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Bike Sizing Guide

Bike Size Guide

What size bike frame do I need?

Choosing the right bike frame size for your new bike makes all the difference; because if the fit is good you will be more comfortable when cycling, the handling will be easier and you will be able to ride more efficiently. In this bike size guide we will explain how you can use the bike size charts and bike sizing calculator to get the ideal bike frame size.

If you want to know what size bike you need, all you need to do is match your height and inside leg measurement to the frame size recommended by the manufacturer in their bike size charts. To make is easier to find the right bike frame size you can use our handy  bike size calculator.


Do sizes vary for different types of bikes?

Road bikes and mountain bike frame sizes are slightly different and the units used in bike sizes vary depending on type and brand. Road bike sizing is usually given in centimetres, while mountain bike frame sizes are quoted in inches. Fortunately, our  bike size calculator takes away the guesswork from bike frame size as it suggests mountain bike frame size and road bike frame size in either inches or centimetres alongside manufacturers bike size charts.

Many bike manufacturers will quote bike sizes as S, M, L or small, medium or large etc. on some or all their models. Kids bike sizes are usually based on wheel size.


MTB vs Road bike sizing

How do I choose the right size bike?

In this bike size guide we make choosing the correct bike frame size easy. All you need to do is measure your height and your inside leg (inseam) and then enter those measurements into our  bike size calculator.

Measure your height

Simply stand on a flat surface, upright against a wall with your legs together and shoulders back. Make sure you take your shoes off. Place a pencil on top of your head and holding it parallel to the floor make a little mark on the wall.

Measure your height for bike fit

Measure your inside leg

Stand with your back against a wall (no shoes). Place a book or ruler between your legs at your crotch. Get a friend to measure from the floor to the top of the book/ruler, making sure it is level.


Measure your inside leg for bike fit

Typical Bike Sizing Chart

Height

Inside leg

Road bike size

Mountain bike size

152cm / 5'.0"

71cm / 28"

48cm (XX Small)

15" (X Small)

160cm / 5'.3"

75cm / 29.5"

51cm (Small)

16" (Small)

170cm / 5'.7"

79cm / 31"

54cm (Medium)

17" (Medium)

175cm / 5'.9"

83cm / 32.5"

56cm (Large)

18" (Medium)

180cm / 5'.11"

85cm / 33.5"

57cm (X Large)

19" (Large)

188cm / 6'.2"

89cm / 35"

60cm (XX Large)

20" (Large)

196cm / 6'.5"

93cm / 36.5"

63cm (XXX Large)

21" (X Large)

Can I use the bike size calculator for women’s specific bikes?

Yes, typically women’s specific bikes have different bike frame sizes to unisex bikes but they are sized in the same way. Women tend to have shorter upper bodies than men so the frames are shaped differently. 

Women's bikes tend to have shorter top tubes compared to a similarly sized unisex bike. This makes the bike slightly shorter than a unisex bike so female cyclist will feel less stretched out on women’s bike.

As this doesn’t affect the seat tube length (saddle height) or stand-over clearance, our bike size calculator is suitable for both unisex and women’s specific bikes and the information in this bike size guide is relevant to women’s road bike sizes as well as women’s mountain bike sizes.

Women specific bike sizing

What size bike should I choose if I am between sizes?

Sometimes our bike sizing calculator will recommend two different bike frame sizing options. This means that both the larger and smaller road bike frame size or mountain bike frame size recommended will be suitable It is a personal choice but, if you are unsure, there are a couple of rules of thumb:

Road bikes - choose the smaller size. This is because it is easier to make a small road bike bike bigger (by raising the saddle or fitting a longer stem) than it is to make a big road bike smaller.

Mountain bikes - choose the larger size. You don't want to feel too cramped on an MTB and lengthening the stem on a smaller bike can adversely affect the handling. You will better off with a slightly larger bike and shortening the stem if necessary, as this often improves handling.

What bike to choose when between sizes

Bike Size Calculator

Your mountain bike size is:

Frame (inches):16/17
Frame (size):Small / Medium

Your road bike size is:

Frame (cm)
Frame (size)


*For model specific sizing please check the product page.

**Please note all sizing information is to be used as a guide only. This is because bike sizes can vary for different brands and models. If you are unsure which size bike will be best for you, our bike specialist team are here to help. Call us on 01792 346501, chat with Live Help or email info@tredz.co.uk and we will be happy to assist you.