Info bike

THE CORRECT FRAME SIZE FOR BIKES

The most important issue influencing if you feel comfortable on your bike or not is the frame size. That is why for each bike model different frame sizes are available, usually between 2 to 4 frame sizes. The correct frame size depends mostly on your body height and step length. From this length one can calculate their frame size according to the style of bike (MTB, Trekking bike or Road bike). The frame size is measured between the top of the pedal arm and the top end of the frame. This maeasurement is either given in cms or inches. Here in our shop all bikes will be converted to cm.

Measuring your Step or Leg length

The most common made mistake when trying to find the correct frame size is measuring the step or leg length incorrectly. Because this step length is the most important factor to consider being inaccurate and measuring the step length incorrectly by only 2 or 3cms can make a huge difference and may lead to purchasing the wrong sized frame. However there is a solution to every problem! By taking the following steps it is possible for you to measure the correct step length and therefore find the correct bike for your needs.

  1. For every measurement you will need the correct tools. Ideally a tape measure or folding ruler along with a spirit level should be used. If spirit level is close at hand then a wall or book to provide a right angle will do.

  2. The next step may seem a little strange at first but for the perfect measurement necessary. Undress down to your underwear as the cut or length of your pants may influence the results greatly. Now take the spirit level or book to create a right angle to the floor and then measure from the floor up to your crutch betwwen the legs. Important is to measure right up to the TOP! This measurement is to be made without shoes. By doing this next to the wall you can be sure that the ruler or tape measure is parallel to the wall for the correct result.

  3. The resulting mesurement is your step or leg length needed to find the suitable bike for you. With this information you can now choose the frame size and bike wished using the chart below. Should you be uncertain please send us the childs height, step length and level of ability and we wil be glad to assist in finding the right bike for you. To calculate the correct frame size this measurement is to be multiplied according to the style of bike with a factor X.

Converting the step length per frame height

Given in cm, 1" = 2,54cm

Step length	Road bike	Trekking bike	Mountain bike
64 cm	43 cm (17'')	40 cm (15,5'')	36 cm (14'')
66 cm	44 cm (17,5'')	41 cm (16'')	37 cm (14,5'')
68 cm	45 cm (17,5'')	42 cm (16,5'')	38 cm (15'')
70 cm	47 cm (18,5'')	44 cm (17,5'')	39 cm (15,5'')
72 cm	48 cm (19'')	45 cm (17,5'')	41 cm (16'')
74 cm	49 cm (19'')	46 cm (18'')	42 cm (16,5'')
76 cm	51 cm (20'')	47 cm (18,5'')	43 cm (17'')
78 cm	52 cm (20,5'')	49 cm (19'')	44 cm (17,5'')
80 cm	53 cm (21'')	50 cm (19,5'')	45 cm (17,5'')
82 cm	55 cm (21,5'')	51 cm (20'')	46 cm (18'')
84 cm	56 cm (22'')	52 cm (20,5'')	47 cm (18,5'')
86 cm	57 cm (22,5'')	54 cm (21'')	49 cm (19'')
88 cm	59 cm (23'')	55 cm (21,5'')	50 cm (19,5'')
90 cm	60 cm (23,5'')	56 cm (22'')	51 cm (20'')
92 cm	61 cm (24'')	57 cm (22,5'')	52 cm (20,5'')
94 cm	63 cm (24,5'')	59 cm (23'')	53 cm (21'')
96 cm	64 cm (25'')	60 cm (23,5'')	54 cm (21'')
98 cm	65 cm (25,5'')	61 cm (24'')	55 cm (21,5'')
100 cm	67 cm (26'')	63 cm (24,5'')	57 cm (22,5'')

The information in the chart is only a guide, most bikes are available in 2 to 4 sizes therefore be sure when calculating the frame size. Should you be unsure then seek help from the manufacturers links or contact us with your step length and height.

OUR TIP:
For mountain bikes choose a smaller frame when the bike will be riden in more difficult terrain. The bike will react quicker and more agile. However the bike on faster downhill runs (in terrain) may react a bit unstable. Should one ride more on the road or on longer tours then the larger frame can be recommended. Please remember that the larger the frame the longer the top tube or bar will become. The top tube on sport bikes are usually longer, city bikes and trekking bikes are shorter to achieve a more upright seating position. Seat posts with damping or springs require extra room between the seat and top tube, in which case a smaller frame size can be considered.

Adjusting the seat height

The correct seat height can be found easily. Adjust the seat post so high so that when seated the legs with the your heel in the pedal, can be straightened out. That makes sure that when pedaling (the ball of the foot is on the pedal not the heel) that the leg will not be over stretched but still takes advantage of the entire legs length. For safety reasons (being able to reach the ground quickly) one can adjust the seat a little bit shorter. In addition the seat can be adjusted a few cms forward or backwards to help find the perfect position for each individual person. Should that not be enough one can achieve this by adjusting the head angle  or by replacing the head with a shorter or longer one. That also goes for the handle bar. Remember that generally a more angled body position on mountain and road bikes is normal and a more upright position for trekking bikes to bring more comfort.

As general rule for the correct seat height is 0,88 X step length.