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Bike Sizing Guides

Choosing the right sized bike

Making sure you choose the correct frame size is of paramount importance when buying a new bike. The correct fitting bike will be more comfortable, more efficient and more fun to ride.   We know that choosing the right sized bike can be a confusing experience, even for the most experienced cyclists – the right size frame depends on the type of bike, your height your riding style and your preference.   This guide gives our customers general advice on choosing the right sized bike. It is a guide only and we always recommend visiting our store or contacting Bob on 07 8552272 or 027 2460021 if in doubt about the size bike you need.   Read our introduction to bike sizes below, or go straight to the sizing chart for the type of bike you are purchasing.

*  How are bike frames measured

Bike sizes are determined by the frame size, based on the length of the seat tube. Most manufacturers measure from the centre of the crank axle (bottom bracket) to the top of the seat tube, where the seat post is inserted.

Unfortunately, some manufacturers measure their models from the intersection of the top tube and seat post to the crank axle, which can throw out some of the sizings, so if ever in doubt consult Bob.   Manufacturers quote sizes in different ways, some quote the size in centimeters, some in inches and some as a frame size (such as Small, Medium, Large, etc).   Although the size of frames are based on the measurement of the seat tube, it’s not just the seat tube that changes depending on the size – the entire frame changes in proportion to the frame size.

*  Matching you to the right size bike – what’s your height? 

To help our customers choose the right size bike we provide a suggested height for the various frame sizes available.   In order to accurately match the correct frame to your height it’s essential you measure your height accurately!   To best measure your height, stand against a wall with your shoes off. Keep your legs together and your shoulders back. Carefully place a pencil on top of your head and mark the wall – for best results get a helper to mark the wall for you. Then measure the mark on the wall with a tape measure.   If your height is on the cusp of the range your reach is often the deciding factor in which size to go for. To find out if you have a short or long reach measure your Ape Index (your arm span minus your height) – if you have a positive ape index then go for the larger size, if you have a negative ape index go for the smaller size.  

*  Stand over height 

Stand over height is the clearance between the top of the top tube (also known as a cross bar) and the bottom of your crotch. It’s important that you have adequate clearance in this area to avoid contact when you’re stopped and astride the bike. For road and hybrid bikes 1 to 2 inches of clearance is required, mountain bikes require 2 to 4 inches.   The sizes we recommend in our sizing charts take stand over height into consideration. So if you’ve got a close to average inside leg measurement our recommendations will be fine. If you have a short or long inside leg measurement in relation to your height we recommend talking to Bob to ensure you purchase the best fitting bike.

*  What type of bike and what type of riding?

Different types of bikes are sized in different ways. A 58cm road bike will be quite a different size to a 58cm time trial bike – so it’s important you look at the sizing chart for the type of bike that you are purchasing.   Road, triathlon and time-trial bikes are the most important to size correctly. The reach can determine feel and the frame size required, stand over height is not as important.   The type or style of riding that you do will also affect which size you need. For example a mountain biker that wants to ride more aggressively and would like a more manoeuverable bike may prefer a size smaller than they would normally take. Likewise a cross country racer that is looking for a flatter and speedier mountain bike may prefer a size larger than they would normally take. Basically there is no right or wrong when it comes to size – choosing the right bike does come down to personal preference and what you feel is comfortable and right for the riding that you do.   Remember, our sizing charts will provide accurate advice for the majority of cyclists, but for the best sizing advice we always recommend visiting our store where you can physically try the bikes in the flesh or contact Bob who will be delighted to discuss your individual sizing requirements.

* Road bike sizing chart
                        Rider Height                                                                     Frame Size Suggested
Feet and Inches                       Centimetres                                      Centimetres                    Size
4' 10" - 5 '0"                             148 - 152                                           47 - 48                              XXS
5' 0 "- 5' 3"                               152 - 160                                           49 - 50                              XS
5' 3" - 5' 6"                               160 - 168                                           51 - 52 - 53                       S
5 6" - 5' 9"                                168 - 175                                           54 - 55                              M
5' 9" - 6' 0"                               175 - 183                                           56 - 57 - 58                       L
6' 0" - 6' 3"                               183 - 191                                           58 - 59 - 60                       XL
6' 3" - 6' 6"                               191 - 198                                           61 - 62 - 63                       XXL



*  Women's road bike sizing chart  
                       Rider Height                                                                     Frame Size Suggested
Feet and Inches                       Centimetres                                       Centimetres                    Size
4' 10" - 5' 1"                             147 - 155                                           44 - 45 - 46                        XXS
5' 1" - 5' 3"                               155 - 160                                           47 - 48 - 49                        XS
5' 3" - 5' 5"                               160 - 165                                           50 - 51 - 52                        S
5' 5" - 5' 8"                               165 - 172                                           53 - 54 - 55                        M
5' 8" - 5' 10"                             172 - 180                                           56 - 57                               L



*  Mountain bike sizing chart (hardtail & full suspension)
                        Rider Height                                                                     Frame Size Suggested
Feet and Inches                          Centimetres                                      Inches                           Size
4' 10" - 5' 2"                                148 - 158                                         13 - 14                              XS
5' 2" - 5 '6"                                  158 - 168                                         15 - 16                              S
5' '6" - 5' 10"                               168 - 178                                          17 - 18                              M
5' 10" - 6' 1"                                178 - 185                                          19 - 20                              L
6' 1" - 6' 4"                                  185 - 193                                          21 - 22                             XL
6 '4" - 6' 6"                                  193 - 198                                          23 - 24                             XXL



*  Women's mountain bike sizing chart (hardtail & full suspension)
                      Rider Height                                                                       Frame Size Suggested
Feet and Inches                           Centimetres                                     Inches                           Size
4' 10" - 5' 2"                                 148 - 158                                         13 - 14                             XS
5' 2" - 5 '6"                                   158 - 168                                         15 - 16                             S
5' 6" - 5' 10"                                 168 - 178                                         17 - 18                             M
5' 10" - 6' 1"                                 178 - 185                                         19+                                  L
NOTE:
Women's mountain bikes have specific differences to men's mountain bikes.



*  Triathlon and Time Trial bike sizing chart
                     Rider Height                                                                        Frame Size Suggested 
Feet and Inches                             Centimetres                                   Centimetres                    Size
5' 0" - 5' 3"                                    152 - 160                                        49 - 50                                XS
5' 3" - 5' 6"                                    160 - 168                                        51 - 52                                S
5' 6" - 5' 9"                                    168 - 175                                        53 -54                                 M
5' 9" - 6' 0"                                    175 - 183                                        55 - 56                                L
6' 0" - 6' 3"                                    183 - 191                                        57 - 58                                XL
6' 3" - 6' 6"                                    191 - 198                                        60 - 61                                XXL



*  Children's bike sizing chart
                  Rider Age or Height                                                                Size Suggested
Age                                          Feet and Inches                                    Centimetres 
2 - 5 years                                   2' 10" - 3' 7"                                       85 - 110       Runner bikes
2 - 4 years                                   2' 10" - 3' 4"                                       85 - 100      12 inch wheel diameter
3 - 5 years                                   3' 1" - 3' 7"                                         95 - 110      14 inch wheel diameter
5 - 7 years                                   3' 7" - 4' 0"                                       110 - 120      16 inch wheel diameter
7 - 9 years                                   4' 0" - 4' 5"                                       120 - 135      20 inch wheel diameter 
9 - 11 years                                 4' 5" - 4' 9"                                       135 - 145      24 inch wheel diameter
11+ years                                    4' 9"+                                               145+              26 inch wheel diameter



*  BMX bike sizing chart
                          Rider Age or Height                                                        Wheel Size Suggested
Feet and Inches                Centimetres                 Age                                         Inches
3' 7" - 4' 0"                         110 - 122                    5 - 7 years                                 16
4' 0" - 4' 10"                       122 - 147                    7 - 11 years                               18
4' 10" - 6' 4"                       147 - 193                    11+ years                                  20

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