A variety of diameters, lengths and materials - our shop sells seat posts for road bikes; here you'll certainly find the right post for your road bike. Whether it has to be a straight seat post or one with an offset head is determined by the sitting angle and the dimensions of your legs. Adjusting a wrong frame size through the road bike seat post can damage your efficient sitting position, or in the worst case, your knees. The so-called offset or setback can also be bad for seat posts used in against-the-clock races and triathlon. Not all saddle clamp systems are compatible with every saddle rail diameter. Clamping heads with side clamping often come in the standard version for 7 mm seat rails and need to be modified with optional parts to fit the thicker carbon rails. Lightweight road bike carbon seat posts can easily weigh less than half of a low-cost aluminium seat post, but a high-end seat post isn't exactly cheap either. Aside from the lightweight design and visual appearance, there are occasionally more specific requirements: Drop-shaped seat posts that fit only in suitable frames, or seat caps / mast toppers and heads for frames with an integrated seat tube. Round shaped seat tubes with an inner diameter of 27.2 mm, 30.9 mm or 31.6 mm are much more common, thus you'll find a larger selection for those sizes. Whereas the larger diameters were popular these past years because of higher frame stiffness, smaller diameters are now experiencing a comeback due to improved comfort.