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Silvester Brothers Cycle Ltd workshop

Welcome To Our Bike Size Guide

Choosing the right size bike is paramount; you will be more comfortable, confident and enjoy your riding much more. In this bike size guide, you will know what measurements you need and which size bike you need. Or, our kids' bike size guide details what size they will need before you shop.

How Do I Choose The Right Bike Size?

Bikes are usually measured by the length of the seat post tube, however children's bikes are normally by wheel size - the tube on the frame where the seat post slides in to.

  • Most adult bikes give sizes in either centimetres, inches or size increment e.g. Small, Medium, Large etc.
  • Children’s bikes are normally measured in wheel sizes e.g. 12inch, 14inch, 16inch ect.
The charts below show the size of bike and the recommended riders inside leg, hight and age.

Other measurements that are important are stand over height and saddle pedal position.

Standover height.

Stand over the frame, with you bottom just in front of the saddle as pictured. The ideal distance between groin and frame is 2”.
This measurement is not applicable to ‘low step’ frames or ladies frames.

(This measurement is sometimes trickly to work out without the bike in front of you. However, a lot of the size charts on the product pages give the geometry of the bikes like the one below.)

Pedal Position

Once you have your bike it's important to check the saddle height.

Get on the bike, either with someone holding it or with the handlebar end propped against a wall to help keep the bike straight without you and it falling over!

Put your feet on the pedals and pedal backwards very briefly until one pedal is at its lowest position, or preferably in line with the frame seat tube. The leg on the pedal (at its lowest position) should be ever so slightly bent as shown when the heel is placed on the pedal. It should neither be completely straight or too bent (as pictured).

What Measurements Do I Need?

There a several key body measurements it is wise to know before choosing your bike, but the main two are your inside leg measurement and your height.

Bike Size Guides

Kids' Bike Size Guide

Wheel Size

Age Group

Inside Leg

12 Inch Wheel

3 Years Plus


14 Inch Wheel

4 Years Plus


16 Inch Wheel

5 Years Plus


18 Inch Wheel

6 Years Plus


20 Inch Wheel 11 Inch Frame

6 Years Plus


20 Inch Wheel 13 Inch Frame

7 Years Plus


24 Inch Wheel 12 Inch Frame

8 Years Plus


24 Inch Wheel 13 Inch Frame

8 Years Plus


24 Inch Wheel 14 Inch Frame

8 Years Plus


26 Inch Wheel 14 Inch Frame

9 Years Plus


26 Inch Wheel 17 Inch Frame

10 Years Plus


Mountain Bike Size Chart

Inside Leg Range

Frame Size

24 - 29" (61 - 74cm)

14" (35.56cm)

25 - 30" (64 - 76cm)

15" (38.1cm)

26 - 31" (66 - 79cm)

16" (40.64cm)

27 - 32" (69 - 81cm)

17" (43.18cm)

28 - 33" (71 - 84cm)

18" (45.72cm)

29 - 34" (74 - 86cm)

19" (48.26cm)

30 - 35" (76 - 89cm)

20" (50.8cm)

31 - 35" (79 - 89cm)

21" (53.34cm)

32 - 37" (81 - 94cm)

22" (55.88cm)

33 - 37" (84 - 94cm)

23" (58.42cm)

Road Bike Size Guide

Inside Leg Range

Frame Size

27 - 29"


28 - 30"


29 - 31"


30 - 32"


31 - 33"


32 - 34"


33 - 35"


34 - 36"