Richard Marson Cycles

To ride your bike comfortably you should be able to keep your foot flat on the pedal throughout its rotation and be able to touch the ground. General Guidelines.

Your Inseam and Frame Size To measure your inseam, get a pencil and a book that has a binding about 2 inches thick. Take your shoes off and stand facing a wall. Put the book between your legs, with the binding facing up and your feet about 6 inches apart. Hold the book firmly under your crotch - you should feel the same amount of pressure as sitting on your bike saddle. Make sure your legs are straight, and hold the book square against the wall. Mark the spot on the wall at the top of the book. Measure the distance from the floor to the mark - this is your inseam. For accuracy, repeat the measurement several times and calculate the average. You may need to interpolate for height and shoe size. Shoe size is used to help calculate appropriate top tube. EXAMPLE: Your measurements are inseam of 32 inches, height 5'9" and shoe size 9.5. Your inseam indicates that you need a seat post of 55 cm center to top. Subtract 1.5cm to get center to center of 53.5. Your height and shoe size indicate that your body is proportioned more in the torso than legs, so you will need a longer stem or top tube of about 56. If the frame you want is 55c/t, but has a top tube of 55 - just add 1 cm to your stem size. Frame Size Frame size refers to the length of the frame’s seat tube. Pro frames are measured along the seat tube in one of two ways, center-to-top (C-T) or center-to-center (C-C). C-T measures the distance from the center of the bottom bracket to the top of the top tube or seat lug (See image bellow). C-C measures from the center of the bottom bracket to the center of the top tube. Since C-T measures to a point higher on the frame, a frame measuring 55cm C-T would also measure roughly 53.5–54cm C-C, a difference of 1–1.5cm. To size your C-T road frame, we use a guideline of .67 x inseam length. For example, if you have an 85cm inseam, your C-T frame size would be .67 x 85cm, or 57cm. LeMond’s formula, from his former coach, Cyrille Guimard, establishes C-C size by the formula .65 x inseam length, which yields virtually the same frame size when you add the 1–1.5cm difference between C-C and C-T. Larger riders (6'0" and up) may find that this formula puts them on a too small, and uncomfortable, road frame. A taller cyclist who wants a more comfortable frame may be better off selecting a frame 27–28cm less than inseam length, C-T. For a mountain bike, we start by recommending a frame in the range of 10–12cm smaller than you take in a road frame. For example, if you ride a 55cm C-T road frame, look for a 43–45cm (17–18") C-T mountain frame. In many ways, though, it is more important to fit a mountain frame by the top tube length needed, rather than by the seat tube length. For instance, you might be able to get to the proper frame clearance, saddle height and neutral knee position (see below) on either a 17" frame or a 19" frame. Yet the 19" frame will likely have a top tube 1" longer than the 17" frame, which changes your stem length accordingly. Or, one manufacturer’s 17" frame may give you a 22" top tube, while the next one’s 17" gives you a 22.8". More on this below… just make sure that you’ll be able to work out your top tube and stem length for a given frame. Saddle Height With the right frame size, you’ll be able to set your correct saddle height, which will be within a centimeter of .883 x inseam length, measured from the center of the bottom bracket to the low point of the top of your saddle. This allows full leg extension, with a slight bend in the leg at the bottom of the pedal stroke. LeMond recommends that you then shorten this length by 3mm when using clipless pedals. Also, you might consider a slightly taller saddle height if you ride with your toes down and your heel raised. Most importantly, make any changes in saddle height gradually, and give your body time to adapt to the new position Neutral Knee Position Next, put your bike in a stationary trainer, raising the front wheel to level the bike. Check your position with a video camera or mirrors in front and to the side, or with the help of a friend. Position your cleats with the ball of your foot directly over the pedal axle, and in line with any natural "toe-in" or "toe-out" foot position. Warm up by riding easily for 8–10 minutes. Then, as you continue to look ahead, slowly stop pedaling, and bring the cranks to rest at horizontal, parallel to the ground. Check the position of your forward knee relative to the pedal spindle —for a "neutral knee position," you’ll be able to drop a plumb line from just below the front of the forward kneecap, and have it bisect the pedal spindle and ball of your foot below. Remember to not raise or drop your heel or hip as you check this. Then, move the saddle fore or aft, as needed, to achieve this neutral position. The neutral knee position serves as a good starting point for most cyclists, though many adjust it from here: long distance (stage) racers and mountain bikers often move the saddle back by 1cm or more, for power, and sprinters may move it forward, “getting on top of the gear” for quick acceleration. One more note on frame size and geometry: if you cannot move the saddle back far enough to get your knee to the neutral position, you should look for a frame with a more relaxed seat tube angle, or consider a slightly larger frame; if you have trouble moving the saddle forward enough, look for a steeper seat tube angle on your next frame, or consider a smaller frame. For most frames, a seat tube angle shallower by 1° moves the seat lug 1cm back, relative to the bottom bracket. Finally, recheck your saddle height. If you’ve moved your saddle forward or back, you’ve effectively shortened or lengthened your saddle height, and will need to readjust it.                      Top Tube and Stem Length Next, dial in the correct "reach" to the bar, or horizontal fit. Proper reach gives you easier breathing, better neck and lower back comfort, and better weight distribution and bike handling. That "ideal position" varies here more than anywhere else for cyclists, depending on riding style, flexibility, body proportions, and frame geometry, among others. And, your upper body position will evolve with more hours in the saddle. That is, you may find that you develop a lower, longer position as your fitness and flexibility improve. As Phinney notes, though it may be difficult to achieve a truly flat back, we cyclists should all strive to be “longer” across the top of the bike. Unfortunately, there is no formula for sizing the top tube and stem that works as well as the inseam method. One indicator comes from glancing down at the front hub while riding in the drops; your view of the the front hub should be obstructed by the handlebar. LeMond recommends that your elbows, bent at 65–70° with your hands in the drops, should be within an inch or two of your knees at the top of your stroke. Measure your current bike’s top tube and stem. Then, decide how you’d like to alter that fit; add the top tube length to the stem length to get your overall top dimension. The very reason we stock stems in 1cm increments, from 7cm to 14cm, is just to let you dial in your best top tube and stem length.