transformparts Bicycle Bike Layback Seatpost Seat Post 25.4 350mm

Product Information

Though some brands like to play exception to the rule, the majority of bikes are designed to fit a seatpost of either 31.6mm or 27.2mm. At 300mm in length, the Enve seatpost is available in 0mm, and 25mm-offset versions. While quite a few carbon posts have a metal clamp head bonded on the top, the Enve post is carbon through and through. If it has a round seatpost, however, you are likely to have far more options – but diameter becomes all-important. The two standard diameters are 27.2mm and 31.6mm and all of the seatposts featured in the guide will fit one of those two sizes, while some have more options in between. Aero road bikes come with aero seatposts. These are flatter and designed to channel air more seamlessly, limiting the resistance that slows you down. Aero posts: While most posts (and seat tubes) are circular in cross-section, many manufacturers are now making aero posts for road and TT racing, with an elliptical ‘blade’ cross-section which offers improved aerodynamic performance by offering less frontal area to the wind. However in the case of ‘full’ aero seatposts you will require a frame with a matching seat tube, which limits the options when it comes to changing or upgrading. Some manufacturers get over this by offering posts with a shaft featuring a ‘normal’ bottom half, with the part above the seat clamp then shaped to a bladed aero profile.

There are very few at the moment but some manufacturers have cradles which can only be used with their corresponding saddles. These will have a patented rail system which is unique to that manufacturer and cannot accept any other saddle.All seatposts clamp to the saddle in their own unique way, and have different methods of allowing the saddle to point slightly down, slightly up or remain flat. Like handlebars, wheels, and nearly all other bike components, seatposts come in a variety of materials, the most common being aluminium and carbon fibre. As always, carbon commands a higher price tag, but it usually weighs less and can be constructed in a way that dampens more vibration while maintaining directional stiffness in a way that will benefit the rider.

A key factor is the diameter of the seat post. This must directly match the internal diameter of the seat tube of your frame. The majority of modern seat posts are 27.2mm, 30.9mm or 31.6mm wide, with the latter often described as oversized.If you don't feel your bike needs to be any more comfortable, and you're not fussed about 100 grams, then aluminium seems like a smart choice. If you want to drop the weight or add some cushion, look to spend more. Some bikes even go as narrow as 25.4mm, Cannondale being a case in point. A skinnier post will provide a bit more flex, and therefore a slightly more comfortable ride, while a fatter one will be more robust and add stiffness for additional power transfer. When it comes to cancelling vibrations, there are several steps brands take to aid this in frame construction: using thin seatstays; placing the seatpost clamp lower down so that more seatpost is exposed (allowing for more flex); and using a narrower seatpost A carbon seatpost is effectively an additional step; a cherry on top.