Ritchey company used to be quite good, but I haven’t bought anything from them for a while – and they don’t seem to be making any 25.4 mm sized ones. In short, no. Seatposts are an area where bike manufacturers seek to make gains in weight, aerodynamics and comfort – so there are a whole range of different types that come with different bikes. Measuring the circumference of the post and dividing by Pi is a good method. There are even circumference tape measures to do it. That means that it's much easier and safer to put the post down at speed as you don't need to move your There are a number of advantages to this, namely that the body of the post, which needs to cope with very heavy loads, doesn’t also have to be airtight and so lower-friction seals can be used for a lighter action.

For easier managing, table 2 gives an overview of seatpost diameters most commonly used on modern bicycles (from the end of the 20th century to now). Seatpost diameters most commonly used on “modern” bicycles. How to measure the seatpost diameter? The easiest and most accurate method is to use calipers (Vernier, or digital), as shown in picture 2. Measuring seatpost diameter using calipers. The Fox DOSS has three settings, one fully up for pedalling, 40mm down for more technical but still pedally Most of the best road bike saddles use a two-rail system, however not all two-rail saddles are compatible with all seatposts. Saddles with alloy rails will have 7mm, round rails, while most carbon-railed saddles have 7x9mm oval rails. position posts as they don't require you to 'hover' over the saddle. Many users favour specific posts, andcradles, have a minimal effect on performance. Changing a Seatpost for Comfort vs Altering the Bike Fit To figure out how long a drop you can use, measure your existing seatpost from the saddle rail to the top of seat collar, then compare this to the length of the dropper post from the saddle rail to below the post’s collar. The Crankbrothers Highline dropper seatpost is designed for cross-country cycling and gravel riding, so it comes in a narrow 27.2mm diameter and with relatively short stroke lengths at 60mm to 125mm.

Most saddles have round rails, whereas some have oval rails. You may need a seatpost with a clamp design that’s deeper to accommodate oval rails. Longer-travel posts do exist, from 170mm up to 210mm, but they can be difficult to use for shorter riders or on certain bike frames. That said, longer-travel posts are becoming more and more common as technology improves and bike manufacturers design frames with shorter seat tubes. The ‘DropLoc’ cable shuttle needs to be set up exactly right, but having the cable anchored at the lever end makes it easier, and once you’ve got it sorted the whole mechanism can be unscrewed for easy removal/refitting. Every brand seems to have its own take on the saddle clamp design, which usually includes a bolt at the front of the head and another at the rear, although some have just one bolt. Our main criticism of the LEV is how the cable is mounted – it’s clamped at the post end instead of the lever. This means accurate cable tension and length is needed to get it working well and it takes longer to set up than posts where the cable is clamped at the remote end.

Seal BMX Switch Pivotal Seatpost

ideal for longer days in the saddle – the Specialized S-Works SL Pave is a prime example. What is the most cost-efficient type of seatpost?

bikes use a diameter of 30.9mm or 31.6mm and there's a great choice of posts to fit these frames. How are bike dropper posts operated?

PNW offers good value for money across its range of products and its Loam dropper post is no exception. A shim should work fine with a standard seatpost clamp that attaches around the outside of the bike’s seat tube, but it might not work properly to hold your seatpost in place without it slipping if you’ve got a more complex clamp design. It’s great to see the 27.2 option if you are running a skinnier posted bike. Andy McCandlish / Immediate Media If you can afford it, Fox’s Transfer is a robust, sweet-performing post that can be switched between internal and external routing. Dropper post internals vary from very complex to relatively simple. The XC-focused DT-Swiss D-232 is one of the less complex options on the market. DT Swiss