. She could adjust this a bit by raising her saddle. Or, she could just read this post and get the right size bike. The advantages of having a correct size bike include less knee pain, enhanced safety, and more comfort

Related Post: 7 Great Budget Bikes You Can Buy on Amazon

Problems with Buying the Wrong Size Bike Frame

You can change all the other components, but you are stuck with the kind of bike and the bike frame size. If you make the wrong choices with these, you will end up having to sell the bike and start again. Or you will just find cycling unsafe and uncomfortable.

I have made the mistake of buying a bike that was too big, just because I loved the look of the bike. Big mistake! I could never get completely comfortable on the bike, and eventually I had no choice but to sell it. I am embarrassed to admit that I actually made this mistake twice! (I’m just a sucker for a pretty bike.) Buying the wrong size bike is an expensive, time-wasting mistake – and it can even be dangerous.

Bike Frame Size Guide. To measure the bike frame size, measure the length of the seat tube
To measure the bike frame size, measure the length of the seat tube

You Should be Able to Stand Over Your Bike

If your bike has the right frame size, you will be able to comfortably stand over the cross bar. You will be able to stop safely, rather than having to fall helplessly sideways until your foot hits the ground!

This bike is a little too large, so the rider can only just stand over it. She would need a bike at least one size smaller to be completely comfortable
This bike is a little too large, so the rider can only just stand over it. She would need a bike at least one size smaller to be completely comfortable. This is Maggie, modeling with my mountain bike!

If your bike is too small, your knees and back may start to hurt, and you won’t be able to use your leg power efficiently (plus you may look funny – a bit like a penguin!). You will be much more likely to develop cycling knee pain. And most likely you will quit cycling and never get to experience the amazing health benefits of cycling.

Related Post: How to Buy Used Bikes on Craigslist

Before you lay your money on the table and take a bike home, be sure to measure the standover height and make sure you can comfortably stand over it. You measure it at the mid point of the cross tube, as shown below. That measurement must be less than the measurement of your inseam, otherwise, you are in for a world of hurt!

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Before you lay your money on the table and take a bike home, be sure to measure the standover height and make sure you can comfortably stand over it.
Before you lay your money on the table and take a bike home, be sure to measure the standover height and make sure you can comfortably stand over it.

Bike Frame Size Measurement

Bike frame sizes are based on the height of the bike, measuring the length of the seat post tube – the part of the bike that the seat post (and saddle) slide into. This measurement is given in metric (cm) for road bikes, and imperial (inches) for mountain bikes. On most bikes, the size of the frame will be printed somewhere on this part of the frame.

At the end of this post, you can view a short video showing how to measure bike frame size.

Related Post: 7 of the Best Budget Indoor Bike Trainers

Height, Inseam Length and Reach – the 3 Vital Measurements for Bike Frame Size Measurement

Height and Inseam Length

The two most important measurements to know are your height, and your inseam length (the distance from your crotch to the end of your pant leg). Of these two lengths (height and inseam), inseam is the most important.

Bike Frame Size Guide. This is your inseam length - one of the three important measurements for choosing the right bike frame size
This is your inseam length – one of the three important measurements for choosing the right bike frame size

The reason the inseam length is the most important is because it determines your stand-over height. For example, if a bike has a stand-over height of 27 inches, and you have an inseam length of 29 inches, you will be able to stand over the bike, and the cross bar will not hurt you if you have to stop suddenly. (Obviously this is less important with step-through style bikes that do not have a cross bar.)

Also, this bit of clearance will enable you to safely and easily hop off the bike when you need to.

Bikes Frame Size Guide. This graphic illustrates the concept of stand-over height
This graphic illustrates the concept of stand-over height

For road bikes you need to have about 1 to 3 inches of distance between the bar and your crotch; for mountain bikes it is safer to have an inch or two more.

Related Post: 9 of the Best Road Bike Saddles

Your Reach – Do you Have a Good Ape Index?

Your reach measurement becomes important if your height and inseam measurements put you in between sizes. In that case, use your reach measurement to decide.

You need to know if you have a long or short reach, which means you need to find out your “ape index” (which is your arm span compared to your height).

  • If you have a positive ape index (your arm span is greater than your height) then you have a long reach and you should probably go for the larger of the sizes.
  • If you have a negative ape index (your height is greater than your arm span) then you have a short reach and you should probably go for the smaller of the sizes.
Bike Frame Size Guide. Your ape index will help you decide what bike frame size you should choose - especially if you on the border line between two sizes
Your ape index will help you decide what bike frame size you should choose – especially if you are on the border line between two sizes

For example, say you have an arm span of 160 cm and a height of 160 cm. This would mean your arm span is exactly the same as  your height. So, you have an ape index of 1, and therefore an average reach. However, if your arms are shorter, you have a short reach, so if you are between frame sizes, go for the smaller frame size.

Two Different Bike Frame Size Systems

Just to make it a little more challenging, there are two different bike-sizing systems. So, there’s one system for road bikes, and then a different one for mountain bikes and hybrid bikes. Sizes are given in metric (cm) for road bikes, and imperial (inches) for mountain bikes.

You can figure out your bike frame size with the Bike Frame Size Charts below.

Sizing is different with mountain bikes
Sizing is different with mountain bikes

Bike Frame Size Chart for Adult Bikes – Hybrid Bikes, Mountain Bikes, and Road Bikes

Complete Bike Frame Size Guide. Chart Showing Adult Bike Sizes for hybrid, mountain, and road bikes
Chart Showing Adult Bike Sizes for hybrid, mountain, and road bikes

Even with the right frame size, if you are planning to do a lot of cycling, you should still get your bike fine-tuned with a professional bike fitting, if you can afford it. If you are buying a new bike, try to find a bike shop that offers some help with bike fitting. Some of them are especially good with this, and will give you a professional level of help. (Many of the smaller bike shops cannot afford this, however.)

Getting a well fitting bike will protect you against back pain or cycling knee pain.

Related Post: How to Choose the Right Bike Saddle

Do You Need a Women-Specific Bike?

On average, women tend to have longer legs and shorter torsos than men of equivalent height. Women-specific bikes offer details such as the following to accommodate women’s bodies:

  • smaller frame sizes
  • shorter top tubes
  • narrower handlebars
  • female specific-saddles and
  • smaller brake handles.

However, you are unique, and a women-specific bike may not be right for you, even if you are a woman. The bike you choose should be the perfect fit for you individually, regardless of gender.

Products We Recommend for Women's Cycling Health
Beroy Padded Bike Bib Shorts. About $36 - Please click for current Amazon price
Terry Padded Women's Bike Shorts. Around $60. Please click here for current price on Amazon
Bike Fit 2nd edition: Optimise Your Bike Position for High Performance and Injury Avoidance. Please click here to view the best current price on Amazon
ISM PR Series Noseless Bicycle Saddle
ISM PR Series Noseless Bicycle Saddle. Noseless saddles have been proven to reduce saddle pain. Around $160. Please click here to see the best current price on Amazon
Selle Anatomica Saddle. Leather saddle, made in the USA, renowned for comfort. Around $200. Please click here to view current best price on Amazon

People who May Benefit from a Women-Specific Bike

The following categories may do better with a women-specific bike:

  • You are a man or a woman who is shorter than about 5 ft 5 in (165 cm), or
  • You are a man or a woman who has shorter arms, or
  • You are a man or a woman who has felt too stretched out on unisex bikes before.

Try them out and see what works for you. I have known women who have been absolutely ecstatic on riding their first women-specific bike, because for the first time they felt like the bike really fitted them. On the other hand, other women find no benefit in them.

Supplements that We Recommend for Cyclists Trying to Lose Weight
Precision Hydration Fuel Gel with 30 grams of carbs to fuel your long bike rides. Please click here to see the current best price on Amazon
Nuun Sport Electrolyte Tablets. Sugar-free and sweetened with Stevia. Please click here for the current best price on Amazon
Dymatize ISO 100 Whey Protein Isolate Powder, Chocolate Peanut Butter Flavor. High protein with low carbs and fats. Please click here for current best price on Amazon
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Men can Also Ride Women-Specific Bikes

Also, bear in mind that if you are a man and you choose a woman-specific bike, that is just fine – and no one needs to know! The reality is that the average male height in some countries is shorter than the average female height in others. For example, average male height in Indonesia is 5 ft 2 in, while average female height in The Netherlands is 5 ft 7 in (must be all that cycling that makes them grow so tall and strong)!

So obviously, we cannot really generalize too much about this matter. Everyone is unique.

Bike Frame Size Chart for Children’s Bikes

Bike Frame Size Guide. Chart showing sizes for kids bikes, based on child's age and height
Chart showing sizes for kids bikes, based on child’s age and height

Kid’s bikes are measured and sized differently. Often they are categorized in age ranges and wheel sizes, as you can see from the table.

Related Post: How to Teach a Child to Ride a Bike in 7 Simple Steps

Important Points to Keep in Mind when Choosing a Bike Size for Your Child

Bike Frame Size Guide. On a bike of the right size, a child can get out and have fun!
On a bike of the right size, a child can get out and have fun!

Age Range is Not the Whole Story

Don’t rely on an age range to pick a bike size for your child. There are tremendous variations based on individual differences. Just as with gender, age does not necessarily predict height.

Height and Inseam are the Key Factors

Height and inside leg measurement remain the key factors. Keep this in mind and make sure your child can comfortably stand over his or her bike.

This is especially important for safety for kid’s bikes – they need to be able to stop safely, and get off safely. Don’t put them off bikes for life by making their early experiences scary. Which brings us to the next point.

Don’t Cheap Out on Kid’s Bikes

Do not buy a bike that is a bit bigger, thinking your child can grow into it! The bike needs to fit from the get-go, so that your child does not get hurt or frightened. Unlike a jacket, a child can actually fall off a bike, so buying big is not a good idea.

You may be able to extend the useful life of your child’s bike by raising the saddle when he or she grows. But you must have the right frame size to begin with.

Bike frame size guide: Set the foundation for a lifetime of happy cycling by buying the right bike frame size for your child!
Set the foundation for a lifetime of happy cycling by buying the right bike frame size for your child!

Once you have a perfectly fitted bike, use it to get Perfectly Fit! Click here for my Complete Bike Fit Cyclist Training Plan.

Our Picks for the 7 Best Bike Computers
Cateye Velo 9 - around $30 - click to check current price on Amazon
Garmin Edge 530 - around $300 - click here to check current price on Amazon
Bryton Rider 15 Neo - around $70 - click here to check current price on Amazon
Garmin Edge 130 Plus - around $200 - click here to check current price on Amazon
Garmin Edge 840 - around $450 - click to check current price on Amazon
CatEye Strada Wireless - around $65 - click here to check current price on Amazon
Cateye Padrone - around $55 - click here to check current price on Amazon

All of the above should be used as a guide. There is no substitute for trying out the bike and taking it for a good test run. Good luck with finding your perfect bike!

Video Showing How to Measure Bike Frame Size

As an Amazon Associate I earn from qualifying purchases.

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