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.

Skinnier seatposts are in vogue at the moment for the same reason skinny seatstays are popular: the theory is that they offer greater flex and therefore comfort. Does the frame have some shims that reduce the seat-tube’s inner diameter, allowing such a narrow seatpost to be held in place?SRAM’s Matchmaker and Shimano’s I-Spec standards allow you to combine a dropper and brake lever on one mount to keep the handlebar tidy. Seatpost length ranges anywhere from around 75mm to more than 400mm, though most posts come in lengths between 300mm and 400mm. The BikeYoke Revive 2.0 has always been praised for its smooth action, and our testing led us to think that this could well be the best feeling cable-operated dropper around, with a precise and light lever feel. The Bontrager Line Elite is the higher-specced of two dropper seat posts from the brand, with the lower being the Bontrager Drop Line. Best Lightweight Gravel/Road Dropper: FOX Racing Shox Transfer SL 27.2 Performance Elite Dropper Seatpost

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. The low weight will appeal to XC/trail riders, and there’s even a 27.2mm version (100mm stroke) for hardtails and older frames. It’s got a smooth and easily controlled stroke with a solid top-out thunk that leaves no doubt that it has re-extended. If you don’t have calipers, you’re hard-pressed to get the diameter. An adjustable wrench can be used as calipers, then measure the gap on the wrench. However, it’s almost impossible to distinguish 0.2 mm increments with a tape measure. One (precise) measurement is often better than a thousand expert opinions”– author’s expert opinion. 🙂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. seatposts, like the FSA SLK 20mm Di2 compatible carbon post, which are ready to accept a seatpost-style But measuring the circumference means you only have to distinguish a 0.6 mm difference (because everything is multiplied by 3.14…), which is doable. 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. The introduction of carbon to bike manufacturing was a game changer for seatposts. Not only can it help to reduce the overall weight of the bike, but the way in which carbon components are manufactured – by building up layers of fibres –can be adjusted to give it the perfect blend of compliance and stiffness. From damping to deflection, the best carbon seatposts can help soften vibrations and take the edge off impacts.