It may not seem like the most important component on your bike, but getting the right seatpost plays a key role in putting you in the correct pedalling position.
They can also help make your bike a lot comfier too. Imagine the difference in ride-quality between a basic aluminium and a good carbon frame. It's no surprise that swapping an alloy seatpost for a more flexible carbon one will both save weight and also add comfort where it's often badly needed.
Seatposts come in different diameters – the three most widely used sizes for road bikes are 27.2mm, 31.6mm and the less common 30.9mm.
If you have an aero bike with a non-round seatpost, you’re stuck with what the manufacturer offers.
It’s also worth checking the layback (or offset) of a new seatpost against your current one – the amount the clamp is set back behind the line of the post.
If you’ve had a bike fitting, you’ll need to ensure your new post can recreate the same saddle position (height and distance from pedals) which can be adjusted by sliding your rails through the clamp.
And while we’re talking saddle rails, consider what they’re made of. If they’re carbon you’ll need a compatible clamp as metal rails tend to be a different shape.
Here then, is a selection the best carbon seatpost upgrades to consider...
The best carbon seatposts
Hope Carbon Seatpost
Now producing British Cycling’s latest track bikes, it’s no surprise that Hope’s seatpost is not only designed and tested in the UK - it’s made here too. One seamless piece, incorporated in its carbon shaft are 24 separate carbon fibre plies, allowing the wall thicknesses to vary along its length.
Balancing weight and strength, above this, the head uses almost equally clever aerospace-grade alloy clamps to hold the saddle. Extremely well finished and also quite beautiful looking, it’s strong enough for the biggest riders but still incredibly light.
Coming in three diameters, the 27.2mm version is 350mm long and weighs 185g. The 30.9 and 31.6mm are both longer at 400mm and weigh 220g. All have a 15mm offset. With an RRP of £140, it’s good value too.
Buy the Hope Carbon Seatpost from Tweeks for £126
Pro Vibe Ltd SC Carbon Seatpost
A tough, quality post, with useful Di2 battery integration. Produced by Shimano’s components department, it’s no surprise the Pro Vibe Ltd SC seatpost is both well-made and matches the latest compatibility standards.
The most expensive seatholder in the brand’s range, it’s made entirely of carbon, and at 400mm long weighs 220 grams. Coming in the most common 27.2 and 31.6mm diameters, what really sets it apart is its ability to hold a standard Di2 battery in the base - meaning you don’t have to faff about with bungs and the like.
Available either straight or with a 20mm layback, the clamp comes with plates for both alloy and carbon rails.
With a single titanium bolt taking care of installation and adjustment, you’ll often see this post supporting riders in the pro peloton. For amateur racers, it’s also an excellent choice - regardless of whether you’re running Di2 or mechanical gearing.
Buy Pro Vibe Ltd SC Carbon Seatpost from Tweeks for £159
Specialized CG-R Carbon Seatpost
It took a few back-to-back tests with a more rigid post for us to appreciate the CG-R. It doesn’t entirely insulate you from what’s going on below the bike - you still get plenty of feedback from the road. Instead, it softens the worst of the road buzz, taking the edge off bigger impacts and leaving you happier and less fatigued after several hours in the saddle.
Visually, the kinked profile with its rubberised Zertz damper took some getting used to. Still, it’s worth learning to love, as it’s this design feature that gives the saddle its exceptional vertical compliance. While many posts require a lot of length exposed, the CG-R’s bump-busting magic happens right at the top, making it an excellent option for people on smaller or non-compact frames.
An extremely easy-to-use clamp design is the icing on the cake. Coming only in a single offset 27.2mm version, our test model tipped the scales at 275g. A slight weight penalty, but a massive comfort boost.
Buy the Specialized CG-R seatpost from Tredz for £185
Syntace P6 Carbon HiFlex Carbon Seatpost
Conventional in apperance, this post offers almost the same flexibility as more funky-looking designs. Exceedingly comfortable, this translates to a solid inch of back and forth movement at the saddle should you hit something large enough. Of course, the more post you leave poking out of the frame, the greater the flex effect will be.
One key feature allowing this is the Syntace’s elliptical bore, designed to place more material where it’s needed while removing it from areas subject to less stress. Syntace calls this ‘load-orientated material distribution’ and it seems to work very well. The P6 HiFlex also has a few other tricks to justify its high price, including an excellent saddle clamp, with an extra-wide lower section to support the rails.
Titanium hardware and a 10-year warranty suggest this seatpost is built to last. Available in a full range of diameters, our 27.2 test model weighed in at 235g - respectable for any carbon post.
Buy the Syntace P6 Carbon HiFlex seatpost from Syntace for €250
Canyon VCLS 2.0 Carbon Seatpost
Made of two separate half-round carbon leaf springs, Canyon’s VCLS post allows your saddle to flex backwards by up to 25mm. And unlike some options, it doesn’t need lots of length exposed to accomplish this.
The flex is enough to be visible if you yank the post backwards when off the bike, but while riding, the effect is more subtle. With no irritating superfluous movement, you instead get the feeling that most of the bumps coming up are magically dissipating before they reach the saddle. Hit a pothole and the flexibility becomes more obvious as the post protects your backside from serious trauma.
Although the split design makes set-up more time consuming than a traditional post, it’s a one-off job. Available in 27.2mm only our test model weighed in at a respectable 232g. Still representing a minimal weight penalty, given that there are few situations not made comfier by being perched above this post, it’s worth paying.
Buy the Canyon S14 VCLS 2.0 Carbon Seatpost from Canyon for £233
USE EVO 3K Carbon Seatpost
Weighing as little as 121 grams, this is a seriously light post. An innovative British design, it uses USE’s longstanding clamp design. Keeping it ever so simple, this skeletal assemblage does away with any excess bulk, while remaining easy to adjust. Also using an incredibly light custom lay-up carbon shaft, this allows a little flex for comfort, yet is durable enough for off-road use if you so choose.
Offering a nominal 10mm layback, the adjustment of the seat angle comes via two opposing bolts. Making it easy to strike the perfect balance when setting your saddle, it’s both secure and micro-adjustable. Coming in 300mm or 400mm lengths, the USE EVO 3K Carbon Seatpost is available in 27.2, 30.9 and 31.6mm diameters.
A minimal design approach makes for a sleek, highly-functional seatpost with an incredibly low weight.
Buy the USE EVO 3K carbon Seatpost from Tweeks for £100
Ritchey 1-Bolt WCS Carbon Seatpost
You can’t go far wrong with kit from Ritchey. This simple single-bolt seatpost is great-looking, while its adjustment mechanism is simple and extremely robust. A single side load bolt keeps the clamp together while reducing stress on the saddle rails and keeping the post secure.
Crafted from monocoque carbon, the shaft is very light, while providing a modicum of extra comfort versus an aluminium alternative. Ritchey produces the post in 27.2, 30.9 and 31.6mm diameters, with either a zero or 25mm offset.
You can expect a weight of around 185 grams for the most diminutive 27.2mm diameter model. Ideally suited to a classically styled frame, this Ritchey carbon seatpost promises to be durable and offers top performance with zero additional fuss.
Buy now the Ritchey 1-bolt WCS Carbon Seatpost from Tweeks for £159
How to set-up your saddle position
If you’re swapping your seatpost, now is probably as good a time as any to ensure your saddle is in the right position.
The ‘knee over pedal spindle’ or KOPS method of saddle positioning has long been a bike-fitting staple. Although it’s not a hard and fast rule, it’s a useful starting point to give you a rough idea of where your saddle should be in order to centre your weight on the bike. To start, you’ll need a plumb line and a way of supporting the bike while you sit on it – a turbo trainer is ideal.
A quick spin before making any adjustments will also help you warm up and ensure you’re in a natural position. Once you’re happy that you’ve found the sweet spot where you feel most comfortable on the saddle, stop pedalling. Turn your cranks parallel to the ground, with the leading crank in the 3 o’clock position. Hang the plumb line from the bony protrusion just below your kneecap (you may need to ask a friend to help).
It should bisect the axle of the pedal. If it’s in front or behind, you’ll need to shunt the saddle backwards or forwards accordingly. Loosen the bolts on the saddle clamp to do this – but make sure the saddle is kept level. Repeat the procedure until you’re happy with the position.