The best way to determine the frame size or frame height is to measure your inner leg length or inseam length. The measurement is taken from the sole of the foot to the crotch. As a further help we have included a few tables with approximate guide values ​​below. Children’s and youth bikes age of the childHeight in cmwheel size 3+ years95 to 12012″ to 14″ 4+ years105 to 12516″ 5+ years110 to 13018″ 6+ years120 to 14220″ 8+ years130 to 16024″ 10+ years140 to 17026″ Road bike / Gravel bike / Singlespeed: The inner leg length is multiplied by 0.665. The frame height of the triathlon bike is lower. Height in cm Frame height road bike / gravel bike / single speed in cmFrame height triathlon bike in cm 155 to 16548 to 5146 to 48 165 to 17051 to 5348 to 50 170 to 17553 to 5550 to 52 175 to 18055 to 5752 to 55 180 to 18557 to 6055 to 57 185 to 19060 to 6257 to 60 190 to 19562 to 6460 to 62 195 to 200from 64from 62 Trekking and city bikes : here the inner leg length is multiplied by 0.66. For a cross bike , multiply by 0.61. This results in the frame height in cm. Height in cmFrame height for trekking and city bikes in cmCross bike frame height in cm 155 to 165 47 to 5041 to 43 165 to 17050 to 5243 170 to 17552 to 5543 to 48 175 to 18055 to 5848 to 53 180 to 18558 to 6153 185 to 19061 to 6353 to 61 190 to 20063 to 6661 to 63 Mountain bike hardtail and full suspension: The inside leg length is multiplied by 0.22. Height in cmFrame height in inches 155 to 16535 to 38 165 to 17038 to 41 170 to 17541 to 43 175 to 18043 to 46 180 to 18546 to 48 185 to 19048 to 53 190 to 19553 to 56 195 to 20056 to 58 General note : If the value of the frame size is between two sizes, the following applies as a guide: – If you are a sporty rider, then the smaller frame – If you are a touring rider, then the larger frame. Please note that the tables only represent guideline values .